Starter/generator for an internal combustion engine, in particular a vehicle engine

The invention relates to a starter / generator for a Internal combustion engine, in particular a combustion engine Of a motor vehicle.

Motor vehicles and other engines equipped with an internal combustion engine Vehicles usually require an electric starter Starting the internal combustion engine and a generator to the Supply of electrical loads as well as charging of a Battery, which, among other things, contains the electrical power required for starting Energy supplies. Since the early days of automobile construction Starter and generator usually two separate electrical Machines that are specific to their particular function Are adapted. A starter must have relatively high torques Relatively low internal combustion engine speed and Is therefore conventionally high against the internal combustion engine translated. It does not run continuously, but Is used only for the starting process with the internal combustion engine . A generator runs continuously with the Combustion engine and reaches at a relatively high ratio High speeds.

The union of these two functions in one and the same Electrical machine is an aspired target, Since one of the two conventionally required Machines can be saved.

One way, despite the different requirements To connect both starters and generator both machines From G. Henneberger: "Electric Motor Equipment", Vieweg, Braunschweig 1990, pp. 98-103. According to this proposal Starts the electric machine - at which it is Is an inverter-controlled rotary field machine - Does not accelerate the internal combustion engine itself (Flywheel decoupled from the internal combustion engine). When a sufficiently high rotational speed is reached, The flywheel with the aid of a friction clutch with the crankshaft Of the internal combustion engine. The in the flywheel Stored rotational energy then throws the internal combustion engine at. The electric machine is in the generator mode Permanently through the friction clutch with the internal combustion engine . This solution has the advantage that the performances And torques of the electric machine at starting and In generator operation. However, the Large mechanical load on the friction clutch during coupling Of the fast-running flywheel, which inter alia leads to clutch wear , And a dead time before each start-up process, Each for accelerating the flywheel Is required.

From PCT / SE91 / 00272 is an electrical asynchronous machine Known alternatively as a generator or as a starter able to work. It is equipped with a control unit with one Battery. Another starter / generator is For example, from EP-A-0 569 347.

The invention provides a starter / generator for a Internal combustion engine, in particular a combustion engine Of a motor vehicle, with an electric rotary field machine, The starter and generator function exerts; And at least one inverter, which is provided for the The magnetic fields of the electric machine Voltages and / or currents of variable frequency, amplitude And / or phase by sinusoidal pulse modulation A clock frequency greater than 10 kHz; Wherein the inverter An intermediate circuit with an opposite circuit Electrical system; And wherein the Inverters in the intermediate circuit with an energy store For storing energy for starter operation is; Wherein both the energy extraction from the intermediate circuit In the starter mode of the electric machine as Also the energy feed into the intermediate circuit in the generator mode On the elevated voltage level (claim 1).

An "electric machine" is any kind of machine for Rotational motions, both as an electric motor, such as Can also be operated as an electrical generator. Under "rotary field machine" - as opposed to a Electricity machine - a commutatorless one Machine in which a magnetic rotating field occurs, Preferably 360 °.

The inverter can be used for the magnetic fields Required voltages and / or currents with (within certain Limits) freely selectable frequency, amplitude and / or Phase.

Preferably, the electric machine starts the internal combustion engine In a state of convergence from the state (claim 2). At the A "cohesion" remains the ratio of the current Rotations of the electric motor and the drive unit - in contrast to the above - mentioned flywheel starter Is essentially constant (and, in particular, it has the Value one). Conflict "from the state" means that the Electric machine and the drive unit - other than In the above-mentioned flywheel starter - together from the state Up

Because of the confluence from the state<ul><li>Starting is fast and without dead time,</li><li>The starter / generator is practically wear-free,</li><li>The starter / generator reaches a relatively high level Efficiency (since no energy for clutch heating And wear is consumed),</li><li>Can be the clutch between internal combustion engine and electrical Machine.</li></ul>

The electric machine runs - unlike a conventional one Starter - advantageously permanently with the internal combustion engine. A one-way and free-wheeling device required there Can therefore be dispensed with here.

Preferably, the relative rotational speeds of the internal combustion engine And electrical machine in starter and generator operation (Claim 3). That is, the translation of the Electrical machine is the same in both operating modes, And does not become the transition from starter to generator operation Reduced.

In principle, the coupling of the electrical machine With a drive shaft of the internal combustion engine, Eg via a transmission. The electrical machine is preferred But directly to the drive shaft of the internal combustion engine (Eg the crankshaft) or a drive train (eg Of the drive shaft of a clutch or a gear- Or automatic transmission) 4). A "direct" coupling "means, in particular, a Gearless coupling of the rotor of the electric machine With the drive shaft. This is not the case About an indirect coupling via pinion or traction means (Eg V-belts). The rotational speed of the rotor is preferably the same Of the speed of the internal combustion engine.

Particularly preferred is an embodiment in which the Electric machine on the drive shaft Couplable extension and is non-rotatably connected to it (Claim 5). Benefits are a relatively minor Effort due to the small number of moving and force transmitting Parts, wear-free as well as complete Noise at startup.

The electric rotary field machine is preferably one Asynchronous machine, a synchronous machine or a reluctance machine, In particular for three-phase current, for example three-phase current (Claim 6). An asynchronous machine generally has one Relatively simple rotor (usually a rotor with Short circuits or windings, the ends of which are connected Abrasive rings are guided), in which by the magnetic Rotating fields of the stator, which precede the movement of the rotor Lag, currents are induced. It therefore shows With regard to the cost of production and mechanical costs Load-bearing advantages, however, is control technology More expensive, since the magnitude and phase angle of the rotor current Load-dependent, but not directly measurable via stator sizes, But can only be calculated. On the other hand, synchronous machines Runners with predetermined pronounced poles, the By permanent or electromagnets. The Electromagnets can, for example, be supplied with current via slip rings Are fed. Synchronous machines have in general Higher production costs, but are control engineering Easier to handle, because the torque in the Is essentially dependent on the rotor angle which is determined by means of a Rotor position encoder is directly measurable. They also require it A lower effort in the field of power electronics More compact, have a lower cooling requirement And achieve a better efficiency. Reluctance machines Belong in the wider sense to the synchronous machines.

Asynchronous machine, in particular, is controlled Of the electrical machine, preferably on the basis A field-oriented regulation (so-called vector regulation). In this case, starting from directly measurable instantaneous Sizes, such as applied voltage, stator current and speed, if applicable, Based on a computational dynamic machine model The stator current into a torque-forming component, Which generates the torque with the rotor flux, and a Perpendicular thereto and generating the machine flow Component is computationally decomposed and thus the torque is determined. This control technology allows - although the Current ratios in the rotor are not directly measurable To set the desired torque with high accuracy.

The starter / generator according to the invention is the following Around an auxiliary system associated with the internal combustion engine. Because of its auxiliary character, it should be relative to the internal combustion engine Little space, so as possible To be compact. The starter / generator must start Relatively high torques can be applied and is intended for the Generator function have the highest possible efficiency. The advantageous measures mentioned below Serve a compact design with a high torque output And high efficiency.

A measure for achieving high compactness is that, That the rotating field generating unit of the electrical (Ie, the stator) at least 8 magnetic Poles (relative to 360 °) (claim 7). Especially Advantageous are finer pole divisions, corresponding to eg 10, 12, 14, 16 or more poles (for circularly closed Machine). To the way in which three-phase windings With a certain number of poles, For example, reference is made to G. and H. Häberle, "Electrical Machines in Power Engineering Systems ", Verlag Europa-Lehrmittel, Haan-Gruiten, 3rd edition, 1994, pages 169 - 172.

A high number of poles allows, among other things, the winding heads Of the stator is small in both axial and axial directions Also in the circumferential direction of the machine, so that the machine In the axial direction as a whole Can Preferably, the axial projection of the winding heads is On each side of the stand only 5 - 25 mm, in particular 10-20 mm. The axial width of the stator back is Preferably 25-100 mm. For a supernatant of 2 Times 15 mm and a back width of 40 mm For example, an overall axial width of the stator of FIG Mm, the ratio of back width to total width 0.57. This ratio is preferably between 0.4 and 0.8, particularly preferably between 0.55 and 0.8. Besides the advantage of a more compact design of the machine Are smaller wobble heads because of the smaller winding wire length Require less non-active winding wire - The ohmic losses are reduced. Furthermore, the stray field (Which substantially determines the reactive power ratio) is smaller, Since it depends on the winding head surface.

A fine pole pitch allows, among other things, the stand back For the magnetic reflux thinner (and thus also Lighter), with the result that, with the same outer diameter The machine of the runners a larger Diameter. Greater rotor diameter Because of the longer air gap and the Larger effective lever arm to a greater torque. The thickness of the back in the radial direction that is composed From the height of teeth and the thickness of the continuous Preferably 10 to 50 mm, preferably 15 - 30 mm and is particularly preferably smaller Or equal to 25 mm. The outer diameter of the back is Preferably 230-450 mm and particularly preferably 250 mm - 350 mm. The ratio of double back thickness to Back outer diameter is preferably 0.05-0.25 and Particularly preferably 0.1-0.2. For example, a Machine with a back outer diameter of 300 mm Tooth height of 15 mm and a thickness of the continuous back part Of 10 mm, in total a return thickness of 25 mm Mm. The above ratio is then 50 mm to 300 mm, that is 0.167.

Overall, this results in a fine pole pitch, small winding heads And a thin stand back to a more compact And lighter machine.

In high-speed rotating field machines, high pole numbers are required Unusual since they have a relatively high pole frequency Conditions. A common value for the pole change frequency is For example, 120 Hz Is advantageous A high maximum polarity frequency, preferably between 300 and 1600 Hz and more, particularly preferably Between 400 Hz and 1500 Hz (claim 8).

In order to determine the influence of eddy currents in the stator, Frequency change frequency The stator advantageously has thin stator plates, preferably Having a thickness of 0.35 mm or less, particularly preferably 0.25 mm or less. As a further measure In order to reduce the losses, the stator plates are preferred From a material with low losses of magnetization, In particular less than 1 Watt / kg at 50 Hz and 1 Tesla (claim 9).

As a further measure, resulting in a compact training The electric machine advantageously has one Internal fluid cooling (claim 13). In the fluid, It is basically gas (eg air) and advantageously Liquid (eg oil). A cooling system exists In that the machine inside (ie in the rotor Absorbing space) completely under cooling liquid. A disadvantage, however, is that above about 500 min^-1Turbulence losses occurring above about 2000 min^-1Can have considerable proportions. To counter this, The supply of the cooling liquid is advantageously carried out with loss- And / or speed-dependent, preferably With a spray liquid cooling. In the machine There is always only essentially enough cooling liquid, Such as momentarily to dissipate the power loss Is required. At very high power losses and / or Low speeds can make the whole machine under Cooling liquid. Spraying liquid cooling Provides a highly effective heat transfer as well as a Particularly good distribution of the liquid.

The electrical machine preferably has its own Closed coolant circuit. For the removal of the Heat to the outside (eg into the atmosphere) this one Autarkic recoolers (eg an air cooler). However, it is also possible to have a parasitic recooler, which Which introduces waste heat into another cooling system, in which Eg around the combustion engine or transmission oil cooling circuit Of a motor vehicle. The waste heat is then Through the recooler of the other cooling system to the outside The The parasitic back cooler can be very simple and Compact, for example in the form of a cooler, The cooling liquid of the other cooling system is immersed And due to the good heat transfer only one relative Low surface area. Alternatively, the electrical Machine but also no own closed Cooling circuit, but can be in another cooling circuit For example, into a transmission oil cooling circuit.

In order to achieve particularly high torques, the Electrical machine preferably strongly in the range of magnetic Saturation. A measure of magnetic saturation Is the current (at maximum torque) in the stator Per cm Air gap length in the circumferential direction. Preferably This dimension is at least 400-1000 A / cm, particularly Preferably at least 500 A / cm (claim 14). Another The measure for magnetic saturation is the so-called flattening factor: It indicates how strong in sinusoidal excitation current The ratio of peak to arithmetic Is the mean value of the magnitude of the magnetic field. It is included Pure sinusoidal course 1.57, with usual electrical Machines about 1.35, and in this preferred embodiment 1.05 - 1.15. Working strong in the saturation range Has the further advantage that the machine has a relative Wide air gap between the operating units (generally runners And stands). The width of the air gap is Preferably 0.25-2.5 mm, preferably 0.5-1.5 Mm, and particularly preferably 0.75-1.5 mm. changes Of the air gap - as is the case with radial vibrations of the Rotor-bearing shaft - have an effect on the Operation in the saturation range. In addition to robustness Against radial vibrations allows this measure Also a reduction of the accuracy requirements and So as to make a considerable simplification of the production of the Electrical machine.

Quantitatively, the compactness can be determined by its size "Torque Density". Preferably, the electrical Machine has a high torque density The maximum torque, which is particularly preferred Greater than 0.01 Nm / cm³ (Claim 15).

A compact electric machine has been developed in the Generally a relatively low inductance. Around Here Nevertheless, for example with the aid of a clocked voltage A smoothest sinusoidal current for generating Of the electric rotating fields, the inverter operates With a clock frequency greater than 10 kHz, in particular 20 kHz to 100 kHz and higher. A high clock frequency Also has the advantage of a compact design of the inverter Even for example: Voltage intermediate circuit inverter is the capacity in the DC circuit, which corresponds to the electronic switches of the Inverter provides the intermediate circuit voltage, Inversely proportional to the frequency, so that at higher A smaller capacity is sufficient for this purpose. The Smaller intermediate circuit capacitors can be equipped with short Line circuits directly next to the electronic switches to be ordered. Further, a necessary EMC filtering (EMC: Electromagnetic Compatibility) of the inverter To be more compact, since the size The filter is inversely proportional to the clock frequency.

An "intermediate circuit" is understood to mean a circuit which Substantially DC voltage From which a downstream inverter part (the So-called machine inverters) by pulsing or clocking Variable alternating voltages or currents. These DC voltage or this direct current must therefore be supplied with a large current Flank slope. A vehicle battery Is usually too slow for this, so you use eg A capacity as energy storage in the intermediate circuit. in the Generally, an intermediate circuit inverter comprises three Modules, namely an input module for supply With or removal of electrical energy, an output module In the form of the machine inverter and the Intermediate intermediate circuit.

As a further advantageous measure for achieving a compact Construction of the inverter are electronic Switch of the inverter is fluid cooled, preferably Boiling-bath cooled (claim 16). As a boiling bath coolant can For example a fluorocarbon. The liquid coolant evaporates during the boiling bath cooling To heat sources and thereby deprives them of their relative High evaporation heat. The steam rises and can, for example, be In an external condenser and thereby heat its evaporation submit. This cooling technology allows for the most compact Arrangement of the electronic switches of the inverter Without any heat sinks. In addition, In order to achieve high cooling performance, it is also relatively small Temperature differences are sufficient: during air cooling Usually a temperature difference of 40 ° C Between the cooling surface and the housing of a cooling element to be cooled Chips is necessary, a difference of 2-10 ° is sufficient C, in particular about 5 ° C. As a result are high Ambient temperatures tolerable, for example in a Chip temperature of 65 ° C an ambient temperature up to 60 ° C. The absence of heat sinks and the high achievable Compactness also allows high vibration resistance; The boiling water also allows the creation of a Oxygen - free atmosphere in the electronic field Components of the inverter, which is a lifetime extension Effects. The housing forming the cooling chamber When it is made of conductive material, Also serve as shielding. Electrical intermediate circuit storage elements For providing voltage to be clocked Or current to be clocked (eg the above capacity) Can be arranged inside the cooling housing, as a result of which Short lead paths. An optional separate Electric brake energy storage can be within or Outside the cooling housing. Those in the latter There may be relatively high supply inductances Do not interfere, since the brake energy store on a Relatively "slow" time scale.

A further cooling-technically advantageous measure exists In that several electronic switches of the inverter, Especially 2 to 20 and more, in parallel 17). The parallel circuit leads to a distributed one Arrangement of the heat sources and thus a relatively small Power density.

The inverter advantageously comprises a switch semiconductor switch, Preferably fast semiconductor switches, such as Field effect transistors - particularly preferably metal oxide semiconductor (MOS) field effect transistors, bipolar transistors And / or bipolar transistors with insulated Gate connection (IGBTs) (claim 18). Under "fast" semiconductor switches Are understood, in particular, Which allow the above clock frequencies. MOS field effect transistors Have at relatively high clock frequencies the relative Least losses. They have an ohmic characteristic (While other semiconductor devices in general Have a fixed loss characteristic), so that in the partial load operation The losses are relatively low.

The inverter is a pulse inverter, ie Generated for the magnetic fields of electrical Machine and / or currents By pulses, in particular on the basis of pulse- Or pulse amplitude modulation. He can do this with advantage Help electronic switches do the pulses off A predetermined direct current or alternating voltage or a DC or alternating current. For example, in the case of an intermediate circuit inverter with Constant intermediate circuit voltage can be estimated by sinusoidal Pulse width modulation at high clock frequencies Of the machine inductance almost sinusoidal currents Arbitrarily adjustable frequency, amplitude and / or phase Respectively. For pulse amplitude modulation, for example, one proceeds Off from an inverter with variable Voltage and thus generates pulses of different types Amplitudes.

To get the high electrical power required for the start - up process Power without excessive load on the vehicle battery An energy storage device is provided which comprises: Is charged with energy before the start - up and the Then the required energy is withdrawn at short notice. For this purpose, the inverter is an intermediate circuit inverter , Which in the intermediate circuit has at least one Energy storage for the starting energy. In which Memory can be, in particular, an electrical, Magnetic and / or electrochemical storage, such as a An inductor, and / or a (fast) battery act. This can be next to storing the starting energy Also serve other tasks. For example, The energy required for pulse operation of the inverter save. (In the latter case it could be combined with the usual Intermediate circuit memories coincide). In addition, the Design of the converter as intermediate-circuit converter In any case - eg also without memory for the starting energy And possibly the brake energy.

Conventional motor vehicles, other vehicles and vehicles Also stationary power units, there are often auxiliary machines, Since they absorb relatively high power - mechanically from the drive unit (ie from the internal combustion engine) For example via belt drives. Here Can be eg air conditioning machines, servo drives (eg For brake and steering assist), pumps or the like act. Such a mechanical drive coupling is Ia not optimal, since the auxiliary machine belongs to the drive unit Through the speed states specified by it have to be. It does not, on the one hand, remain constant with it Optimal operating parameter (eg the speed at a rotary Auxiliary machine) and on the other hand also If this is not the case, Would not be necessary. These disadvantages can be satisfied with the inventive Starter / generator, as a high-performance machine Can be overcome. The electric Machine provides current at a relatively high voltage level, Preferably in the upper region of the low voltage, Where just not yet provided for special protection against contact (Eg about 60 V DC). One goes Moreover, is preferably a range of 250-450 Volts. The auxiliary machines are advantageously operated Electrically from the intermediate circuit at these high voltage levels (Claim 19). Such a high voltage level Is connected in the intermediate circuit with an intermediate circuit inverter Already before, and so does not need particularly for This additional purpose. An electric Instead of a mechanical auxiliary machine drive is therefore Possible because of the high voltage level relative Small currents (as opposed to the 12 volt voltage level, for example) Of a conventional motor vehicle network). The auxiliary machines can be driven electrically in the Need to run at their optimum speed and Otherwise switch off. This results in a significant increase Of the total efficiency. All are beneficial Devices and auxiliary drives of a motor vehicle Operated. The internal combustion engine then only serves as a main drive motor For the vehicle as well as the driving motor of the Generator. For low-power users, a conventional Low-voltage distribution network (eg 12 V or 24 V) be provided. A battery can be in the area of ​​the low-voltage on-board network Can be arranged.

Another (further) inverter is also advantageous Supply of 220 V alternating current and / or 380 V three-phase current With a typical network frequency (eg 50 Hz). The supply This further inverter can also be made of The (DC) intermediate circuit. A thus designed Vehicle allows the supply of normal electrical And thus provides a mobile mains power generator For example, advantageously in external work Can be used.

The conversion of electrical energy from the intermediate circuit In alternating current can also be advantageous for the supply of a Voltage vehicle electrical system of the vehicle. One such Network has the advantage that from the wiring system By transformers in the individual consumers any, Voltages adapted to the respective loads Can be produced. The alternating voltage is particularly advantageous High frequency (ie the frequency is greater than 1 kHz), since then the transformers are particularly small and Can be easily formed.

The possibility of the starter / generator as a high performance machine To a high voltage level Its use for heating purposes in the vehicle (claim 20). This may be, for example, electric heating Of the internal combustion engine, for example by heating the cooling circuit (Especially for winter operation of direct Injecting turbo diesel engines), a passenger compartment, An exhaust gas catalytic converter of the internal combustion engine, Fuel filter, a windshield washer system, exterior mirrors And / or window windows of the vehicle. Such heating systems are used in conventional motor vehicles Either not, only inadequately or only by waste heat Of the internal combustion engine. Electric heating Has - with the exception of the increase in the number of civil servants, for example, with support A passenger compartment heater - beneficial Impacts on the environmental friendliness of motor vehicles: Electric motor and catalytic converter heaters The internal combustion engine or the catalytic converter rapidly Operating temperature, and also allow accurate and Fast control of operating temperatures. These are important Measures to meet strict emission regulations. The control and regulation of the various heaters, In particular of the engine and catalytic converter heating, of The control of the starter / generator for the control of the Inverter.

Due to its low noise and wear, as well as the Missing dead time, the starter / generator is very common Starting. It is therefore advantageously provided with a Start-stop control of the internal combustion engine Which the internal combustion engine only runs when necessary and Is otherwise switched off (claim 21). Because in city traffic Combustion engines of motor vehicles More frequent holding at traffic lights and crossroads a considerable Part of their operating time at idle. This Represents a considerable waste of resources and environmental pollution Because it is a useless additional consumption Of fuel with consequent emission of toxic, climate-active Or otherwise harmful exhaust fumes.

The automatic start-stop control is preferred An automatic stop of the internal combustion engine, When a stop condition (or one of several) is met Is. To define a stop condition, you can use different Conditions alone or in (sub) combination, Eg: zero load, shift operation, idle, standstill of the (Ie driving speed below one Specific small value, eg 4 km / h), internal combustion engine Is disengaged, no gear is engaged, the service or Parking brake is actuated, actuation of a stop switch.

Accordingly, the start-stop control preferably causes When a starting condition (or one of Several) an automatic start of the internal combustion engine With the help of the electric machine. Also to the definition The start condition can be different conditions alone Or in (sub) combination, eg: actuation of the Accelerator pedal, release of the operating brake or parking brake, actuation Clutch, touching or moving a gear shift lever, Engaging a gear, pressing a start switch.

Conventional starters bring because of their high ratio The internal combustion engine only to a relatively low starting speed (Typically 80-250 rpm), which is far below Whose idle speed (typically 600-800 rpm) lies. The speed difference between the start speed and Of the idle speed, the internal combustion engine then has to stop Own power. However, he needs to do so It is at these speeds far below its idling speed In a very unfavorable operating area - a relatively large quantum of fuel, which Also burns incompletely. Every engine start is Therefore with additional fuel consumption and particularly Emissions. Preferably Therefore the drive system is designed in such a way that the electrical Machine at least substantially until reaching Of the idle speed of the internal combustion engine (which occurs at Operating temperature usually between 600 and 800 rpm ) Is driving. This measure leaves the internal combustion engine Practically only when the idling speed is reached And thus leaves the operationally unfavorable Acceleration can be avoided on your own. It diminishes Fuel consumption and the most harmful Emissions during start-up and also makes the start-up process more quickly. The measure is therefore for vehicles with and Without start-stop automation is ecologically particularly advantageous.

Advantageously, the electrical machine can be used in addition to its functions As a starter and as a generator other functions run:

A first advantageous additional function is that The electric machine can accelerate and / or decelerate Of the shaft, for example To accelerate or decelerate the motor vehicle (Claim 22). The electric machine can be used for deceleration As wear-free, for the purpose of energy recovery Generator (retarder) brake. In connection With an anti-skid (ASR) control, the Electric machine by braking quickly the total drive moment And thus the slip of one or more Reduce driving wheels. With a driving additional torque For the purpose of acceleration support, the Combustion engine with unaltered achievable vehicle acceleration values To be weaker That it operates on average at a higher medium pressure and therefore Less fuel consumption. Thus this measure also contributes To reduce harmful emissions. The Acceleration support can advantageously be so controlled Be the torque characteristic of the internal combustion engine For example, by operating in a rotational speed range With relatively low torque (eg in the so-called "turbocharger" In a turbocharged engine) Greater additional torque than in others Speed ​​ranges.

The second advantageous additional function is the electrical one Machine as an electromagnetic clutch in the drive And / or as an active transmission synchronizer (Claim 23). It can be used instead or in addition to a Conventional friction clutch or a conventional hydrodynamic clutch Converter. In an advantageous embodiment The electrical machine is designed as a whole Rotatably mounted, thus also has, in addition to the rotatable rotor A rotatable stand. One of these elements (runners Or stator) is connected to the combustion engine, eg from the internal combustion engine Drive shaft, the other with the eg to the Transmission output shaft. By setting a (Ie, a decreasing relative rotational speed) Slip) between the rotor and the stator is the transient Operation as for coupling a friction clutch Is achieved. Disappointing clutch slip is at the end Of the engagement process. To avoid electrical losses Can then advantageously be a mechanical bridging clutch . For generating the generator function One is set - without bridging clutch Slightly decelerating clutch slip. To start The output shaft is placed, for example by means of a braking device , Against which the torque support during starting Of the electrical machine. As part of a ASR control can be the traction slip instead of by braking Also by increasing the coupling slip (after loosening A lock-up clutch). As active Synchronization of the gear mechanism works the electrical Machine braking in the direction of the drive shaft or Acceleratingly to the output shaft leading to the transmission, Depending on how this occurs during the course of a gear shifting operation to the Achieving synchronism of gear wheels becomes.

A third additional function is that the electrical Machine actively reduces rotational irregularities, By providing a fast alternating torque antiphase To the rotational nonuniformities (claim 24). This alternating torque can be the constant or Slowly varying torque of the generator function or Possibly superimposed on the braking or booster function be.

In the case of the rotational nonuniformities, it is possible in particular Are those which occur in the internal combustion engine (in particular Is a reciprocating internal combustion engine) By the gas and / or mass forces acting on the crankshaft Of the individual reciprocating pistons. For example A four-cylinder four-stroke engine shows relatively large rotational irregularities In the second order (ie the double The rotational frequency of the motor). In addition, there are rotational irregularities At higher orders as well as stochastic Occurring non-uniformities.

In embodiments in which the electrical machine Also acts as an electromagnetic clutch, can be connected to the Spot of fast alternating braking and driving Torque a rapidly varying larger and smaller Coupling slip.

"Fast" is a variation in the frequency range Of the rotational non-uniformities to be reduced, For example in the rotational nonuniformity of the second order and At a speed of 3000 min^-1 A variation with a Frequency of 100 Hz. On the other hand, the generator function varies Or other of the above functions Torques are generally slow or they are constant.

They are therefore also referred to as "equal torques" called.

If the amplitude of the alternating current is greater than that Constant or slowly varying torque The total torque of the electric machine - though Opposite the zero line - alternately positive And negative values. Otherwise, the total torque Only positive or negative, whose amount is a fast Varying portion.

The energy obtained in these additional functions (ie Eg during vehicle braking, starting with "grinding" Clutch, deceleration of gear wheels, braking at positive Rotational uniformity) is advantageously used in the process described above (Or another) energy storage device And for generating driving torques (Eg to the vehicle acceleration, acceleration of gear wheels, Driving at a negative rotational nonuniformity) Reused and / or placed in a vehicle vehicle network And / or a battery. At very large (As described, for example, during start-up With "grinding" electromagnetic clutch ), The energy storage can advantageously be used as Flywheel store, its flywheel Powered by an electric machine Is braked. Alternatively, these large amounts of energy For example by an electric heating coil, Which are arranged parasitically in the cooling circuit of the internal combustion engine Is (similar to a diving dip).

In order to prevent vehicle braking with the help of the electrical Engine to achieve the highest possible efficiency of braking energy recovery It is advantageous to decouple During braking the electric machine of the internal combustion engine, Eg with an intermediate clutch, for example A friction clutch or a claw clutch.

For optimum utilization of, for example, in a motor vehicle Available space, it is advantageous that Into the electric machine, in particular in its electric motor Rotor, a clutch, preferably one as a driving clutch Friction clutch is integrated. For example, An asynchronous and synchronous machine with internal Runners can run the runner in his inner area And thus hollow to receive the coupling be. By this measure it is possible that the Electric machine integrated inside the rotor Clutch in the axial direction only as much as or hardly More space than in a conventional one The clutch alone. Because of the reduced Available diameter and minimizing the inertia moment Is also an execution as Multiple disc and / or lamella coupling possible. Is the Integrated clutch is designed as a wet clutch, Clutch fluid also for cooling the electrical machine to care. The actuation of the clutch can be effected mechanically, Electric, magnetic, electromagnetic, hydraulic, Pneumatically or with mixing molds thereof.

Incidentally, throughout the present description Numbers "x" in the sense of "at least x", and only preferably In the sense of "exactly x".

The invention will now be described with reference to embodiments and Of the attached schematic drawing. In Of the drawing,<dl tsize="6"><dt>FIG</dt><dd>An inordinate-schematic representation of a Drive system with an embodiment of the Starter / generators;</dd><dt>FIG</dt><dd>A schematic exemplary representation of the Function of the starter / generator with additional function "Active vibration damping";</dd><dt>FIG</dt><dd>A schematic sectional representation of an electrical system Machine with cutting plane perpendicular to the axial direction;</dd><dt>FIG</dt><dd>A schematic sectional representation of an electrical system Machine with integrated friction clutch With cutting plane in the axial direction;</dd><dt>FIG</dt><dd>FIG. 6 is a schematic circuit diagram of a device Starter / generator used;</dd><dt>FIG</dt><dd>A schematic representation of an electrical Machine with rotating electromagnetic action units.</dd></dl>

In the figures, essentially functionally equivalent Parts have the same reference symbols.

The drive system of a motor vehicle illustrated in FIG. 1, Eg a passenger car, has a drive unit A combustion engine 1, For example, a four-cylinder four-stroke Otto or Diesel engine. The fuel generated by the internal combustion engine 1 Torque can be transmitted via a drive train 2 to drive wheels 3. In the output direction is in the drive train 2 after the internal combustion engine 1 first As a starter / generator. These are followed by a driving clutch 5, a transmission 6 and an axle drive 7, which transmits the torque to the Drive wheels 3. For clutch 5 and gearbox 6 can be a friction clutch and a manual transmission act; Alternatively, for example, an automatic Clutch or converter clutch, each with, for example, manual actuated clutch Manual gearbox or automatic transmission. In other embodiments (not shown), Drive train 2 between the internal combustion engine 1 and the electric motor Engine 4 has a further (controlled-actuated) clutch Arranged to brake with the electric machine 4 to avoid a running of the internal combustion engine 1.

The electric machine 4 - here a three-phase traveling-wave machine In asynchronous or synchronous design A stand 8 and a rotor 9. The former is supported Non-rotatably against the internal combustion engine 1, a (not shown) Vehicle chassis or a clutch housing (not shown) , The latter directly on a propeller shaft (Crankshaft) 10 of the internal combustion engine 1 or one Extending therefrom and coupled to the latter in a rotationally fixed manner Is. The drive shaft 10 and the rotor 9 thus rotate Common, without interposing a transmission.

The electric machine 4 performs several functions: Acts as a generator for charging a vehicle battery 11 and for supplying electrical loads And thus replaces a conventional one in the motor vehicle Existing alternator. On the other hand, it acts as Starter which drives the internal combustion engine 1 in the convergence The booth starts and can thus also a conventionally Separately provided for the motor vehicle replace. The electric machine 4 has further optional Functions: A generator function with much larger Torque is used to decelerate the vehicle or vehicle Internal combustion engine 1. In addition, the electric machine 4 act as an additional drive ( "booster"), for example, the Combustion engine in accelerating the vehicle. Also, it can act as an active rotation uniformity reducer (Figure 2). Finally, she acts Due to the mass moment of inertia of the rotor 9 Flywheel and so can be the case with conventional motor vehicles Ia existing flywheel mounted on the crankshaft replace.

The electric machine 4 is cooled by a spray liquid 12 inside cooled. After passing through a recooler 13 and a pump 14, the cooling liquid- Here a suitable oil - to the rotor 9, specifically in the Near its rotation axis. It migrates due to Of rotor rotation due to centrifugal force Cools the rotor 9 and the stator 8, and then exits Housing 15 of the electric machine 4, To enter the cooler 13 again. The flow of coolant is dependent on the performance and the speed By appropriate control of the pump 14, That in each case essentially only one just needed Minimum amount of cooling fluid inside the housing 15. A compensating vessel (not shown) allows This variation in the amount of cooling fluid in the housing 15. For others (Not shown), the radiator is configured as Parasitic cooler, for example, into the cooling circuit of the internal combustion engine Is used. Further (not shown) The electric machine has the embodiments Does not have its own closed cooling system. they (Or only the rotor) is, for example, inserted into a coupling and / or Gearbox housing and is supported by a housing Lubricating and / or cooling fluid (eg clutch or clutch) Gear oil) with cooled.

In simpler (not shown) embodiments, FIG To which the electrical machine 4 has no additional functions High continuous power, the cooling can be easier : Here, for example, one Internal cooling with gas or only external cooling of the stand With liquid or gas.

The electric machine 4 is also provided with a rotary transformer 16 (so-called resolver), which is preferred More than 8 poles, eg 12 poles. It exists From two adjacent printed circuit boards, from One of which is fixed, and the other is connected to the drive shaft 10 rotates. The printed circuit boards bear on their facing surfaces Surfaces formed by conductor tracks, in such a way That a rotational-angle-dependent transformer-ratio Respectively. The rotary transformer 16 operates According to the transponder principle: the fixed turns (Fixed board) are actively supplied with current / voltage And radiate electromagnetic energy to the Rotatable turns (rotatable plate). Latter Radiate a part of this energy back, whereby This part due to the rotation-angle-dependent transmission ratio From the angle of rotation. The back radiated Part is generated in the fixed turns Angle-dependent signal. An evaluation of this signal Supplies the instantaneous rotational angle of the drive shaft 10 An accuracy of at least 0.5 degrees. For simpler An incremental encoder is used, or Completely dispensed with a corresponding encoder.

An inverter 17 supplies the windings of the stator 8 of the electric machine 4 at a very high clock frequency (Eg 10-100 kHz) pulse-width modulated Voltage impulses, which are under the action of the machine inductance Substantially sinusoidal three-phase currents The amplitude, frequency and phase of which are free Preselectable.

The inverter 17 is a voltage intermediate circuit inverter And comprises three assemblies: a DC voltage converter 18 (input module), which is DC voltage From a low level (here 12 V) to a higher level Intermediate circuit level (here 350 V) and in the opposite direction An electrical intermediate circuit store 19, Here a capacitor or an arrangement is arranged in parallel And a machine inverter 20 (Output module), which is composed of the intermediate circuit-equal The (pulsed) three-phase alternating voltage is more variable Amplitude, frequency and phase, or - at Generator - operated operation of the electric machine Any alternating voltages into the intermediate circuit dc voltage Can be implemented. In other (not shown) The intermediate circuit level is at the upper level Edge of the low-voltage region permissible without special contact protection, Here 60 V.

The three assemblies 18, 19, 20 of the inverter 17 are Is hermetically sealed in a shielding case 21, Which is filled with a suitable boiling coolant Is. This is, for example, a fluorocarbon, Which at a suitable pressure (for example between 50 mbar and 3 bar) have a suitable boiling point, eg 60 ° C. Evaporated boiling coolant may be in a condensation condenser 22 and condensed in liquid form A hermetically closed circuit into the housing 21 to return.

The DC voltage converter 18 is at the low side With the vehicle battery 11 and various low voltage consumers 23, such as lighting and lighting Electronic devices. The inverter 17 can On the other hand current at a low voltage level for charging Of the vehicle battery 11 and supplying the low voltage consumers 23, on the other hand it can be the vehicle battery 11 Current at low voltage level for starting Of the internal combustion engine 1. For others (not Shown), the vehicle battery is located To intermediate circuit level and is directly connected to the Intermediate circuit.

The intermediate circuit store 19 is connected to a External auxiliary memory 24, which is an electrical Memory, here a supplementary capacity 25. The additional accumulator 24 relieves the vehicle battery 11 During the starting process of the internal combustion engine 1 Before starting energy is only taken relatively slowly and In the additional memory 24. Here it is For a quick removal during the start process. In addition, it can also store the energy that is In the case of the electric machine 4 Braking operations. Finally, he has the task, Which in the case of rotational nonuniformity reduction in one Braking phase The subsequent drive phase. For big The supplementary memory 24 can be supplementary Or alternatively a flywheel memory 26.

On the other hand, the (inner) intermediate circuit store 19 has essentially the same The task of the machine-inverter group 20 voltage with the high flank steepness necessary for the clocking So quickly. He needs it No very high capacity (he has eg 2 μF), vorteilhaft For the speed are rather small supply inductances, Resulting from the arrangement inside the inverter 17 is ensured (and preferably On the same PCB, on which the electronic Switches of the machine inverter 20). The additional memory 24, on the other hand, can operate relatively slowly, So that the supply capacitances due to the External arrangement. The additional capacity 25 Can be, in particular, 50 to 10,000 times greater (it is Here, for example, 4.7 mF for the storage of the rotational nonuniformity energy) Than that of the intermediate circuit storage 19.

Even larger storage capacities are with the flywheel memory 26, which has its own inverter-controlled Electrical machine 27 and a drive coupled thereto Swinging mass 28. The latter may be replaced by a separate Flywheel formed or in the rotor of the electric Machine 27. The moment of inertia Of the inertia mass 28 is preferably 0.05 to 2 kgm². It is also possible to operate in the flywheel memory 26 A multiple of which is used to start the internal combustion engine 1 Needed energy to store and give him to start fast (Ie, in less than one second) Starting energy.

The intermediate circuit with its high voltage level (here 60 V or 350 V) supplies various auxiliary drives 29, such as A climate machine and servo drives, as well as various Heaters 30, such as engine and catalyst heaters With electrical energy. While such high-performance consumers Conventionally by mechanical coupling Driven by the internal combustion engine 1, or by the waste heat of the engine Combustion engine 1 can be heated Available high voltage level an efficiency Cheaper, purely electric drive.

A control device 31 passes through the inverter 17 Corresponding control of its semiconductor switches At any time, what amplitude, frequency, and phase The alternating voltage to be generated by it. The Control device 31, which is controlled, for example, by a corresponding Programmed microcomputer system Can determine, in a first step, the amount and the amount Direction of the torque which the electric machine 4 at a certain time. she can For example by means of a characteristic map control As the input information from the rotary transformer 16, the angle position Of the drive shaft 10, the instantaneous mean rotational speed And possibly further operating parameters, such as the throttle position, Is obtained. To start the combustion engine 1, the target torque can be based on stored Values ​​which determine the desired time course The speed or the torque of the electrical Machine 4 during the start-up process, supplemented if necessary By a measurement of these quantities and a feedback Which ensures compliance with the requirements. An energy consumption controller (not shown) is provided How much energy is needed to charge the vehicle battery 11, Supply of the low-voltage consumers 23 and the high-power consumers 29, 30 is required, so that the control device 31 a corresponding braking torque Can cause A motor controller 33 outputs to the controller 31, whether and to what extent the electrical Engine 4 additional vehicle accelerating or braking , So as to have a corresponding torque, For example for smoothing the torque characteristic curve of the internal combustion engine 1 (eg to fill a "turbo hole" at lower values Rotational speeds). Accordingly, one ASR control unit 34 (ASR = drive slip control) of the Control device 31 in the presence of drive slip, That the electric machine 4 is temporarily operated as a generator Brake, if necessary before the ASR control unit With remaining drive slip as a more massive measure Braking of the affected drive wheels by the Wheel brake. In addition, the ASR control unit Its slip information to the engine control unit 33, To a reduction in the internal combustion engine torque To cause. The engine controller 33 can be Also perform an automatic start-stop control and Of the control device 31, whether the electric machine 4 is to start the internal combustion engine 1.

The active reduction of rotational irregularities can be Are controlled in such a way that from a stored characteristic map The momentary rotational uniformity which is to be expected as a function of time From the above operating parameters. Another possibility is the actual Momentarily present rotational nonuniformity, Eg by calculating the instantaneous rotational speed On the basis of the signals supplied by the rotary transformer Information and / or by evaluating the current in the internal combustion engine 1, which are determined with the aid of Of gas pressure sensors 32, or by detection Of the instantaneous torque of the internal combustion engine 1 with the aid of a torque hub (not shown) in the drive train. A combination of regulation is also possible And control. From the thus determined value for the Momentary rotational uniformity becomes a corresponding (Antiphase) value for the rapidly varying target torque Of the electrical machine 4, which corresponds to the Braking (or possibly driving) constant torque Is superimposed.

In a second step, the control device 31, The amplitude, frequency and phase of the voltage or voltage Current from the inverter 17, So that the electric machine 4 can maintain this setpoint total torque . This determination is made with the electrical Asynchronous machine based on a field-oriented Which is based on a model calculation of the Electrical machine 4 and as input information Essentially the measurable electrical stator sizes (Amplitude, frequency and phase of current and voltage) and Uses the instantaneous average rotor speed or becomes From electrical quantities.

In FIG. 1, the control device 31 is configured as outside the Inverter housing 21. To be at the Boiling bath cooling, however, it is in others (Not shown) inside the Inverter housing 21.

The control device 31 can be various, to fulfill Their respective control tasks or derived therefrom Sensor information with the engine control unit 33 Control the combustion engine 1. It can be Eg around the rotary transformer 16 (angular position sensor), the Gas pressure sensors 32, sensors (not shown) for the Detection of the medium speed, load condition of the Combustion engine 1 (eg via the throttle position) And its torque (eg with the aid of a torque hub) act.

The energy gained by the additional functions by brakes Is temporarily stored in the additional memory 24 in order to switch to the Later driving of the electric machine 4 Or the vehicle battery 11.

FIGS. 2a-2c illustrate the generator operation Together with the additional function "active vibration damping". FIG. 2a shows the rotational speed (with the solid line) N of the crankshaft 10 as a function of the crankshaft angle Φ. The shaft rotates by a medium speed (here 3000 revolutions per minute) To smaller and larger rotational speeds, which in This idealized example as a whole Sinusoidal course. It is about The rotational irregularities resulting from the gas and mass forces, Which in this case is in the second order (ie Frequency of 100 Hz). For illustrative purposes, Also the angular interval required for one revolution of the shaft Is shown. Substantially proportional to the Rotational irregularities are fluctuations of the torque Mv of the internal combustion engine by an average torque. The Solid line in FIG. 2a thus also illustrates The course of the engine torque Mv as a function of the crankshaft angle Φ.

FIG. 2b shows the function of the electric machine 4 as a function Of the shaft angle φ, where In order to make the generator function more intuitive Is not yet shown Is. The course of the machine torque Me is essentially Opposite phase to non-uniformity Of the engine torque Mv. As a result, the rotational uniformity becomes - and the variation proportional to it Of the torque Mv - is substantially reduced, or it disappears Even practically, as in FIG. 2a by the broken line Line is illustrated.

In FIG. 2 b are the negative and positive torque terms Equal in size. The braking phase Is thus essentially equal to The energy to be applied during the following driving phase. The energy flow to the outside is therefore zero; Inside the system temporarily brake energy is temporarily stored. The system thus operates as shown in FIG. 2b as a pure rotational uniformity reducer Fast varying torque, without generator function.

FIG. 2c shows the superposition of both functions: the generator function Displaces the torque according to FIG. 2b globally To a certain amount ΔMe (the so-called stroke) into negative Direction. The stroke ΔMe varies slowly, in which Shown here, of approximately one revolution period It is constant in a good approximation. He is For the commonly required generator powers than the amplitude of the fast- en variation of the torque, So that the total torque Me is alternately positive And negative values. Averaged over the fast Torque variation gives a constant torque - ΔMe. The combustion engine is therefore mechanically averaged Energy which is converted into electrical energy And the system for charging the vehicle battery 11 and / or For operating electrical loads 23, 29, 30 becomes. With pure generator function without vibration damping The electric machine 4 produces a constant torque correspondingly Of the dash-dotted line ΔMe in FIG. 2c.

If, for example, during vehicle braking, the stroke ΔMe is greater than the Amplitude to reduce the rotational uniformity, The electric machine 4 only acts as a brake and No longer driving. The global torque profile can be Can also be displaced in the positive direction (positive stroke). The electrical machine then operates as a (driving) Engine, eg around the internal combustion engine at a vehicle acceleration to support.

By an appropriate adjustment of the (software) control The electrical machine - without any Constructive (hardware) changes - are small and very much Large generator power adjustable. Limiting only works The size of the electrical machine and the power electronics. This allows one and the same type of machine For example for small and large types of motor vehicles without Constructive adaptation.

The electrical machine 4 shown in more detail in FIG. 3 is Free of brushes or abrasives. they Has an outside diameter of about 300 mm and a Length in the axial direction of 70 mm and provides for one Weight of 10-15 kg a continuous torque of approx. 50 Nm and A peak torque of approx. 150 Nm. They can speed up Reaching the peak speeds of common combustion engines (About 6000 to 10,000 rpm) and is speed-resistant Up to 14000 rpm. The electric machine 4 has An externally mounted stator 8, which has grooves 35 in the direction Of the drive shaft 10 (axial direction). The stand 8 carries a three-phase winding 36, which is thus formed In that it is applied to three-phase current Twelve magnetic poles. Each pole has three grooves 35, a total of thirty-six grooves 35 are present. (at Other (not shown) Reduction of scattering effects per pole at least six, Preferably nine notches.) The poles run with the Phase AC oscillation in a circular motion in the stator 8 around. For a given time, their current position is By arrows indicating the reference characters "S" (for south pole) and "N" (for the North Pole). One of the grooves 35 To the outside, which extends in the circumferential direction The back part 37 is relatively thin in the radial direction Thickness (at the position of a groove 35), for example 3-25 mm. The stand 8 is made of thin stator plates (the Thickness is here 0.25 mm) made of a material with low Ummagnetisation losses (here less than 1 W / kg 50 Hz and a Tesla) with perpendicular to the axial direction Running sheet planes.

The internal rotor 9 is in the asynchronous machine As a squirrel-cage rotor with essentially axial direction Cage bars, each of which is provided on the end face with a Short circuit ring 38 are formed. At the The rotor 9 carries the same number of times Poles like the stand 8 (here twelve poles), which by permanent magnets Or correspondingly excited coils can be formed can. In FIG. 3, the synchronous machine is also illustrated, By the rotor poles present in it (Reference numeral 39) are schematically indicated. electricity to the Feeding the rotor winding (not shown), Poles is fed to the rotor via slip rings.

The air gap 40 between rotor 9 and stator 8 is relative big; Its width is 1 mm.

In other embodiments (not shown), the Runners on the outside and the stand inside.

In the embodiment according to FIG The clutch 5 is virtually completely integrated. Within the engine or gearbox housing, for example Non-rotatably supported stator 8, the rotor 9 is mounted on its Peripherals project on one side through an axially laterally projecting side Cage 54 with the drive shaft 10 of the internal combustion engine 1 Non-rotating. The rotor 9 is hollow on the inside and has an inner diameter Essentially the shape of a flat circular cylinder jacket. In the cavity is the clutch 5 - here as a driving clutch Acting multi-surface friction disc clutch - arranged. It can be a force closure Between the drive shaft 10 and the rotor 9, Which projects into the cavity, to the transmission 6. For this purpose, the rotor 9 is internally toothed and the Output shaft 55 is externally toothed in the region of the cavity 55. A disk pack 56 is arranged in the space therebetween, The disks 57 of which alternately externally and internally toothed , So that alternately one disk each with the rotor 9 (outer lamella 57a) and the next disc with the Output shaft 55 (inner lamina 57b) Is. Without axial pressure, the outer and inner lamellae can be used 57a, 57b rotate virtually freely against one another, the shafts 10, 55 are then uncoupled. Pressing the outer and inner lamellae 57a, 57b with the aid of a (not shown) (Eg, an angle lever) in the axial direction The resulting frictional forces make the Is formed between the shafts 10, 55, so that the From the internal combustion engine 1 and the electric machine 4 To the output shaft 55. Of the (Ie, the disk pack 56) of the clutch 5 takes place completely in the runner 9, so it protrudes Not in the axial direction laterally out of it. The Coupling 5 is designed as a wet clutch. The coupling oil Simultaneously serves to cool the electrical machine 4. Other embodiments (not shown) are different Switchable non-positive couplings, for example one Single disc coupling in dry or wet construction.

FIG. 5 shows a schematic circuit diagram of the inverter 17. The intermediate circuit storage 19 can be seen in FIG Shape of a capacity which corresponds to the (not shown) Additional memory 24 is connected in parallel. The Capacity symbolizes a parallel connection of several Capacitors.

The machine inverter 20 is controlled by three parallel-connected (But independently switchable) switch groups 42 , Each of the switch groups 42 for generating In each case one of the three three-phase voltages Dig. Each of the switch groups 42 is a series circuit Two (independently switchable) switches 43 between The positive and negative poles of the intermediate circuit. The Series circuit is centered (ie, between the switches 43) With one side of one of the three windings 36a, 36b, 36c of the three-phase winding 36; On the other Side, the three windings 36a, 36b, 36c are connected to each other connected.

A free-floating diode is connected in parallel with the switches 43 44. It is so poled that it is normal And only when the opposing switch is opened Is generated by a self- Short-term current flow in the device.

Each switch 43 symbolizes a parallel connection of Several (eg, five) MOS field effect transistors which are derived from Of the controller 31 to form a three-phase current Desired amplitude, frequency and phase directly To be controlled.

The DC / DC converter 18 comprises two sub-assemblies, Namely, one which receives electrical energy from the low Voltage level (12 V) to the high intermediate circuit voltage level (60 V and 350 V, respectively), and one Others, which - conversely - have electrical energy from the High voltage level (60 V or 350 V) to the low Voltage level (12 V). In embodiments With a vehicle battery arranged in the intermediate circuit, the The former subassembly is omitted.

For example, the first sub-assembly is A step-up actuator 45. This is controlled by a series circuit One with the positive terminal of the vehicle battery 11 Connected inductor 46 and a negative-pole inductor 46 connected to its negative pole And the negative pole of the intermediate circuit 47, wherein this series circuit is arranged centrally over a (Forward-biased) high-set-point diode 48 with the Positive pole of the intermediate circuit. When closed Off switch 47, a circulating current flows from the positive pole to the negative pole Of the vehicle battery 11. After opening the switch 47 A self-induction voltage seeks a breakdown Of this current, with the result that, for a short time The high DC link voltage level (350 V) is exceeded And current through the (otherwise blocking) step-up diode 48 and charges the intermediate circuit storage 19. By periodically opening and closing the switch 47, a quasi-stationary charge current, for example, is obtained Preparation of the start process. At switch 47, It is a semiconductor switch which is directly connected to the Control device 31 is controlled.

The second subassembly is, for example, a voltage reducer 49, which operates similarly to a switching power supply. He Comprises two series circuits of switches 50 between the Plus and minus poles of the intermediate circuit, each with Parallel-connected freewheeling diodes 51. The ends of a Primary winding of a high-frequency (RF) transformer 52 Are respectively connected to the centers of these series circuits. The secondary winding of the RF transformer 52 Supplies a rectifying and smoothing unit 53 which Again the vehicle battery 11 and possibly low-voltage consumer 23. The switches 50 symbolize Semiconductor switch, which is directly from the control device 31 are controlled. By periodic opening and A high-frequency alternating current can be connected to the switches Which is generated in the secondary winding of the HF transformer 52 has a corresponding alternating voltage Lower voltage level, which is determined by the Unit 53 is rectified and smoothed. The exact Value of the resultant DC voltage can be obtained by means of the aid The switch 50 is accurate by varying the switching frequency set to.

In embodiments with a synchronous machine is required In the generator mode, no actively controlled semiconductor switches, Here, a rectifier is sufficient Function voltage-controlled valves. With actively controlled Switches but higher performance is achieved.

The electric machine 4 according to FIG. 6, which additionally comprises The function of an electromagnetic clutch and / or Synchronizing means, has an inner and an inner surface, External electromagnetic action element, which is described in On the usual designations for electric machines Here the rotor 9 and the stator 8 '. Of the Rotor 9 is non-rotatably connected to, for example, the transmission 6 Coupled output shaft 55 and the stator 8 'is non-rotatable Connected to the drive shaft 10 (in others - not Shown, this assignment is reversed). The electric machine 4 is thus additionally connected to the electric machine 4 Rotation of rotor as a whole; The term "stand" That is to say, its rotatability only in one transmitted Meaning. While it is at a fixed Electrical machine - eg a rotating field machine - Is possible, the current supply to the fixed working element (Ie, the stand) and in the rotatable (Ie, in the rotor) currents without current supply only By induction, is expressed here, where both active elements - at least one of them (here The stator 8 ') current via rotary electrical connections (Eg via grinder / slip ring contacts not shown here) Respectively. The output shaft 55 is provided with A mechanical clutch, here one against the vehicle chassis Or the transmission housing Against rotation. The embodiment shown has No lock-up clutch, other embodiments (not shown) But with a frictional or frictional force Bridging clutch for mechanical connection Of the shafts 10, 55.

The electric machine 4 can be the internal combustion engine 1 Directly in abutment against the force determined by the brake 62 Start output shaft 55. The generator function By a permanently maintained clutch slip Is achieved.

In the additional function as a shift clutch and, if necessary, as a starting clutch (Apart from the slip for the generator function) A co-rotation of the shafts 10, 55 by one Such adjustment of the torque producing magnetic Fields of the engine 4 that rotational speed equilibrium between The waves 10,55. For an asynchronous machine This is achieved, for example, by the control Of the magnetic slip of a direction opposite to the driving torque direction Rotating field Frequency and amplitude.

Additional acceleration or deceleration is by generation Corresponding torques - or in other words - Smaller or larger clutch slip. The Electrical machine 4 can be incorporated into an ASR control system That if the drive wheel slip is too great, Clutch slip instantly increased and thus the The driving wheels is reduced.

A reduction of rotational irregularities of the drive shaft 10 can be supported in the stand of the vehicle Which were then fixed against rotation by means of the brake 62 Runner 9. Rotational irregularities can occur when driving By rapidly varying the transmitted Torque can be reduced by reduction And increase clutch slip.