Method for operating a three-phase rotating electric machine and device for implementing the method

Technical field

0001The invention relates to the field of operating methods of three-phase rotating electrical machines. It is based on a method for operating a three-phase rotating electrical machine and on a device for carrying out the method according to the preamble of the independent claims.

State of the art

0002Devices for processes for operating three-phase rotating electrical machines are increasingly required and used today. A suitable device is for example in the<patcit id="pcit0001" dnum="EP1521356A2"><text>EP 1 521 356 A2</text></patcit> disclosed. A rotating electrical machine is specified therein, which has two sets of stator windings. Furthermore, an associated converter unit is provided for each stator winding set to feed it. For each of the converter units, an associated control device is provided for controlling the associated converter unit by means of a control signal. Furthermore, measuring means for measuring the currents of a stator winding set are provided, which measured currents are fed to the associated control device, this control device acting as a so-called "master", ie the measured currents of the "master" control device of the other control device, which is called a "follower" acts, pretends. The specification, ie the measured currents, is made via a data line. The "follower" control device then outputs a corresponding control signal to its associated converter device on the currents predetermined by the "master" control device, ie the control signal of the "follower" control device is dependent on the specification of the "master" control device, which one Default is a reference.

0003In the <patcit id="pcit0002" dnum="EP1732204A1"><text>EP 1 732 204 A1</text></patcit> A method for operating a rotating electrical machine is specified, in which method the respective stator winding set is fed by the associated converter unit. To enable redundant and independent regulation or influencing of electrical quantities of the individual stator winding sets of the rotating electrical machine, the currents of at least n-1 phase windings of each stator winding set are measured. An associated control device is provided for each converter unit, and each converter unit is controlled by means of a control signal from the associated control device independently of control devices of the other converter units. Furthermore, the control signal in the respective control device is formed from the measured currents of each stator winding set.

0004Furthermore, the two stator winding sets of the rotating electrical machine are in the <patcit id="pcit0003" dnum="EP1521356A2"><text>EP 1 521 356 A2</text></patcit> and at the <patcit id="pcit0004" dnum="EP1732204A1"><text>EP 1 732 204 A1</text></patcit> typically each connected in a star connection, the star connections of the stator winding sets with respect to one another having 30 degrees of electrical phase shift (designation: YY30). An undesirable phenomenon in such a rotating electrical machine is that, in particular, fifth and seventh stator current harmonics with respect to the stator current fundamental, but generally kth stator current harmonics with respect to of the stator current fundamental in both stator winding sets, where k = 6n +/- 1 and n = 1, 3, 5, .... These stator current harmonics have a negative effect and are therefore not acceptable.

Presentation of the invention

0005The object of the invention is therefore to specify a method for operating a three-phase rotating electrical machine which reduces the kth stator current harmonics with respect to the stator current fundamental in both stator winding sets of the rotating electrical machine, k = 6n +/- 1 and n = 1, 3, 5, ... is. Furthermore, a device is to be specified which can be implemented very simply, robustly and with little circuit complexity and with which the method for operation can be carried out in a particularly simple manner. These tasks are solved by the features of claims 1 and 7, respectively. Advantageous developments of the invention are specified in the dependent claims.

0006The three-phase rotating electrical machine has two stator winding sets, each stator winding set comprising three phase windings connected in star connection and the star connections of the stator winding sets to each other having 30 degrees of electrical phase shift and an associated converter unit being provided for each stator winding set. In the method according to the invention, the respective stator winding set is now fed by the associated converter unit, an associated control device being provided for each converter unit and each converter unit being controlled by means of a control signal from the associated control device independently of control devices from the other converter units. According to the invention, with respect to the respective control device, the control signal is generated in the control device by regulating the current torque value to a predeterminable reference torque value and by regulating the current stator flow value to a total reference stator flow value and, with respect to the respectively associated control device, the total reference stator flow value is formed from a predefinable reference stator flow value and from a differential stator flow value. wherein the differential stator flux value is calculated from the difference between a first stator flux value and a second stator flux value. The above-mentioned measures of the method according to the invention can advantageously reduce kth stator current harmonics with respect to the stator current fundamental in both stator winding sets of the rotating electrical machine, k = 6n +/- 1 and n = 1, 3, 5, ...

0007The device according to the invention for carrying out the method for operating a three-phase rotating electrical machine has an associated converter unit provided for each stator winding set for the supply and an associated control device provided for each converter unit for controlling the associated converter unit by means of a control signal independently of control devices of the respective other converter units . According to the invention, each control device now has a controller unit for regulating the associated current torque value to a specifiable reference torque value and for regulating the associated current stator flux value to a predefinable reference stator flux value, the control signal being present at the output of the regulator unit. Each control device also has a first calculation unit for forming the associated total reference stator flow value from a predeterminable reference stator flow value and from a differential stator flow value. In addition, each control device has a difference generator for calculating the associated differential stator flux value from the difference between a first stator flux value and a second stator flux value. The device according to the invention is therefore very simple, robust and can be implemented with little circuit complexity, and the method according to the invention can also be carried out particularly easily with the device according to the invention. The device according to the invention is constructed redundantly by the respective control device for controlling the associated converter unit independently of control devices of the other converter units in each case, as a result of which high availability and a high degree of serviceability of the overall system can be achieved. Furthermore, the device according to the invention for carrying out the method according to the invention by means of the control devices enables the kth stator current harmonics with respect to the stator current fundamental oscillation to be reduced in both stator winding sets of the rotating electrical machine, k = 6n +/- 1 and n = 1, 3, 5, .. .is.

0008These and other objects, advantages and features of the present invention will become apparent from the following detailed description of preferred embodiments of the invention in conjunction with the drawing.

Brief description of the drawings

0009Show it:<dl id="dl0001"><dt>Fig. 1</dt><dd>a first embodiment of a device according to the invention for carrying out the method according to the invention for operating a rotating electrical machine, in particular for a rotating electrical machine designed as a synchronous machine and</dd><dt>Fig. 2</dt><dd>an embodiment of a control device according to the device <figref idref="f0001">Fig. 1</figref> for a stator winding set and</dd><dt>Fig. 3</dt><dd>an embodiment of a control device according to the device <figref idref="f0001">Fig. 1</figref> for another stator winding set.</dd></dl>

0010The reference symbols used in the drawing and their meaning are summarized in the list of reference symbols. In principle, the same parts are provided with the same reference symbols in the figures. The described embodiments are examples of the subject matter of the invention and have no restrictive effect.

Ways of Carrying Out the Invention

0011In <figref idref="f0001">Fig. 1</figref> 1 shows a first embodiment of a device according to the invention for carrying out the method according to the invention for operating a three-phase rotating electrical machine 1, in particular for a rotating electrical machine 1 designed as a synchronous machine. The machine 1 has two stator winding sets A, B, each stator winding set A, B comprising three phase windings connected in a star connection and the star connections of the stator winding sets A, B having 30 degrees of electrical phase shift with respect to one another and an associated converter unit 2 for each stator winding set A, B , 13 is provided. The respective stator winding set A, B is fed by the associated converter unit 2, 13. In terms of the method, an associated control device 3A, 3B is provided for each converter unit 2, 13, each converter unit 2, 13 being controlled independently of control devices 3A, 3B of the respective other converter units 2, 13 by means of a control signal SA, SB of the associated control device 3A, 3B .

0012According to the invention, the control signal SA, SB in the control device 3A, 3B is now regulated in the control device 3A, 3B by regulating the current torque value M_isA, M_{is B} to a predeterminable reference torque value M_refA, M_refB and by adjusting the current stator flux value ψ_isA ψ_{is B} to a total reference stator flow value ψ_{ref, gesA}, ψ_{ref, tot} generated and again with respect to the respective control device 3A, 3B the total reference stator flux value ψ_{ref, gesA}, ψ_{ref, tot} from a predeterminable reference stator flux value ψ_refA, ψ_refB and from a differential stator flow value ψ_εA, ψ_εB formed, the differential stator flux value ψ_εA, ψ_εB from the difference of a first stator flux value ψ_1A, ψ_1B and a second stator flux value ψ_2A, ψ_{2 B} is calculated. The aforementioned measures of the method according to the invention can advantageously reduce kth stator current harmonics with respect to the stator current fundamental in both stator winding sets A, B of the rotating electrical machine 1, where k = 6n +/- 1 and n = 1, 3, 5, ... is.

0013The first stator flux value ψ becomes procedural with respect to the respective control device 3A, 3B_1A, ψ_1B preferably from the DC voltage U_DCA, U_DCB of a capacitive energy store 12, 14 connected to the respectively associated converter unit 2, 13 according to <figref idref="f0001">Fig. 1</figref>, from a first stator current i_1A, i_1B of the associated stator winding set A, B and from a second stator current i_2A, i_{2 B} of the associated stator winding set A, B, in particular according to a voltage model. Furthermore, with respect to the respective control device 3A, 3B, the second stator flux value ψ_2A, ψ_{2 B} from the first stator current i_1A, i_1B of each stator winding set A, B and from the second stator current i_2A, i_{2 B} of each stator winding set A, B, in particular according to a current model.

0014The currents i_1A, i_1B, i_2A, i_{2 B} of the three phase windings of each stator winding set A, B are according to <figref idref="f0001">Fig. 1</figref> measured using measuring means 4A, 4B. Through the stator flux values ​​ψ thus formed_1A, ψ_1B, ψ_2A, ψ_{2 B} and the resulting differential stator flux value daraus_εA, ψ_εB the above-mentioned k-th stator current harmonics with regard to the stator current fundamental in both stator winding sets A, B of the rotating electrical machine 1 can be reduced in a very simple manner.

0015In the case of a three-phase rotating electrical machine 1 designed as a synchronous machine with respect to the respective control device 3A, 3B, the second stator flux value ψ_2A, ψ_{2 B} additionally from the rotor position ϕA, ϕB (magnet wheel position) and from the excitation current i_E educated. If there is no excitation winding, for example in the case of a permanent magnet-excited synchronous machine, no excitation current i_E for the formation of the second stator flux value ψ₂ needed. It should be mentioned that the rotor position ϕA, ϕB can be measured or is a calculated quantity. The excitation current i_E and the DC voltage U_DCA, U_DCB of the respective capacitive energy store 12, 14 are measured quantities.

0016Furthermore, in the case of a three-phase rotating electrical machine 1 designed as a synchronous machine, the total reference stator flow value ψ with respect to the respective control device 3A, 3B_{ref, gesA}, ψ_{ref, tot} additionally formed from a correction value WA, WB, the correction value WA, WB from the predeterminable reference stator flow value ψ_refA, ψ_refB, from the predeterminable reference torque value M_refA, M_refB, depends on the rotor frequency w or the stator frequency w.

0017The correction value W in general, ie without the indexing of the variables used with respect to the stator winding sets A, B, is formed using the following formula <maths id="math0001"><math display="block"><mi mathvariant="normal">W</mi><mfenced><mi mathvariant="normal">ω</mi><mo>⁢</mo><msub><mi mathvariant="normal">M</mi><mi>ref</mi></msub><mo>⁢</mo><msub><mi mathvariant="normal">ψ</mi><mi>ref</mi></msub></mfenced><mo mathvariant="normal">=</mo><mrow><mo mathvariant="normal">{</mo><mtable columnalign="left"><mtr><mtd><msup><mfenced><mn mathvariant="normal">1</mn><mo mathvariant="normal">-</mo><mfrac><mi mathvariant="normal">ω</mi><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mfrac></mfenced><mn mathvariant="normal">2</mn></msup><mo mathvariant="normal">⋅</mo><mfenced><mn mathvariant="normal">1</mn><mo mathvariant="normal">+</mo><mfrac><msub><mi mathvariant="normal">M</mi><mi>ref</mi></msub><msub><mi mathvariant="normal">M</mi><mi>Max</mi></msub></mfrac></mfenced></mtd><mtd><mi mathvariant="normal">ω</mi><mo mathvariant="normal"><</mo><mi mathvariant="normal">p</mi><mo mathvariant="normal">⋅</mo><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mtd></mtr><mtr><mtd><msup><mfenced><mn mathvariant="normal">1</mn><mo mathvariant="normal">-</mo><mfrac><mrow><mi mathvariant="normal">p</mi><mo mathvariant="normal">⋅</mo><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mrow><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mfrac></mfenced><mn mathvariant="normal">2</mn></msup><mo mathvariant="normal">⋅</mo><mfenced><mn mathvariant="normal">1</mn><mo mathvariant="normal">+</mo><mfrac><msub><mi mathvariant="normal">M</mi><mi>ref</mi></msub><msub><mi mathvariant="normal">M</mi><mi>Max</mi></msub></mfrac></mfenced></mtd><mtd><mi mathvariant="normal">p</mi><mo mathvariant="normal">⋅</mo><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub><mo mathvariant="normal"><</mo><mi mathvariant="normal">ω</mi><mo mathvariant="normal"><</mo><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mtd></mtr><mtr><mtd><msup><mfenced><mn mathvariant="normal">1</mn><mo mathvariant="normal">-</mo><mfrac><mrow><mi mathvariant="normal">p</mi><mo mathvariant="normal">⋅</mo><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mrow><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mfrac></mfenced><mn mathvariant="normal">2</mn></msup><mo mathvariant="normal">⋅</mo><mfenced><mn mathvariant="normal">1</mn><mo mathvariant="normal">+</mo><mfrac><msub><mi mathvariant="normal">M</mi><mi>ref</mi></msub><msub><mi mathvariant="normal">M</mi><mi>Max</mi></msub></mfrac></mfenced><mo mathvariant="normal">⋅</mo><msup><mfenced><mfrac><msub><mi mathvariant="normal">ψ</mi><mi>nom</mi></msub><msub><mi mathvariant="normal">ψ</mi><mi>ref</mi></msub></mfrac></mfenced><msub><mi mathvariant="normal">k</mi><mn mathvariant="normal">2</mn></msub></msup></mtd><mtd><mi mathvariant="normal">ω</mi><mo mathvariant="normal">></mo><msub><mi mathvariant="normal">ω</mi><mi>nom</mi></msub></mtd></mtr></mtable></mrow></math><img file="EP2001123B1_D0001.tif" /></maths>where ω is the rotor frequency or the stator frequency, ω_nom the associated nominal rotor frequency or the nominal stator frequency, M_Max the maximum permissible torque, ψ_nom the nominal stator flux, p a first adjustable weighting parameter and k₂ is a second adjustable weighting parameter. The formation of the total reference stator flow value ψ_{ref, sat} then takes place, also without the indexing of the variables used with respect to the stator winding sets A, B, according to the following formula <maths id="math0002"><math display="block"><msub><mi mathvariant="normal">Ψ</mi><mrow><mi>ref</mi><mo>,</mo><mi>total</mi></mrow></msub><mo>=</mo><mfenced><msub><mi mathvariant="normal">Ψ</mi><mi>ε</mi></msub><mo>⋅</mo><mfenced><mn>1</mn><mo>-</mo><mi mathvariant="normal">W</mi></mfenced></mfenced><mo>+</mo><msub><mi mathvariant="normal">Ψ</mi><mi>ref</mi></msub></math><img file="EP2001123B1_D0002.tif" /></maths>

0018With respect to the respective control device 3A, 3B, the current stator flux value ψ_isA, ψ_{is B} also from the first stator flux value ψ_1A, ψ_1B, from the second stator flux value ψ_2A, ψ_{2 B}, from the differential stator flow value ψ_εA, ψ_εB and formed from the correction value WA, WB. Furthermore, with respect to the respective control device 3A, 3B, the current torque value M_isA, M_{is B} from the current stator flux value ψ_isA, ψ_{is B}, from the first stator current i_1A, i_1B of the associated stator winding set A, B and from the second stator current i_2A, i_{2 B} of the associated stator winding set A, B.

0019According to <figref idref="f0001">Fig. 1</figref> The device according to the invention for carrying out the method according to the invention described in detail above comprises in each case an associated converter unit 2, 13 provided for each stator winding set A, B and in each case an associated control device 3A, 3B provided for each converter unit 2, 13 for controlling the associated converter unit 2, 13 by means of the control signal SA, SB independently of control devices 3A, 3B of the respective other converter units 2, 13. According to the invention, each control device 3A, 3B according to one in <figref idref="f0002">Fig. 2</figref> and <figref idref="f0003">Fig. 3</figref> Shown embodiment of the control device 3A, 3B, in particular with respect to an associated stator winding set A, B, according to the device <figref idref="f0001">Fig. 1</figref> a controller unit 11 for controlling the associated current torque value M_isA, M_{is B} to the predefinable reference torque value M_refA, M_refB and to regulate the associated current stator flux value ψ_isA, ψ_{is B} to the predeterminable reference stator flux value ψ_ref, _total, ψ_{ref, tot} on, the control signal SA, SB being present at the output of the controller unit 11. In addition, each control device 3A, 3B has a first calculation unit 8 for forming the associated overall reference stator flow value ψ_{ref, gesA}, ψ_{ref, tot} from the specifiable reference stator flux value wert_refA,ψ_refB and from a differential stator flow value ψ_εA, ψ_εB , each control device 3A, 3B also having a difference former 7 for calculating the associated differential stator flow value ψ_εA, ψ_εB from the difference of the first stator flux value ψ_1A, ψ_1B and the second stator flux value ψ_2A, ψ_{2 B} having. The device according to the invention is thus extremely simple in construction and implementation and very robust, and the method according to the invention can also be carried out particularly easily with the device according to the invention. The device according to the invention is constructed redundantly by the respective control device 3A, 3B for controlling the respectively associated converter unit 2, 13 independently of control devices 3A, 3B of the respective other converter units 2, 13, which results in high availability and a high degree of maintenance friendliness of the overall system. In addition, the device according to the invention for carrying out the method according to the invention by means of the control devices 3A, 3B enables the kth stator current harmonics with respect to the stator current fundamental oscillation in both stator winding sets A, B of the rotating electrical machine 1 to be reduced, where k = 6n +/- 1 and n = 1 , 3, 5, ... is.

0020According to <figref idref="f0002">Fig. 2</figref> and <figref idref="f0003">Fig. 3</figref> each control device 3A, 3B preferably has a second calculation unit 5 for forming the associated first stator flux value ψ_1A, ψ_1B from the DC voltage U_DCA, U_DCB the capacitive energy store 12, 14 connected to the associated converter unit 2, 13, from the first stator current i_1A, i_1B of the associated stator winding set A, B and from the second stator current i_2A, i_{2 B} of the associated stator winding set A, B. Furthermore, each control device 3A, 3B according to<figref idref="f0002">Fig. 2</figref> and <figref idref="f0003">Fig. 3</figref> advantageously a third calculation unit 6 for forming the associated second stator flux value ψ_2A, ψ_{2 B} from the first stator current i_1A, i_1B of each stator winding set A, B and from the second stator current i_2A, i_{2 B} of each stator winding set A, B.

0021In each control device 3A, 3B in the case of a three-phase rotating electrical machine 1 designed as a synchronous machine, the third calculation unit 6 forms the associated second stator flux value fluss_2A, ψ_{2 B} additionally from the rotor position ϕA, ϕB and from the excitation current i_E , where the rotor position ϕA, ϕB and the excitation current i_E is fed to the third calculation unit 6, in particular as in <figref idref="f0002">Fig. 2</figref> and <figref idref="f0003">Fig. 3</figref> shown.I

0022Furthermore, in the case of a control device 3A, 3B, in the case of a three-phase rotating electrical machine 1 designed as a synchronous machine, the first calculation unit 8 forms the associated total reference stator flux value ψ_{ref, gesA}, ψ_{ref, tot} additionally from a correction value WA, WB, the correction value WA, WB from the predeterminable reference stator flow value ψ_refA, ψ_refB, from the predeterminable reference torque value M_refA, M_refB, depends on the rotor frequency w or the stator frequency w and the predeterminable reference stator flux value Ψ_refA, Ψ_refB, the predefinable reference torque value M_refA, M_refB, the rotor frequency w or the stator frequency w of the first calculation unit 8 is supplied. The formation of the respective correction value WA, WB according to the above-mentioned associated formula in general for the correction value W and the formation of the respective total reference stator flow value ψ_{ref, gesA}, ψ_{ref, tot} according to the above-mentioned associated formula in general for the total reference stator flow value ψ_{ref, sat} is advantageously carried out in the first calculation unit 8.

0023According to <figref idref="f0002">Fig. 2</figref> and <figref idref="f0003">Fig. 3</figref> each control device 3A, 3B has a fourth calculation unit 9 for forming the associated current stator flux value ψ_isA, ψ_{is B} from the first stator flux value ψ_1A, ψ_1B, from the second stator flux value ψ_2A, ψ_{2 B}, from the differential stator flow value ψ_εA, ψ_εB and from the correction value WA, WB. In addition, each control device 3 has a fifth calculation unit 10 for forming the associated current stator flux value ψ_isA, ψ_{is B} from the first stator flux value ψ_1A, ψ_1B, from the second stator flux value ψ_2A, ψ_{2 B}, from the differential stator flow value ψ_εA, ψ_εB and from a correction value WA, WB.

Reference list

0024<dl id="dl0002" compact="compact"><dt>1</dt><dd>three-phase rotating electrical machine</dd><dt>2, 13</dt><dd>Converter unit</dd><dt>3A, 3B</dt><dd>Control device</dd><dt>4A, 4B</dt><dd>Measuring equipment</dd><dt>5</dt><dd>second calculation unit</dd><dt>6</dt><dd>third calculation unit</dd><dt>7</dt><dd>Difference</dd><dt>8</dt><dd>first calculation unit</dd><dt>9</dt><dd>fourth calculation unit</dd><dt>10</dt><dd>fifth calculation unit</dd><dt>11</dt><dd>Controller unit</dd><dt>12, 14</dt><dd>capacitive energy storage</dd><dt>A, B</dt><dd>Stator winding sets of the rotating electrical machine</dd></dl>