DE102018203355A1 - CONTROL SYSTEM FOR AN INDUCTION MACHINE AND ELECTRIC VEHICLE - Google Patents

Abstract

[Article] To provide a control system for an induction machine capable of driving two rotors properly even during cornering: [solution] A control system for an induction machine is disclosed. The control system comprises as ECU a ECU (5). The ECU (5) calculates target torques for the respective two rotors (22, 23) disposed on both sides of a stator (21) of a motor (2) due to a torque distribution between the two rotors and a total torque to be generated by the motor (2) ; and selects, as a frequency for the synchronous speed of the motor (2), a drive frequency common to the two rotors (22, 23) based on the target torques and the speeds of the respective two rotors (22, 23).

Description

[Technical area]

The present invention relates to a control system for an induction machine.

[Background of the technique]

In the following referred to as Patent Literature 1 JP 2827502 B2 describes an electric vehicle with an induction machine, which is driven by a drive source by an AC voltage. In order to reduce the weight of the powertrain in the electric vehicle by using a twin-rotor induction machine as the differential gear, the induction machine is controlled by a single inverter to perform drive control of both the left and right drive wheels.

Specifically, a voltage is determined based on an average corresponding to the sum of the rotational speed of a rotor for the left driving wheel and the rotational speed of the other rotor for the right driving wheel divided by two. Based on the determined voltage, one of different torque / slip curves is selected. The torque is determined by querying the selected torque / slip curve.

In order to prevent the occurrence of undesired turning ability during cornering, a target torque of the rotor for the inside drive wheel and a target torque of the outside drive wheel are determined after the synchronous speed of the induction machine is updated to increase the synchronous speed has been so that the torque of the rotor for the outer drive wheel is greater than the torque of the rotor for the inner drive wheel.

In addition, to offer the same ride feel during acceleration during cornering, such as during straight-ahead driving, the tension is reduced to change the torque / slip curve to a new curve such that the average, which is the sum of the rotor's internal torque Drive wheel and the torque of the rotor for the outer drive wheel, divided by two, corresponds to the torque for driving straight ahead, which is determined by querying the selected torque / slip curve.

[State of the art]

[Patent Literature]

Patent Literature 1: JP 2827502 B2

Summary of the Invention

[Technical task]

In a case where, as in JP 2827502 B2 is described, the synchronous speed of the induction machine based on the average, which is equal to the sum of the speeds of the left and right rotor is determined, it is likely that the speed of the rotor for the outer drive wheel when cornering at high speed exceeds the synchronous speed of the induction machine , As a result, the torque of the outer drive wheel rotor, which is determined by interrogating the selected torque / slip curve, assumes a minus value so that the outer drive wheel rotor generates regenerative torque. This complicates smooth cornering of the vehicle.

The object of the present invention is to provide a control system for an induction machine capable of properly driving two rotors even when cornering.

[Solution of the task]

There is provided a control system for an induction machine comprising two rotors capable of rotating at different speeds. The control system comprises: a control unit. The control unit calculates target torques for the two rotors, respectively, based on a torque distribution between the two rotors and a total torque to be generated by the induction machine. In addition, the control unit selects a common drive frequency of the two rotors as a frequency of the synchronous speed of the induction machine, based on the target torques and the speeds of the corresponding two rotors.

[Advantageous Effects of Invention]

As a result, the two rotors according to the invention are driven properly even when cornering.

list of figures

• 1 is a schematic representation of an embodiment of a control system for an induction machine.
• 2 is a perspective view of a stator of the induction machine.
• 3 is a perspective view of two rotors of the induction machine.
• 4 is a sectional view of the induction machine.
• 5 shows a vehicle while cornering.
• 6 shows an exemplary torque / slip map.
• 7 FIG. 10 is a block diagram illustrating control of the control system. FIG.
• 8th shows a change in the torque / slip map performed in the control system.

[Embodiment of the Invention]

In the present, there is disclosed a control system for an induction machine comprising two rotors capable of rotating at different speeds. The control system comprises: a control unit. The control unit computes target torques for the two respective rotors based on a torque distribution between the two rotors and a total torque to be generated by the induction machine. In addition, the control unit selects a common drive frequency of the two rotors as a frequency of the synchronous speed of the induction machine, based on the target torques and the speeds of the corresponding two rotors.

As a result, the two rotors according to the invention are driven properly even when cornering.

[Embodiments]

In the following, it will be described in detail with reference to the accompanying drawings how to control an induction machine in the present embodiment.

In 1 denotes the reference numeral 1 generally a vehicle 1 in the form of an electric vehicle. The vehicle 1 includes: an induction machine 2 that works as a traction motor; an inverter 3 ; a battery 4, and a control unit in the form of an electronic control unit (ECU) 5 ,

The induction machine 2 includes an annular stator 21 , a first disk-shaped rotor 22 and a second disc-shaped rotor 23 , The first and second rotor 22 and 23 are rotatable about an axis and on both sides of the stator 21 arranged. In detail, the first rotor 22 by an axial distance from an axial end surface of the stator 21 axially spaced, and the second rotor 23 is at a different axial distance from the other axial end surface of the stator 21 axially spaced.

One side of the first rotor 22 lies the stator 21 opposite, and the other side faces the one side. From the opposite side of the first rotor 22 extends a first output shaft 24. The first output shaft 24 is a rotary shaft of the first rotor 22 rotatable.

The first output shaft 24 is connected to a left drive wheel 61. The left drive wheel 61 rotates together with the first rotor 22 ,

One side of the second rotor 23 lies the stator 21 opposite and the other side faces the one side. From the opposite side of the second rotor 23, a second output shaft 25 extends. The second output shaft 25 is a rotary shaft of the second rotor 23 rotatable.

The second output shaft 25 is connected to a right drive wheel 62. The right drive wheel 62 rotates together with the second rotor 23 , The first and the second rotor 22 and 23 can each be connected to the first and second output shafts 24 and 25 via gears.

The first output shaft 24 and the second output shaft 25 are not directly connected, so that the first and second output shafts 24 and 25 can rotate at independent speeds. In the present embodiment, the respective axes of rotation of the first and second rotors are aligned 22 and 23 with the center line of the stator 21 ,

Referring to the 2 includes the stator 21 an annular stator core 211 and one in the stator core 211 arranged stator winding 212 , The stator core 211 is made of a magnetic material.

The stator core 211 includes an annular stator yoke (not shown) and a plurality of circumferentially spaced stator teeth 213 ,

In the specification, the term "circumferential direction" and its derivatives refer to the circumferential direction with respect to the center axis of the stator 21 , In addition, the term "axial Direction "and its derivatives, the axial direction along the central axis of the stator 21 ,

Further, the term "radial direction" and its derivatives designate one of the directions along the lines crossing the central axis at right angles. In other words, the radial directions denote the directions extending radially from the central axis. The term "outside in the radial direction" refers to the side remote from the central axis. The term "inside in the radial direction" refers to a side that is radially near or less distant from the center axis.

The stator teeth 213 extend outward from the stator yoke. As seen in the axial direction, each of the stator teeth forms 213 a trapezoid. As seen in the circumferential direction, the stator tooth 213 a rectangular cross-sectional profile. In the present embodiment, the stator teeth 213 , which are in a number of thirty-six (36), evenly distributed in the circumferential direction of the stator yoke.

The stator winding 212 is toroidal about the annular stator yoke, using between each two adjacent stator teeth 213 formed columns, wound. The toroidal winding refers to the winding of a wire on the stator yoke to form a toroid.

With the toroidal winding, it is possible to arrange the coil ends concentrically on the inside in the radial direction, resulting in the reduction of the induction machine 2 contributes. By arranging the coil ends concentrically on the inside in the radial direction, it is possible to arrange heat paths on the outside in the radial direction, thereby improving the heat dissipation.

The stator winding 212 is a three-phase winding having a U-phase, a V-phase and a W-phase. The stator winding 212 is formed by winding a wire on the stator yoke to form a toroid. With the toroidal winding, the coil ends are concentric on the inner side in the radial direction, so that a distribution winding is provided solely by a circuit of the connection between the respective coil ends.

Referring to the 3 points the first rotor 22 a squirrel-cage structure having a rotor core 221 and rotor busbars 222 includes. On the stator 21 opposite surface of the rotor core 221 are rotor teeth 223 intended. The rotor teeth 223 protrude from the rotor core 221 in the axial direction. In the axial direction of the rotor teeth 223 seen, is each of the rotor teeth 223 a trapezoid. The rotor teeth 223 are circulating and evenly distributed. In the present embodiment, the rotor teeth are 223 whose number is forty (40), circulating and evenly distributed.

The rotor bars 222 are on the entire surface of the rotor core 221 that with the rotor teeth 223 is formed, surface mounted. The rotor bars 222 consist for example of copper or aluminum. The rotor bars 222 expose the tip end surfaces of each of the rotor teeth and thus expose them. In this way, the first rotor 22 is formed as a cage rotor.

The second rotor 23 has a squirrel cage type structure comprising a rotor core 231 and rotor bus bars 232 includes. Like the rotor 22 are in 3 invisible rotor teeth on the stator 21 opposite surface of the rotor core 221 intended.

As with the first rotor 22 are the rotor bars 232 are on the entire surface of the rotor core 231 connected to the rotor teeth of the rotor core 231 is formed, surface mounted. In this way, the second rotor 23 designed as cage rotor.

The first rotor 22 and the second rotor 23 have the same structure (in terms of the number of slots, the formation of the rotor cores and the resistance of the rotor bars).

As in 4 can be seen, the stator is located 21 between the first and the second rotor 22 and 23 to provide a double-rotor axial flow induction machine. The axial flow induction machine has the configuration of a double-sided axial air gap induction machine in which the stator 21 from the first and the second rotor 22 and 23 is spaced, so that a predetermined Axialluftspalt is formed.

Through the stator winding 212 supplied three-phase stator magnetization alternating currents, a rotating magnetic field is generated. Into the rotor bars 222 of the first rotor 22 and the rotor bars 232 of the second rotor 23 voltages are induced, and the rotor bars 222 and 232 be shorted. In the rotor bars 222 and 232 flow currents (or induced currents). The torque of the first rotor 22 is due to the interaction between the rotating magnetic field and the rotor currents in the rotor bars 222 while the torque of the second rotor 23 from the interaction between the rotating magnetic field and the rotor currents in the rotor bars 232 comes. The rotor currents are due to the flux density (or flux linkages) and the induced relative speed (ω _s - ω ₀ ), where: ω _{s is} the synchronous speed, and ω _{0 is} the speed of a rotor. In this way, the induction machine 2 functions like an induction motor.

Referring again to 1 , the inverter converts 3 the direct current of the battery in three-phase alternating powers and this leads, during the motor mode or during the drive mode, the stator winding 212 to. During the regeneration mode, the inverter converts 3 the three-phase alternating powers (AC) of the stator winding 212 in DC (DC) and charges the battery 4.

The battery 4 may be a nickel battery or a lithium battery and includes a plurality of cells connected in series. The battery 4 feeds power to the induction machine 2 via the inverter 3 ,

The ECU 5 includes a computer unit. The computer unit comprises a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), a flash memory for data backup, input channels and output channels.

The ROM of this computer unit stores programs by which this computer unit performs the function of the ECU 5 met, as well as different constants and different maps. In other words, in the present embodiment, these components of the computer unit function as the ECU 5 due to the execution of the programs stored in the ROM by the CPU.

Various sensors are connected to the input channels of the ECU 5 connected. These sensors include: an accelerator pedal position sensor 71; a brake hydraulic pressure sensor 72; a steering angle sensor 73; a vehicle speed sensor 74; an angular velocity sensor 75; a wheel speed sensor 76 for the left drive wheel 61 and a wheel speed sensor 77 for the right drive wheel 62.

The accelerator pedal position sensor 71 detects an accelerator pedal position of a not-shown accelerator pedal. The accelerator pedal is operated by the vehicle operator (or driver).

The brake hydraulic pressure sensor 72 provides, as sensor information, a voltage signal indicative of the brake pressure applied during or during a brake application. The voltage signal increases as the brake pedal is depressed. The ECU 5 determines a control input of the brake pedal based on the sensor information of the brake hydraulic pressure sensor 72.

The steering angle sensor 73 detects a steering angle or a position of a steering wheel, not shown. The vehicle speed sensor 74 detects a vehicle speed at which the vehicle 1 moves. The angular velocity sensor 75 detects a yaw rate about a vertical axis passing through the center of gravity of the vehicle 1 leads, and a lateral acceleration of the vehicle 1 is suspended.

The wheel speed sensor 76 detects a rotational speed of the first output shaft 24 which is connected to the left drive wheel 61. The wheel speed sensor 77 detects the rotational speed of the second output shaft 25 which is connected to the right drive wheel 62.

Various types of targeting instruments are associated with the output channels of the ECU 5 connected. The various targeting instruments include an inverter 3 ,

The ECU 5 calculates a total target torque for the left drive wheel 61 and the right drive wheel 62 based on a power demand signal of the accelerator pedal position sensor 71 and a brake demand signal of the brake hydraulic pressure sensor 72. The ECU 5 calculates a target torque for the left drive wheel 61 and a target torque for the right drive wheel 62 based on the total target torque. The ECU 5 calculates a frequency of the fundamental magnetic rotating field, often called "driving frequency", and phase current control values for driving the motor 2 based on a target torque for the left drive wheel 61, a target torque for the right drive wheel 62, a rotational speed of the left drive wheel 61, a rotational speed of the right drive wheel 62, and a selected torque / slip (characteristic) curve. The ECU 5 controls the inverter 3 due to the specific drive frequency and the phase current control values, so the inverter 3 the engine 2 drives.

The ECU 5 determines whether there is a request for cornering based on an input of the steering angle sensor 73, and calculates a drive frequency (ie, a frequency of the fundamental magnetic rotating field) and phase current control values for driving the motor in response to the request 2 for torque distribution for smooth cornering of the vehicle 1 are appropriate. For example, the ECU 5 determine that there is a request for cornering when the steering angle detected by the steering angle sensor 73 exceeds a predetermined value.

Referring to the 5 , calculates the ECU 5 a target yaw rate γ * in the vehicle 1 and a target lateral acceleration A _y * im vehicle 1 based on various inputs, comprising: a rotational speed n ₁ of the first rotor coupled to the left drive wheel 61 22 , a rotational speed n ₂ of the second rotor coupled to the right drive wheel 62 23 , a power demand K _a (from the accelerator position sensor 71), a brake demand K _b (from the brake hydraulic pressure sensor 72), a steering angle δ (from the steering angle sensor 73), a vehicle speed V (from the vehicle speed sensor 74), a yaw rate γ (from the angular velocity sensor 75) Yaw motion around the center of gravity G of the vehicle 1 leading yaw axis, and a lateral acceleration A _y (from the angular velocity sensor 75).

The ECU 5 determines a target yaw rate γ * and a target lateral acceleration A _y *, for example, by resorting to a map with the various inputs mentioned above.

The ECU 5 calculates a target yaw moment M _r * about the center of gravity G of the vehicle derived from a torque difference ΔT between the left drive wheel torque T ₁ and the right drive wheel torque T ₂ 62 1 , due to the target yaw rate γ * and the target lateral acceleration A _y *.

During cornering, which causes a difference between a rotational speed of the left drive wheel 61 and a rotational speed of the right drive wheel 62, the calculated target yaw moment M _r * is aligned in the same direction as the direction in which the yaw rate γ is aligned when For example, the lateral acceleration A _{y is} less than the target lateral acceleration A _y * or when the yaw rate γ is less than the target yaw rate γ *.

During cornering, the calculated yaw moment M _r * is oriented in the opposite direction to the direction in which the yaw rate γ is aligned, for example, when the lateral acceleration A _{y is} greater than the target lateral acceleration A _y * or when the yaw rate γ is greater is the target yaw rate γ *.

The ECU 5 calculates a target torque difference ΔT _r * between the left drive wheel 61 and the right drive wheel 62 from the target yaw moment M _r *. In other words, the ECU calculates 5 a torque distribution for the first rotor 22 and the second rotor 23 ,

The ECU 5 calculates a total target torque ΣT _r * for the left drive wheel 61 and the right drive wheel 62 due to an accelerator pedal input K _a and a brake pedal input K _b . For example, if the accelerator pedal input K _{a is} greater than 0 (zero), ie, K _a > 0, and the brake pedal input K _b is 0, ie, K _b = 0, the total target torque ΣT _r * in the drive direction (ie, in FIG the same direction as the direction of rotation), and the total target torque ΣT _r * is increased with an increase in accelerator pedal input K _a .

The ECU 5 calculates a target torque T ₁ * for the first drive gear 61 and a target torque T ₂ * for the second drive gear 62 based on the target torque difference ΔT _r * and the total target torque ΣT _r *.

According to the principle of the three-phase induction machine, the rotor rotates at a speed that is always lower than the speed of the stator rotating field, which is called synchronous speed. The relative speed between the stator field and the rotor exerts a torque. The difference between the synchronous speed (n _s ) and the actual speed (n _x ) of the rotor is called "slip (s)". $$\text{s}=\left({\text{n}}_{\text{s}}-{\text{n}}_{\text{x}}\right)/{\text{n}}_{\text{s}}$$

The relationship between torque and slip in the induction machine 2 is replaced by an in 6 represented expressed torque / slip characteristic. In 6 n _{s is} the synchronous speed; n _{1 is} the actual speed of the first rotor 22 which may be coupled to the left drive wheel 61; n _{2 is} the actual speed of the second rotor 23 which may be coupled to the right drive wheel 62, N _{s is} the slip between the synchronous speed n _s and the speed (ie, the synchronous speed n _s ) of the stator rotating field; N _{1 is} the slip between the synchronous speed n _s and the actual speed n _{1 of} the first rotor 22 ; and N _{2 is} the slip between the synchronous speed n _s and the actual speed n _{2 of} the second rotor 23 ,

From this torque / slip characteristic, it is clear that the left drive wheel 61 generates a torque T ₁ when the slip of the first rotor 22 N ₁ , and the right drive wheel 62 generates a torque T ₂ when the slip of the second rotor is N ₂ .

The ECU 5 determines a frequency of the fundamental magnetic stator rotating field and current commands or command values based on a target torque T ₁ * for the left driving wheel 61, a target torque T ₂ * for the right driving wheel 62, the actual rotational speed n _{1 of} the first rotor 22 , the actual speed n _{2 of} the second rotor 23 , and a selected torque / slip map. Based on the determined frequency and the specific current commands, the ECU controls 5 the inverter 3 for driving the motor 2 ,

The ECU 5 controls the engine 2 for example, as in the control block diagram of 7 , For this reason, the ECU includes 5 a torque / slip map selection module 51; an automatic speed controller (ASR) 52; an integral module 53; a cosθ ₁ - & - sinθ ₁ calculation module 54; a current command calculation module 55 and a current control module 56.

The ECU 5 selects that of the two rotors, which is driven in an unstable operating range, for example, an outer rotor during cornering and uses the speed of the selected rotor as the actual speed of the rotor to be controlled of the motor 2 , Since the outer rotor rotates at a speed greater than the speed of the inner rotor, a controllable speed range of the outer rotor is large, so that the yaw moment at the center of gravity G of the motor can be finely changed by finely changing the speed of the outer rotor becomes. In the following description, the rotational speed of the rotor is the rotational speed of the first rotor 22 ,

The torque / slip selection module 51 selects one of the various torque / slip maps including the target torque T ₁ * for the left drive wheel 61, the target torque T ₂ * for the right drive wheel 62, the actual speed n _{1 of} the first rotor 22 , and the actual speed n _{2 of} the second rotor 23 realized. The selected torque / slip map is indicated by the solid line in FIG 8th shown. The 8th represents a transition from an in 6 illustrated state in which the first drive gear 61, the actual torque T ₁ and the second drive 62, the actual torque T ₂ , to which in 8th shown state in which the target torque T ₁ * for the left drive wheel 61 and the target torque T ₂ * for the right drive wheel 62 are achieved, is.

The ROM of the ECU 5 stores a variety of different torque / slip maps obtained by electromagnetic field simulation. The torque / slip selection module 51 selects one of the plurality of torque / slip maps that satisfies the aforementioned conditions. The plurality of torque / slip maps may be determined by trial or substitute schematics.

The torque / slip selection module 51 determines a target synchronous speed, n _s *, of the stator field in the stator 21 due to the selected torque / slip map. The torque / slip selection module 51 calculates a stator magnetization current, i _m *, to form a magnetic field, a synchronous angular velocity, ω _st *, and a target angular velocity, ω ₁ *, for the first rotor 22 due to the target synchronous speed, n _s *.

The ASR 52 calculates a rotor or torque current, i _τ1 , such that a deviation of the current or actual angular velocity, ω ₁ , in the first rotor 22 from the target angular velocity, ω ₁ *, for the first rotor 22 is reduced to zero.

Integral module 53 integrates the synchronous angular velocity, ω _st *, with respect to time to provide synchronous angular motion θ _st . The calculation module 54 calculates an angular movement θ ₁ for the first rotor 22 due to the synchronous angular movement θ _st and cos θ ₁ & sin θ ₁ .

The current command calculation module 55 calculates three-phase AC commands i _a1 *, i _b1 * and i _c1 * (ie currents in the coordinate system at rest) by processing the stator current i _m * and the rotor current i _τ1 *, based on the cos θ ₁ and sin provided by the calculation _module 54 θ ₁ .

The current control module 56 calculates voltage commands v _u *, v _v *, and v _w * for corresponding U, V, and W phases in response to the current commands i _u *, i _v *, and i _w *, the deviations from detected three-phase Actual AC currents from the corresponding current commands i _a1 *, i _b1 *, and i _c1 * provided by the current command calculation module 55. The voltage commands v _u *, v _v *, and v _w * become the drive of a voltage controlled inverter 3 second hand.

The inverter 3 , the voltage-controlled inverter 3 is formed, provides as an output to drive the motor 2 necessary three-phase alternating currents (AC), due to voltage commands, v _u *, v _v *, and v _w *.

Although in the present embodiment, the torque / slip maps are selectively used to determine the synchronous speed n _s , analysis maps of an electromagnetic field determined by the analysis of electromagnetic fields or maps determined by experiments may be used for determination the synchronous speed, n _s , are used.

Although in the present embodiment, the number of slots in the stator 21 is 36, and the number of slots in both the first rotor 22 as well as in the second rotor 23 40, the present disclosure may also be applied to motors having other slot combinations.

Although in the present embodiment, the first rotor 22 and the second rotor 23 when Squirrel cage trained, the present disclosure is applicable to rotors with a winding.

Although a single stator drives two rotors in the present embodiment, the present disclosure may be applied to a single inverter used to drive two motors of the same structure.

As described above, in the present embodiment, the target torque T ₁ * for the left drive wheel 61 and the target torque T ₂ * for the right drive wheel 62 are calculated based on the target torque difference ΔT _r * and the total target torque ΣT _r *. The frequency f ₀ and the current command A ₀ for the fundamental magnetic rotating field in the stator 21 are derived from the selected torque / slip map which includes the target torque T ₁ * for the left drive wheel 61, the target torque T ₂ * for the right drive wheel 62, the speed n ₁ for the first rotor 22 and the speed n ₂ for the second rotor 23 indicates.

This allows the first rotor 22 and the second rotor 23 during the drive of the first rotor 22 and the second rotor 23 that with different speeds with the single stator 21 rotate with a desired torque distribution.

If the engine 2 is used as a drive source for driving a vehicle, the engine 2 As a result, during cornering, both rotors are appropriately driven by merely selecting the drive frequency necessary for torque distribution between the inner wheel and the outer wheel for a smooth cornering.

Further, the drive frequency may be simply adopted by selecting a torque / slip map from among a plurality of torque / slip maps corresponding to the target torque T ₁ * for the left drive wheel 61 and the target torque T ₂ * for the right drive wheel 62 corresponds, and the frequency fo and the current command A ₀ for the fundamental magnetic rotating field in the stator 21 derived from the selected map.

Further, the speed control is performed by using, as the rotational speeds, the rotational speed of the rotor on the outer wheel side, the torque of which is low and becomes unstable.

This improves the stability of the vehicle during cornering, as compared to when the speed control is performed due to the rotational speed of the rotor on the Innenradseite.

Further, the first rotor 22 and the second rotor 23 arranged such that the stator 21 between them but at a distance from the corresponding axial end faces of the stator 21 ,

Thereby, an electric induction machine with a differential function is performed cost-effectively without increasing the number of components, since it is not necessary to provide a differential gear and a stator and an inverter for each of the two rotors. This leads to a reduction in the weight of the vehicle and a reduction in the manufacturing cost of the engine 2 and the inverter 3 ,

Although the disclosure is directed to, but not limited to, the present embodiment, it will be obvious that those skilled in the art could make changes without departing from the spirit of the present invention. All possible modifications and equivalents are to be considered covered by the appended claims.

LIST OF REFERENCE NUMBERS

1

vehicle

2

Motor (or induction machine)

3

inverter

5

Electronic control unit (ECU) (or control unit)

21

stator

22

First rotor

23

Second rotor

76

Wheel speed sensor for the left drive wheel

77

Wheel speed sensor for the right drive wheel

211

stator core

212

armature coil

213

stator teeth

221

rotor core

222

conductor rail

223

rotor teeth

231

rotor core

232

conductor rail

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2827502 B2 [0002, 0006, 0007]

Claims (4)

A control system for an induction machine comprising two rotors capable of rotating at different speeds, the control system comprising: a control unit, wherein the control unit calculates target torques for the two respective rotors based on a torque distribution between the two rotors and a total torque to be generated by the induction machine; and the control unit selects a common drive frequency of the two rotors as a frequency of the synchronous speed of the induction machine, based on the target torques and the speeds of the corresponding two rotors. Control system after Claim 1 wherein the selection of the drive frequency comprises: selecting a map among a plurality of maps respectively representing the relationship between the torque and the rotational speed of the two rotors corresponding to the target torques of the respective two rotors and the rotational speeds of the respective rotors; and the derivative of the drive frequency from the selected map. An electric vehicle comprising an induction machine comprising two rotors capable of rotating at different speeds, and a control system for the induction machine according to any one of Claims 1 or 2 wherein the two rotors are used as respective drive sources of the left and right drive wheels; the torque distribution between the two rotors is a torque distribution requested during cornering; the total torque is a torque requested by the electric vehicle; and the control unit performs control of the induction machine based on the rotational speed of an outer one of the left and right drive wheels during cornering. Electric vehicle after Claim 3 wherein the induction machine is an axial gap induction machine in which the two rotors face the respective axial end surfaces of the stator. the stator lies between the two rotors.

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