Fault tolerant reluctance motor

0001The invention relates to an electrically commutated Motor, in particular switched reluctance motor, comprising two mutually movable base elements, namely a rotor and a stator, both of which each have a Plurality of Poland for cooperation with Poland of each having different base member, said pole at least one base element associated with each other in pairs and with electrically conductive windings for Application of a controlled electric current are provided and further comprising current control means, which are established for each pair of poles such that during operation, the windings on poles of a pair of each separate switching means that at least with are connected to a power source, while a common Control interval are energized while the windings of an adjacent pole pair together while a delayed control interval with Current are applied.

0002The invention further relates to a method for Driving an electrically commutated motor, in particular switched reluctance motor comprising two each movable base elements, namely a rotor and a stator, both of which each have a plurality of poles for interaction with the respective other poles of the base member , said poles of at least one base element associated with one another in pairs and with electrically conductive coils for applying a controlled electricity are provided, wherein for each pair of poles during operation, the windings on Poland a pair of each separate switching means which are connected with at least one current source, while a common control interval energized , while the windings of an adjacent pole pair together during a time shift control interval be energized.

State of the art

0003In safety-related applications, the fault tolerance is of electric motors is a decisive criterion. Especially in the modern motor vehicle is the use of electric motors even in security-related Applications and more popular. One example is the called "by wire" technology. For example, in a "steer by wire" system, no mechanical power transmission between the steering wheel and wheels more provided.

0004Rather, the wheel position by means of an electric motor due to electrical control commands of the driver changed. It is obvious that the error tolerance of the electric motor in such applications, a highly critical criterion.

0005To increase the fault tolerance are often redundant Systems used. For example, act two motors by a shaft so that loss of one engine where the second motor at least one emergency function is. Due to its dual interpretation of such redundant are However, systems in terms of cost, weight and Size disadvantage.

0006Another approach is the fault tolerance of Electric motor to raise itself. is an example of the reluctance motor disclosed in DE 40 08 606 A1. there If it is a motor, consisting of a Substantially cross-shaped rotor of a rotationally symmetrical facing stator with six inwardly Poland is provided. Each pole of the stator is provided with a Surrounded separate winding, so that the engine operates at suitable simultaneous actuation of the windings electric currents can be operated. two Poles of the stator are mutually diametrically opposite arranged. These are referred to as pole pairs will. The two windings of a pole pair each other are not electrically connected, but at separate switching means, namely inverters with three phases connected. The inverters are of Control means in response to engine movement, ie in particular its speed, angular position and intended direction of rotation, driven. The control of the inverter is performed so that the Windings each a pole pair at the same time, that is, during a common control interval, over the corresponding phase legs of the inverter are energized when a corresponding pair of poles the cross-shaped rotor is in its vicinity. at suitably chosen winding direction or current direction, results from flux linkage magnetic Flow through the rotor and stator, which on the rotor exerts a corresponding torque. Approaching the Rotor a symmetrical position to the energized Stator poles whose current supply is terminated and an adjacent Pole pair of the stator during a second Control interval energized.

0007By the independent circuit of the windings of a Pole pair two separate inverters, the operated rotating motor even in case of failure continues will. Under fault case is here the power outage in understood a winding, said power failure both damage the winding itself or damage in the corresponding portion of an inverter may be due. The of the pole pair applied with disturbed phase torque is then approximately half the size of the in regular operating mode applied.

0008More problematic is the situation is, however, when the engine is stopped. Thus, in particular at a 6/4 engine, i.e. an engine with six stator poles and four rotor poles positions conceivable in which a starting of the motor in case of failure is not possible and also not by asymmetric Overdriving of adjacent poles can be compensated. This is designed for safety-an intolerable State.

ADVANTAGES OF THE INVENTION

0009The invention, electrically commutated motor, in particular reluctance motor according to claim 1 is based on the Prior art in that the switching means are designed adapted to in case of a malfunction in the Winding a pole in addition to the loading of the remaining winding of the faulty pole pair windings an adjacent pair of poles each having a to apply electric current, one of said additional streams an opposite direction in the undisturbed Operating case reverse current direction has. This enables control of the motor according to the invention accordance with appropriate means of current control means To claim 2, so that the resulting magnetic flux in the engine, wherein the of the through superimposition induced currents in the individual windings applied Partial fluxes reveals substantially the same has shape as the magnetic flux in the undisturbed operating case. Therefore, the rotor on the substantially exerted same torque as in the undisturbed case. Of the Motor can thus start easily.

0010The method according to claim 10 is based on the prior art, characterized in that in case of failure the windings of an adjacent in the winding of a pole Pole pair additionally equipped with an electric Current are applied, wherein one of the additional Flows an opposite direction during normal operation case reverse current direction has. Such, Controlling the motor according to the invention has the advantage that the resulting magnetic flux, which is through superposition of the individual of the currents in the acted windings induced partial fluxes results, has substantially the same shape as the magnetic Flow during normal operation case.

0011The engine according to the invention is claimed in claim 3 in particularly configured favorably, as the use a full H-bridge circuit in a simple manner Current reversal in the controlled winding or the driven Windings allows. The same applies to the Embodiment of the method of claim 11th

0012The advantages of the reluctance motor according to the invention by Claim 4 or the advantages of the invention consist method of claim 12, especially that the basic power supply redundant is configured, resulting in a further increased security and fault tolerance contributes. According to claim 5, the in modern motor vehicles already present separate used Bordnetze to the aforementioned security increase to achieve redundancy, without the otherwise so associated cost and space disadvantages take have to.

0013The embodiment of claim 6 reflects the fact, that separate electrical systems in a motor vehicle usually have different voltages, in particular 14 volts and 42 volts. Had the windings a pole pair that different from vehicle electrical systems Voltage are fed, the same structure, this would at different magnetic fields at the poles of a Pair and so on to a radial force component the rotor lead. This would have an increased load of Rotor bearing and an uneven running of the engine. This is done by an interpretation of the individual windings compensated according to claim. 6

0014Although embodiments are also conceivable in which the Wraps of the poles of the rotor, is a Embodiment according to claim 7 particularly advantageous since In this way, the electrical contact of the windings simplified and the co-moved with the rotor weight thereby reducing the to overcome inertia becomes.

0015Further advantages of the invention result from the remaining Subclaims.

drawings

0016The inventions g is below with reference to the accompanying Drawings explained in more detail.

0017Show it<dl tsize="7"><dt>figure 1</dt><dd>a schematic diagram of a reluctance motor;</dd><dt>figure 2</dt><dd>four schematic diagrams of a reluctance motor in a critical angular position under different Bestromungsbedingungen and</dd><dt>figure 3</dt><dd>a block diagram.</dd></dl>

Description of Embodiments

00181 shows a schematic diagram of an electrically commutating the motor, the reluctance motor configured as 10 is. This is made up of an outer stator 11 and an inner rotor 12. The stator 11 has six poles S1a, S2a, S3a, S1b, S2b and S3b on. The A and B designated poles are otherwise the same reference numerals disposed diametrically opposite each other. on them are each electrically conductive windings, W1a, W2a, W3a, W1b, W2b and W3b. The rotor 12 comprises 4 Pole R1a, R2a, R1b, R2b. The designated with a and b Pole otherwise the same reference numerals are diametrically oppositely arranged. In fault-free Operation, during a first control interval, the Winding W1a on the stator pole S1a via a (not shown) first inverter with the Phase I energized. At the same time, the diametrically opposite Winding W1b on the stator pole S1b a separate, second inverter with the Phase I ' energized. The winding W2a on the stator pole S2a is during a second interval of the first control Inverter energized with the Phase II. simultaneously the winding W2b on the stator pole S2b via the second inverter with the Phase II 'energized. The Winding W3a on the stator pole S 3 during a third control interval on the first inverter energized with Phase III. The diametrically opposite Winding W3b on the stator pole S3b is simultaneously via the second inverter with the phase III ' energized. The triggering of the phases are measured using suitable Control means in dependence of the angular position of the rotor 12, the rotational speed and the intended Direction of rotation. The skilled person are a series of Embodiments of such control means known to the both electronic as well as an electric and / or mechanical devices may be executed.

00192a shows a simplified representation of the Reluctance motor 3 in a critical position of the rotor 12. When trouble-free operation, as illustrated in Figure 2a is, be in this position (not shown) Windings on the stator poles S1a and S1b with Phase I or I 'is energized. dashed shown is the resulting magnetic flux, through the poles S1a, R1a, R1b and S1b. In this constellation, it is easily possible that the embodiment shown in the Position standing rotor 12 in the described Energization starts.

0020However, there is a fault which the energization Stator pole S1b with the Phase I prevented ', resulting those shown in Figure 2b, shown in dashed lines magnetic fluxes over the poles S1a, R1a, R 2b and S3b or S1a, R1a, R2a and S3a. If the rotor 12 at rest, so that it does not by its inertia this critical position is carried away, prevented the illustrated magnetic flux image tarnishing of Motors from this position.

00212c shows the result of a control arrangement for the reluctance motor 10. If the inverter namely set up so that they are able, in addition for energizing the stator pole S1a with the phase I (in failed due to malfunction energization of the stator pole S1b with the Phase I '), the stator poles S3a and S3b oppositely to energize, ie the pole S3a with conventional Current direction and the pole S3b with a current direction to urge that the case in normal operation applied opposes, give the magnetic partial fluxes shown in Figure 2c. The dashed lines shown extending through energization with Phase I resulting partial flows according to Figure 2b. by broken shown are the partial flows, the off the energization of the invention the phase III and III ' where the minus sign, the reverse current direction of Phase III 'symbolizes.

00222d shows the composite part from the rivers of Figure 2c, resulting magnetic fluxes as solid lines. With suitably matched amperage resulting in substantially the same flux lines, as shown in Figure 2a, where the undisturbed operating case was shown. With this constellation, the Engine start easily even from a standstill.

0023In order to achieve the control of the present invention Reluctance motor, the inverter for each phase preferably provided with a full H-bridge circuit, in a reversal of the Bestromungsrichtung is capable.

0024Figure 3 illustrates the formation of the current source 20 as a DC power source 21 via switching means 23 having current control means 22 with the reluctance motor 10 is connected. The switching means 23 are preferred as the Inverter 24 is formed.

0025While the invention with particular reference to a shown and described preferred embodiment has been understood by those skilled in the art that changes may be made in form and detail, without departing from the spirit and scope of the invention. In particular, the number of the stator and / or Rotor poles vary, where a plurality, advantageously non-adjacent pole pairs in phase can be energized. Also, the relative constellation of rotor and stator can be modified within wide ranges, so that for example a central stator Orbiting, outer rotor can be realized. Accordingly to the disclosure of the present invention non-limiting. Instead, the disclosure of the present invention, the scope of the invention illustrate the in the following claims is set forth.

0026The foregoing description of embodiments according to the present invention serves only for illustrative Purposes and is not intended to limit the Invention. In the context of the invention are different Changes and modifications are possible without the scope the invention and its equivalents leave.