CONTROLLER

Abstract

Controller for controlling a rotating electrical machine (20) which has several winding wire groups (21, 22), wherein the controller has: - an instruction processing unit (55) that calculates an instruction value with respect to the control of the rotating electrical machine; - a temperature calculation unit (81, 82) that calculates a system temperature for each of several systems, each of the several systems having a one-to-one combination of a winding wire group and an inverter (31, 32); - a distributor (60) which, for each of the winding wire groups, calculates a distributed command value by distributing the command value calculated by the command processing unit in accordance with the system temperature; and - a current control section (70, 75) that controls an electric current flowing in each of the winding wire groups on the basis of the distributed command value.

Description

[0001] The present invention generally relates to a controller for controlling a rotating electrical machine.

[0002] An electric power steering device having a motor as its drive power source is known. For example, JP 2013-153619 A discloses an electric power steering device having a first inverter for applying a voltage to a first winding wire and a second inverter for applying a voltage to a second winding wire, wherein a voltage applied to the second winding wire is controlled based on a deviation of the electric currents (i.e., a difference between a current applied to the first winding wire and a current applied to the second winding wire).

[0003] In such a case, if two or more than two systems of winding wires and / or inverters are present, the heat generation state may vary from system to system, which may result in overheating of one system. However, JP 2013-153619 A is silent regarding uneven heat generation among multiple systems.

[0004] US Pat. No. 8,766,577 B2 also discloses a control device for a three-phase rotating machine, in which a first inverter and a second inverter supply two coil sets forming a three-phase motor with alternating voltages having the same amplitude but 30° out of phase. Current detectors detect the phase currents supplied by the inverters to the coil sets. Temperature estimation sections estimate the temperatures of the inverters or the coil sets based on an integration value of the phase current detection values. A current command value limiting section limits the upper limits of the current command values ​​of the two coil sets based on the estimated temperatures.

[0005] DE 10 2011 051 234 A1 teaches a motor control device and a motor control method for controlling an electric motor via multiple inverters and coil sets, as well as an electric power steering system that utilizes the motor control device and the motor control method. EP 0 588 628 B1 relates to a control system for an electric vehicle.

[0006] It is an object of the present invention to provide a controller of a rotating electrical machine that prevents overheating.

[0007] The problem is solved by a controller for controlling a rotating electrical machine having the features of the main claim. Advantageous further developments are the subject of the subclaims.

[0008] According to one aspect of the present invention, the controller for controlling a rotating electric machine having a plurality of winding wire groups includes a command calculation unit, a temperature calculation unit, a distributor, and a current control section.

[0009] The command processing unit calculates a command value for controlling the rotating electrical machine.

[0010] A system comprises a combination of a winding wire group and an inverter corresponding to the system. The temperature calculation unit calculates a system temperature for each of the systems.

[0011] The distributor calculates, for each of the winding wire groups, a distributed command value by distributing the command value calculated by the command calculation unit in accordance with the system temperature.

[0012] The current control section controls an electric current flowing in each of the winding wire groups based on the distributed command value.

[0013] According to the present embodiment, the command value is distributed in accordance with the system temperature to calculate the distributed command value for each of the winding wire systems, so as to prevent or mitigate overheating of the rotating electrical machine and the inverter.

[0014] The objects, features, and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings: Fig. 1 is a block diagram of a controller according to a first embodiment of the present invention; Fig. 2 is a circuit diagram of a motor and an inverter according to the first embodiment of the present invention; Fig. 3 is a block diagram of a current control section according to the first embodiment of the present invention; Fig. 4 is a flowchart of a distribution process according to the first embodiment of the present invention; Fig. 5 is a block diagram of the controller according to a second embodiment of the present invention; Fig. 6 is a flowchart of the distribution process according to the second embodiment of the present invention; Fig. 7 is a flowchart of the distribution process according to the second embodiment of the present invention; and Fig. 8 is a block diagram of the current control section according to a fourth embodiment of the present invention.

[0015] The control device or controller of the present invention will be described below with reference to the drawings. In the following embodiments, like parts are designated by like reference numerals and will not be described repeatedly to avoid redundancy. (First embodiment)

[0016] The controller of the first embodiment of the present invention is described with reference to Fig. 1 to 4 described.

[0017] A controller 51 of the present embodiment controls the driving of a motor 20 (ie, a rotating electric machine) used in an electric power steering system 1 as shown in the Fig. 1 is shown.

[0018] The electric power steering system 1 includes a steering wheel 10 as a steering element, an input shaft 11, a column shaft 12, an intermediate shaft 13, a torsion bar 14, the motor 20, a gear 25, a steering device 15, a current sensor 41, a torque sensor 42, a motor rotation angle sensor 43 (hereinafter also simply referred to as a “rotation angle sensor”) and the like.

[0019] The driver-controlled steering wheel 10 is connected to one end of the input shaft 11. The input shaft 11 is connected to the column shaft 12 via the torsion bar 14.

[0020] The column shaft 12 is connected to an opposite end of the input shaft 11 (i.e., an end opposite to the end of the input shaft 11 connected to the steering wheel 10) via the torsion bar 14. The motor 20 is connected to the column shaft 12 via the transmission 25. The torque output from the motor 20 is transmitted to the column shaft 12 as an auxiliary torque via the transmission 25, which torque assists rotation of the column shaft 12. That is, the electric power steering system 1 of the present embodiment is of the column-assist type in which the rotation of the column shaft 12 is assisted by the auxiliary torque of the motor 20. However, not only the column-assist type but also a rack-assist type of the electric power steering system is applicable to the present invention.

[0021] The intermediate shaft 13 connects the column shaft 12 and the steering device 15 and transmits the rotation of the column shaft 12 to the steering device 15.

[0022] The steering device 15 is constructed of a rack and pinion mechanism with a rack and pinion gear (not shown) and converts rotation of the column shaft 12, which is transmitted to the steering device 15 via the intermediate shaft 13, into reciprocal sliding movement of the rack. A tie rod 16 is provided at both ends of the rack. The tie rod 16 moves reciprocally right and left with the rack (i.e., pulls and pushes a tie rod lever 17 provided at a position between the tie rod 16 and a wheel 19). This steers the wheel 19 contacting a road surface rd.

[0023] The engine 20 is, as in Fig. 2, a three-phase motor comprises a rotor and a stator (not shown). The stator has two systems of winding wires wound on the stator (i.e., a winding wire group 21 of the first system and a winding wire group 22 of the second system are wound on the stator).

[0024] The winding wire group 21 of the first system comprises a U1 coil 211, a V1 coil 212, and a W1 coil 213. The winding wire group 22 of the second system comprises a U2 coil 221, a V2 coil 222, and a W2 coil 223.

[0025] A first inverter 31 has six switching elements 311 to 316 and switches the power supply to the winding wire group 21 of the first system.

[0026] The drain of each of the high-potential-side switching elements 311, 312, and 313, which are the switching elements provided on the high-potential side, is connected to a positive electrode of a battery 35 via a high-potential-side bus line 318. The source of each of the high-potential-side switching elements 311, 312, and 313 is connected to the drain of the low-potential-side switching elements 314, 315, and 316, which are the switching elements provided on the low-potential side.

[0027] The source of each of the low-potential-side switching elements 314, 315, and 316 is grounded via a low-potential-side bus line 319. The nodes between a pair of switching elements (i.e., the nodes of three pairs of the high-potential-side switching elements 311, 312, and 313 and the low-potential-side switching elements 314, 315, and 316) are each connected to one end of the U1 coil 211, one end of the V1 coil 212, and one end of the W1 coil 213.

[0028] A second inverter 32 has six switching elements 321 to 326 and switches the power supply to the winding wire group 22 of the second system.

[0029] The drain of each of the high-potential-side switching elements 321, 322, and 323, which are the switching elements provided on the high-potential side, is connected to the positive electrode of a battery 35 via a high-potential-side bus line 328. The source of each of the high-potential-side switching elements 321, 322, and 323 is connected to the drain of the low-potential-side switching elements 324, 325, and 326, which are the switching elements provided on the low-potential side.

[0030] The source of each of the low-potential-side switching elements 324, 325, and 326 is grounded via a low-potential-side bus line 329. The nodes between a pair of switching elements (i.e., the nodes of three pairs of the high-potential-side switching elements 321, 322, and 323 and the low-potential-side switching elements 324, 325, and 326) are each connected to one end of the U2 coil 221, one end of the V2 coil 222, and one end of the W2 coil 223.

[0031] A relay 33 is provided on the high-potential side of the bus line 318. The relay 33 is composed of a power relay 331 and a reverse-bias protection relay 332. The power relay 331 conducts or interrupts the electric current between the first inverter 31 and the battery 35. The reverse-bias protection relay 332 is provided at a position between the first inverter 31 and the power relay 331.

[0032] A relay 34 is provided on the high-potential side of the bus line 328. The relay 34 is composed of a power relay 341 and a reverse-bias protection relay 342. The power relay 341 conducts or interrupts the electric current between the second inverter 32 and the battery 35. The reverse-bias protection relay 342 is provided at a position between the second inverter 32 and the power relay 341.

[0033] Although the switching elements 311-316, 321-326 and the relays 331, 332, 341 and 342 are all implemented as a metal oxide semiconductor field effect transistor (MOSFET), other types of elements such as an insulated gate bipolar transistor (IGBT) and the like are also usable.

[0034] The reverse-bias protection relays 332 and 342 are connected in the reverse direction with respect to the connection direction of the respective power relays 331 and 341. Such a configuration provides protection for the electronic components such as the first inverter 31, the second inverter 32, and the like by preventing reverse electrical current from flowing to these inverters 31, 32, and the like when, for example, the battery 35 is connected in reverse to the circuit.

[0035] A capacitor 36 and a choke coil 37 are provided at a position between (i) the first inverter 31 and the second inverter 32 and (ii) the battery 35. The capacitor 36 and the choke coil 37 serve as a filter circuit that reduces noise transmitted to and from other devices using the same battery 35 (i.e., devices such as the motor 20, the inverters 31 and 32, and the like).

[0036] The current sensor 41 detects, as in Fig. 1, the electric current fed into each phase of the two winding wire groups (i.e., a U1 current Iu1, a V1 current Iv1, and a W1 current Iw1 fed into the phases of the winding wire group 21 of the first system; and a U2 current Iu2, a V2 current Iv2, and a W2 current Iw2 fed into the phases of the winding wire group 22 of the second system).

[0037] Hereinafter, the U1 current lu1, the V1 current Iv1, the W1 current Iw1; and the U2 current Iu2, the V2 current Iv2 and the W2 current Iw2 are also referred to as phase currents lu1, Iv1, Iw1; and Iu2, Iv2, Iw2.

[0038] The torque sensor 42 detects a torsional moment based on a torsional angle of the torsion bar 14. According to the present embodiment, the torsional moment detected by the torque sensor 42 is referred to as a “steering torque Ts.”

[0039] The rotation angle sensor 43 detects a motor rotation angle θm, which describes the rotation angle of the motor 20. According to the present embodiment, the motor rotation angle θm is considered a mechanical angle.

[0040] Detection signals regarding the phase currents Iu1, Iv1, Iw1, Iu2, Iv2 and Iw2 detected by the current sensor 41, a detection signal regarding the steering torque Ts detected by the torque sensor 42 and a detection signal regarding the motor rotation angle θm detected by the rotation angle sensor 43 are given to the controller 51.

[0041] The controller 51 manages, as described in the Fig. 1 and Fig. 2, a controller of the motor 20 and is provided as a microprocessor or the like to perform various operations and calculations using a central processing unit (CPU), a ROM, a RAM, an input / output (I / O) and the bus line connecting these elements and the like in the microprocessor.

[0042] Each of many processes in the controller 51 may be a software process based on execution of a pre-stored program by the CPU or a hardware process based on an electronic circuit dedicated to such a process.

[0043] The controller 51 generates a control signal that controls the switching on and off of the switching elements 311-316, 321-326 based on the detection values ​​and the like from the current sensor 41, the torque sensor 42, the rotation angle sensor 43, and the like. The generated control signal is applied to the gate of the switching elements 311-316, 321-326 via a drive circuit (i.e., a pre-stage circuit) 49.

[0044] Furthermore, the controller 51 controls an ON-OFF operation of the relays 331, 332, 341 and 342. In the Fig. 2, to improve the readability of the drawing, control lines connected to the relays 331, 332, 341 and 342 are omitted from the drawing. Furthermore, the control circuit 49 is shown in the Fig. 1, Fig. 3 and other figures not shown.

[0045] According to the present embodiment, the first system winding wire group 21, the first inverter 31 and the relay 33 serve as a “first system 101”, and the second system winding wire group 22, the second inverter 32 and the relay 34 serve as a “second system 102”.

[0046] The controller 51 has, as shown in the Fig. 1 and Fig. 3, a motor angular velocity calculation unit 44, a steering angular velocity calculation unit 45, a command calculation unit 55, a distributor 60, an electric current control section 70 (hereinafter referred to as current control section 70), a first-system temperature calculation unit 81, a second-system temperature calculation unit 82, and the like.

[0047] The motor angular velocity calculation unit 44 calculates a motor angular velocity ωm based on a motor rotation angle θm.

[0048] The steering angular velocity calculation unit 45 converts the motor angular velocity ωm into a steering angular velocity ωs based on the gear ratio of the transmission 25 and the like.

[0049] The instruction arithmetic unit 55 has a basic instruction arithmetic unit 56, a correction instruction arithmetic unit 57 and an adder 58.

[0050] The basic command calculation unit 56 and the correction command calculation unit 57 perform calculation using, for example, at least a part of a vehicle speed, a steering wheel angle and the motor rotation angle θm, the motor angular velocity ωm, the steering angular velocity ωs together with other parameters.

[0051] The basic command calculation unit 56 calculates a basic assist command value B0 in accordance with the steering torque Ts.

[0052] The correction command calculation unit 57 calculates a correction command value C0 for correcting the basic assist command value B0. The correction command value C0 can be, for example, a value for a control for improving convergence of the steering operation, a control related to vehicle movement, and the like. In the present embodiment, the correction command calculation unit 57 is described as a functional block. However, such a configuration can be changed, for example, to calculate a correction command value for each of these controls.

[0053] The adder 58 adds the basic assist command value B0 and the correction command value C0 to calculate an assist command value AT.

[0054] The distributor 60 distributes the assist command value AT based on a first-system temperature T1 calculated by the first-system temperature calculation unit 81 and a second-system temperature T2 calculated by the second-system temperature calculation unit 82, and calculates a first-system torque command value trq1* and a second-system torque command value trq2*. The first-system torque command value trq1* and the second-system torque command value trq2* will be described in more detail below. In the present embodiment, the assist command value AT corresponds to a "command value," and the first-system torque command value trq1* and the second-system torque command value trq2* each correspond to a "distributed command value."

[0055] The current control section 70 has a first-system current control section 71 and a second-system current control section 72 and controls the electric current flowing to the winding wire groups 21 and 22.

[0056] The current control section 71 of the first system has, as shown in Fig. 3, a current command calculation unit 710, a d / q (direct / quadrature) converter 711, a subtractor 712, a PI calculation unit 713, and a PWM (pulse width modulation) calculation unit 714, and generates a control signal relating to controlling the electric current flowing to the winding wire group 21 of the first system.

[0057] The current command calculation unit 710 calculates a d-axis current command value Id1* and a q-axis current command value Iq1* of the first system 101 by performing a mapping calculation and the like based on the first system torque command value trq1*.

[0058] The d / q converter 711 performs a d / q conversion of the phase currents Iu1, Iv1 and Iw1, which are detected by the current sensor 41 (see Fig. 1, the current sensor 41 is in the Fig. 3 not shown), and calculates a d-axis current detection value Id1 and a q-axis current detection value Iq1 of the first system 101.

[0059] The subtractor 712 calculates a d-axis current deviation ΔId1, which is a deviation of the d-axis current command value Id1* from the d-axis current detection value Id1 due to feedback, and calculates a q-axis current deviation ΔIq1, which is a deviation of the q-axis current command value Iq1* from the q-axis current detection value Iq1 due to feedback.

[0060] The PI calculation unit 713 calculates voltage command values ​​Vd1* and Vq1* by performing PI calculation and the like so that the electric current deviations ΔId1 and ΔIq1 each converge to zero. The calculated voltage command values ​​Vd1* and Vq1* are converted into voltage command values ​​Vu1*, Vv1*, and Vw1* of three phases.

[0061] The PWM arithmetic unit 714 compares the voltage command values ​​Vu1*, Vv1*, and Vw1* in three phases with a carrier wave and generates a control signal that controls the switching on and off of the switching elements 311 to 316. The generated control signal is supplied to the first inverter 31 (first system inverter 31) via the drive circuit 49 (see Fig. 2). In this way, the power supply of the winding wire group 21 of the first system is controlled.

[0062] The second system current control section 72 includes a current command calculation unit 720, a d / q converter 721, a subtractor 722, a PI calculation unit 723, and a PWM calculation unit 724, and generates a control signal related to controlling the electric current flowing to the second system winding wire group 22.

[0063] The current command calculation unit 720 calculates a d-axis current command value Id2* and a q-axis current command value Iq2* of the second system 102 by performing a map calculation and the like based on the second system torque command value trq2*.

[0064] The d / q converter 721 performs d / q conversion of the phase currents Iu2, Iv2, and Iw2 detected by the current sensor 41, and calculates a d-axis current detection value Id2 and a q-axis current detection value Iq2 of the second system 102.

[0065] The subtractor 722 calculates a d-axis current deviation ΔId2, which is a deviation of the d-axis current command value Id2* from the d-axis current detection value Id2 due to feedback, and calculates a q-axis current deviation ΔIq2, which is a deviation of the q-axis current command value Iq2* from the q-axis current detection value Iq2 due to feedback.

[0066] The PI calculation unit 723 calculates voltage command values ​​Vd2* and Vq2* by performing PI calculation and the like so that the electric current deviations ΔId2 and ΔIq2 each converge to zero. The calculated voltage command values ​​Vd2* and Vq2* are converted into voltage command values ​​Vu2*, Vv2*, and Vw2* of three phases.

[0067] The PWM arithmetic unit 724 compares the voltage command values ​​Vu2*, Vv2*, and Vw2* in three phases with a carrier wave and generates a control signal that controls the switching on and off of the switching elements 321 to 326. The generated control signal is supplied to the second inverter 32 (second system inverter 32) via the drive circuit 49 (see Fig. 2). In this way, the power supply of the winding wire group 22 of the second system is controlled.

[0068] The response sensitivity of the current control section 71 of the first system and the response sensitivity of the current control section 72 of the second system can be the same or different from each other. More specifically, the control parameter that determines the frequency response can have the same value in both the current control section 71 of the first system and the current control section 72 of the second system, or it can have different values ​​in both sections 71 and 72.

[0069] If the responsiveness of the electric current control in the two sections 71, 72 is different, the current control section 71 of the first system may, for example, have a low-range responsiveness (ie, a low-frequency or low-sensitivity responsiveness) corresponding to a minimum degree of responsiveness to the electric current according to which the command value is just realizable, and the current control section 72 of the second system may, for example, have an high-range responsiveness achieving a higher degree of responsiveness to the electric current (ie, a high-frequency or high-sensitivity responsiveness).By setting one of the first-system current control section 71 and the second-system current control section 72 to have a low-range response and setting the other to have an high-range response, vibration and / or noise are reduced compared to the case where both sections are set to have an high-range response.

[0070] Furthermore, in the current control section 71 of the first system and in the current control section 72 of the second system, non-interference control can be carried out, which reduces interference between the two systems.

[0071] Below we refer again to the Fig. 1. The first system temperature calculation unit 81 calculates the first system temperature T1, which is the temperature of the first system 101.

[0072] The temperature T1 of the first system can be, for example, the temperature of the switching elements 311 to 316 of the first inverter 31, the temperature of the winding group 21 of the first system, or the temperature of a motor line connecting the winding group 21 of the first system and the first inverter 31.

[0073] The temperature T1 of the first system can be calculated based on a detection value of a temperature sensor (not shown) or estimated based on the phase currents Iu1, Iv1 and Iw1.

[0074] The second system temperature calculation unit 82 calculates the second system temperature T2, which is the temperature of the second system 102.

[0075] The temperature T2 of the second system may be, for example, the temperature of the switching elements 321 to 326 of the second inverter 32, the temperature of the winding group 22 of the second system, or the temperature of a motor line connecting the winding group 22 of the second system and the second inverter 32.

[0076] The temperature T2 of the second system can be calculated based on a detection value of a temperature sensor (not shown) or estimated based on the phase currents Iu2, Iv2 and Iw2.

[0077] The phase currents Iu1, Iv1, Iw1, Iu2, Iv2 and Iw2 used to estimate the system temperature can be sensed values ​​or command values.

[0078] Furthermore, the temperature calculation units 81 and 82 in the Fig. 1 is displayed as calculating the temperature of inverters 31 and 32. The same can be done for the Fig. 5, which is described below.

[0079] Furthermore, in the first system 101, when the temperature is sensed or estimated from two or more positions (such as each of the switching elements 311 to 316), the temperature T1 of the first system may be the highest temperature sensed or estimated. Furthermore, instead of using the highest temperature sensed or estimated, the average temperature may be used. The same may apply to the temperature T2 of the second system.

[0080] The temperature T1 of the first system and the temperature T2 of the second system are output to the distributor 60.

[0081] Herein, a heat value Q is described by the following equation (1), in which R describes the resistance value and I describes the electric current. Q=R×I2

[0082] Since the heat value Q is proportional to the square of the electric current I, in order to reduce the heat value Q, it is important to reduce the electric current I, as shown in equation (1).

[0083] According to the present embodiment, in order to prevent the uneven heat generation among the two systems and overheating of one system, the assist command value AT is distributed in accordance with the temperature T1 of the first system and the temperature T2 of the second system.

[0084] The distribution process of the present embodiment is described below with reference to the Fig. The flowchart shown in Figure 4 is described. The distribution process is carried out at predetermined intervals by the distributor 60.

[0085] In step S101 (hereinafter, a "step" is replaced by reference symbol "S"), it is determined whether an error has occurred in either system. If it is determined that no error has occurred (S101=NO), the process proceeds to S108. If it is determined that an error has occurred (S101=YES), the process proceeds to S102.

[0086] In S102, an assistance command value AT is obtained or obtained.

[0087] In S103, it is determined whether the assistance command value AT is greater than one-half of the rated torque of motor 20. If it is determined that the assistance command value AT is less than or equal to 1 / 2 of the rated torque (S103=NO), the process proceeds to S105. If it is determined that the assistance command value AT is greater than one-half of the rated torque (S103=YES), the process proceeds to S104.

[0088] In S104, since the first system 101 or the second system 102 having a fault cannot be used, the assist command value AT is limited to one half of the rated torque.

[0089] In S105, it is determined whether or not the faulty system is the first system 101. In the flowchart, the first system 101 is designated as "1st System." If it is determined that the faulty system is the first system 101 (S105=YES), the process proceeds to S106. If it is determined that the faulty system is not the first system 101 (i.e., if the faulty system is the second system 102) (S105=NO), the process proceeds to S107.

[0090] In S106, the torque command value trq1* of the first system and the torque command value trq2* of the second system are calculated. In this case, the torque command value trq1* of the first system is set to zero with an error, and the torque command value trq2* of the second system is set to the assist command value AT. That is, the torque command value trq1* of the first system and the torque command value trq2* of the second system are described by the following equations (2-1) and (2-2). trq1*=0 trq2*=AT

[0091] In S107, the torque command value trq1* of the first system and the torque command value trq2* of the second system are calculated. Here, the torque command value trq2* of the second system is set to zero with an error, and the torque command value trq1* of the first system is set to the assist command value AT. That is, the torque command value trq1* of the first system and the torque command value trq2* of the second system are described by the following equations (3-1) and (3-2). trq1*=AT trq2*=0

[0092] In S108, following a determination that no error has occurred (S101=NO), the assistance command value AT is obtained as in S102.

[0093] In S109, the temperature T1 of the first system and the temperature T2 of the second system are obtained.

[0094] In S110 it is determined whether the system imbalance is permissible.

[0095] If it is determined that the system imbalance is not permissible (S110=NO), the process proceeds to S113. If it is determined that the system imbalance is permissible (S110=YES), the process proceeds to S111.

[0096] In S111, the distribution coefficients K1 and K2 for the two systems are calculated. The distribution coefficient K1 for the first system 101 and the distribution coefficient K2 for the second system 102 are described by the following equations (4-1) and (4-2). Furthermore, the distribution coefficients K1 and K2 can also be calculated using equations other than equations (4-1) and (4-2) or using a map or the like. K1=T2 / (T1+T2) K2=T1 / (T1+T2)

[0097] In S112, the torque command value trq1* of the first system and the torque command value trq2* of the second system are calculated. The torque command value trq1* of the first system and the torque command value trq2* of the second system are described by the following equations (5-1) and (5-2). trq1*=AT×K1 trq2*=AT×K2

[0098] In S113, following a determination that system imbalance is not allowed (S110=NO), the assist command value AT is evenly distributed between the two systems, and the torque command value trq1* of the first system and the torque command value trq2* of the second system are calculated. Here, both the torque command value trq1* of the first system and the torque command value trq2* of the second system are set to half of the assist command value AT. That is, the torque command value trq1* of the first system and the torque command value trq2* of the second system are described by the following equations (6-1) and (6-2). trq1*=AT / 2 trq2*=AT / 2

[0099] When the temperature T1 of the first system is 60 [°C] and the temperature T2 of the second system is 40 [°C], according to equations (4-1) and (4-2), the distribution coefficient K1 is 0.4 and the distribution coefficient K2 is 0.6. Further, according to equations (5-1) and (5-2), the torque command value trq1* of the first system with respect to the first system 101 having a relatively high temperature is smaller than the torque command value trq2* of the second system having a relatively low temperature. That is, when T1 > T2, the coefficients are determined as K1 < K2, so that the torques trq1* < trq2* are equal. In this way, the supply of electric power to the first system 101 is reduced.

[0100] According to the present embodiment, since the torque command values ​​trq1* and trq2* are calculated such that a supply amount of electric power to the high-temperature system is reduced in accordance with the torque command values ​​trq1* and trq2*, overheating of the motor 20 and the inverters 31, 32 is prevented.

[0101] The controller 51 controls the motor 20 having a plurality of winding groups 21 and 22, as described in more detail above, and is equipped with the command computing unit 55, the temperature computing units 81 and 82, the distributor 60, and the current control section 70.

[0102] The command calculation unit 55 calculates the assistance command value AT with respect to the control of the motor 20.

[0103] The systems 101, 102 are defined as a combination of the winding wire group 21 and the inverter 31 and a combination of the winding wire group 22 and the inverter 32, respectively.

[0104] The temperature calculation units 81 and 82 calculate the system temperatures T1 and T2 of the systems 101, 102, respectively.

[0105] The distributor 60 distributes the assist command value AT to each of the winding wire groups 21 and 22 in accordance with the system temperatures T1 and T2 and calculates the torque command values ​​trq1* and trq2* for the respective winding wire groups 21 and 22.

[0106] The current control section 70 controls the electric current flowing to the winding wire groups 21 and 22 based on the torque command values ​​trq1* and trq2*.

[0107] According to the present embodiment, since the assist command value AT is distributed in accordance with the system temperatures T1 and T2 and the torque command values ​​trq1* and trq2* are calculated based on the distributed command values, overheating of the motor 20 and the inverters 31 and 32 is prevented.

[0108] The system temperatures T1 and T2 describe the highest temperature or the average temperature at the multiple positions of the winding wire groups 21, 22 and the inverters 31, 32. Therefore, based on the system temperatures T1 and T2, the assist command value AT is appropriately distributed to control the torque command value of a high-temperature system to a low value. (Second embodiment)

[0109] The second embodiment of the present invention is shown in the Fig. 5 and Fig. 6 shown.

[0110] A controller 52 of the present embodiment has, as shown in Fig. 5, an overheat protection section 83.

[0111] When the first system temperature T1 is above an overheat determination threshold value Tth, the overheat protection section 83 determines that an overheat protection required state exists, and the overheat protection section 83 limits the assist command value AT to an overheat protection limiting value AE.

[0112] When the second system temperature T2 is above the overheat determination threshold value Tth, the overheat protection section 83 determines that an overheat protection required state exists, and the overheat protection section 83 limits the assist command value AT to the overheat protection limit value AE.

[0113] In the present embodiment, the overheat determination threshold Tth is the same for both the first system temperature T1 and the second system temperature T2. However, the threshold Tth for the two systems may have different values.

[0114] The distribution process of the present embodiment is described with reference to the Fig. 6. In the present embodiment, the process from S208 to S213 is a process executed by the overheat protection section 83, and the remaining processes are processes executed by the distributor 60. Furthermore, the process from S209 may also be executed by the distributor 60.

[0115] In addition, it can be arbitrarily determined whether the process from S208 to S213 is executed by the distributor or the overheat protection section 83. That is, the distributor 60 can execute an overheat protection process. In such a case, the box (ie, a functional block) of the overheat protection section 83 in the Fig. 5 contained in the box of the distributor 60. The same applies to the third embodiment.

[0116] The process from S201 to S207 is the same as the process from S101 to S207 in the Fig. 4.

[0117] In S208, the overheat protection section 83 obtains the assistance command value AT.

[0118] In S209, the distributor 60 and the overheat protection section 83 receive the first system temperature T1 and the second system temperature T2.

[0119] In S210, it is determined whether the temperature T1 of the first system or the temperature T2 of the second system is above the overheat determination threshold Tth. If it is determined that the temperature T1 of the first system and the temperature T2 of the second system are less than or equal to the overheat determination threshold Tth (S210=NO), it is determined that the systems are not in the overheat protection required state, and the assistance command value AT is output to the distributor 60, after which the process proceeds to S214.

[0120] When it is determined that the first system temperature T1 or the second system temperature T2 is above the overheat determination threshold Tth (S210=YES), it is determined that the system has the overheat protection required state, and the process proceeds to S211.

[0121] In S211, the overheat protection limit value AE is obtained.

[0122] In S212, it is determined whether the assist command value AT is greater than the overheat protection limit value AE. If it is determined that the assist command value AT is less than or equal to the overheat protection limit value AE (S212=NO), the assist command value AT is output to the distributor 60, and the process proceeds to S214. If it is determined that the assist command value AT is greater than the overheat protection limit value AE (S212=YES), the process proceeds to S213.

[0123] In S213, the assistance command value AT is limited to the overheat protection limit value AE and output to the distributor 60.

[0124] The process from S214 to S217 is the same as the process from S110 to S114 in the Fig. 4.

[0125] According to the present embodiment, the controller 52 includes the overheat protection section 83. The overheat protection section 83 limits the assist command value AT (S213) when it is determined that the system temperature T1 or T2 has the overheat protection required state (S210=YES in the Fig. 6). This prevents overheating of the motor 20 and the inverters 31, 32. The same effects as in the embodiment described above are also achieved. (Third embodiment)

[0126] The third embodiment of the present invention is shown in Fig. 7 shown.

[0127] Since the distribution process of the present embodiment is different from the second embodiment, the following description of the present embodiment is directed to this difference.

[0128] Below is the flowchart of the distribution process with reference to the Fig. 7. In the present embodiment, the process from S308 to S313 is a process executed in the overheat protection section 83, and the process other than S310 to S313 is a process executed by the distributor 60.

[0129] The process from S301 to S313 is essentially the same as that from S201 to S213 in the Fig. 6.

[0130] In S314 following S312 or S313, the assist command value AT is distributed at a predetermined ratio, and the first system torque command value trq1* and the second system torque command value trq2* are calculated.

[0131] Here, the assist command value AT is evenly distributed, and both the torque command value trq1* of the first system and the torque command value trq2* of the second system are set to half of the assist command value AT. That is, the torque command value trq1* of the first system and the torque command value trq2* of the second system are described by the following equations (7-1) and (7-2). trq1*=AT / 2 trq2*=AT / 2

[0132] The process from S315 to S318 is the same as that from S214 to S217 in the Fig. 6.

[0133] According to the present embodiment, as shown in equations (7-1) and (7-2), the first system temperature T1 or the second system temperature T2 is above the overheat determination threshold Tth, which means that when the overheat protection process is performed, the assist command value AT is evenly distributed and the distribution in accordance with the system temperatures T1 and T2 is not performed.

[0134] According to the present embodiment, the distributor 60 stops the distribution of the assistance command value AT in accordance with the system temperatures T1 and T2 (S314) when it is determined that the system temperature T1 or T2 has the overheat protection required state (S310=YES in the Fig. 7). That is, in the present embodiment, when the system temperature T1 or T2 is above the overheat determination threshold Tth and the assist command value AT is restricted, instead of performing temperature-aware command value distribution in accordance with the system temperatures T1 and T2, a predetermined ratio distribution of the assist command value AT is performed.

[0135] This simplifies the calculation of overheating protection.

[0136] Furthermore, the same effects as in the above-described embodiment are also achieved. (Fourth embodiment)

[0137] The fourth embodiment of the present invention is shown in Fig. 8 shown.

[0138] The present embodiment differs from the above-described embodiments in a current control section 75. The distribution process in the distributor 60 and the like may be the same as any of the first to third embodiments. Furthermore, in the present embodiment, it is assumed that the responsiveness of the electric current control in the first system 101 and the responsiveness of the electric current control in the second system 102 are the same.

[0139] The current control section 75 includes the current command arithmetic units 710 and 720, the d / q converters 711 and 721, an adder 751, a subtractor 752, a command adder 753, a command subtractor 754, subtractors 755 and 756, PI arithmetic units 757 and 758, an adder 761, a subtractor 766 and converters 762 and 767, and PWM arithmetic units 763 and 768.

[0140] The adder 751 adds the d-axis current detection value Id1 with respect to the first system 101 on which the d / q conversion has been performed by the d / q converter 711 and the d-axis current detection value Id2 with respect to the second system 102 on which the d / q conversion has been performed by the d / q converter 721, and calculates a d-axis current addition value Id+.

[0141] The adder 751 adds the q-axis current detection value Iq1 with respect to the first system 101 on which the d / q conversion has been performed by the d / q converter 711 and the q-axis current detection value Iq2 with respect to the second system 102 on which the d / q conversion has been performed by the d / q converter 721, and calculates a q-axis current addition value Iq+.

[0142] The subtractor 752 subtracts the d-axis current detection value Id2 of the second system 102 from the d-axis current detection value Id1 of the first system 101 and calculates a d-axis current subtraction value Id-.

[0143] The subtractor 752 subtracts the q-axis current detection value Iq2 of the second system 102 from the q-axis current detection value Iq1 of the first system 101 and calculates a q-axis current subtraction value Iq-.

[0144] The command adder 753 adds the d-axis current command value Id1* of the first system 101 and the d-axis current command value Id2* of the second system 102 and calculates a d-axis addition current command value Id+*.

[0145] The command adder 753 adds the q-axis current command value Iq1* of the first system 101 and the q-axis current command value Iq2* of the second system 102 and calculates a q-axis addition current command value Iq+*.

[0146] The command subtractor 754 subtracts the d-axis current command value Id2* of the second system 102 from the d-axis current command value Id1* of the first system 101 and calculates a d-axis subtraction current command value Id-*.

[0147] The command subtractor 754 subtracts the q-axis current command value Id2* of the second system 102 from the q-axis current command value Iq1* of the first system 101 and calculates a q-axis subtraction current command value Iq-*.

[0148] The subtractor 755 calculates a d-axis addition current deviation ΔId+, which is a deviation of the d-axis addition current command value Id+* from the d-axis current addition value Id+.

[0149] The subtractor 755 calculates a q-axis addition current deviation ΔIq+, which is a deviation of the q-axis addition current command value Iq+* from the q-axis current addition value Iq+.

[0150] The subtractor 756 calculates a d-axis subtraction current deviation ΔId-, which is a deviation of the d-axis subtraction current command value Id-* from the d-axis current subtraction value Id-.

[0151] The subtractor 756 calculates a q-axis subtraction current deviation ΔIq-, which is a deviation of the q-axis subtraction current command value Iq-* from the q-axis current subtraction value Iq-.

[0152] The PI calculation unit 757 calculates addition voltage command values ​​Vd+* and Vq+* based on the PI calculation and the like so that the addition current deviations ΔId+ and ΔIq+ each converge to zero.

[0153] The PI calculation unit 758 calculates subtraction voltage command values ​​Vd-* and Vq-* based on the PI calculation and the like so that the subtraction current deviations ΔId- and ΔIq- converge to zero, respectively.

[0154] The adder 761 adds the addition voltage command value Vd+* and the subtraction voltage command value Vd-* around a d-axis to calculate a first-system pre-conversion voltage command value Vd1*_b, and adds the addition voltage command value Vq+* and the subtraction voltage command value Vq-* around a q-axis to calculate a first-system pre-conversion voltage command value Vq1*_b.

[0155] In converter 762, the pre-conversion voltage command values ​​Vd1*_b and Vq1*_b of the first system are multiplied by a scaling factor of 0.5 to calculate the first system voltage command values ​​Vd1* and Vq1*. Furthermore, the calculated voltage command values ​​Vd1* and Vq1* are converted into three-phase voltage command values ​​Vu1*, Vv1*, and Vw1*.

[0156] Same as the PWM arithmetic unit 714 in the Fig. 4, the PWM arithmetic unit 763 compares the voltage command values ​​Vu1*, Vv1* and Vw1* with a carrier wave, and the PWM arithmetic unit 763 generates a control signal that controls the turning on and off of the switching elements 311 to 316.

[0157] The subtractor 766 subtracts the subtraction voltage command value Vd-* from the addition voltage command value Vd+* around the d-axis to calculate the second-system pre-conversion voltage command value Vd2*_b, and subtracts the subtraction voltage command value Vd-* from the addition voltage command value Vd+* around the q-axis to calculate the second-system pre-conversion voltage command value Vq2*_b.

[0158] In converter 767, the pre-conversion second-system voltage command values ​​Vd2*_b and Vq2*_b are multiplied by a scaling factor of 0.5 to calculate the second-system voltage command values ​​Vd2* and Vq2*. Furthermore, the calculated voltage command values ​​Vd2* and Vq2* are converted into the three-phase voltage command values ​​Vu2*, Vv2*, and Vw2*.

[0159] Same as the PWM arithmetic unit 724 in the Fig. 4, the PWM arithmetic unit 768 compares the voltage command values ​​Vu2*, Vv2* and Vw2* with a carrier wave, and the PWM arithmetic unit 768 generates a control signal that controls the turning on and off of the switching elements 321 to 326.

[0160] In the current control section 75, as in the first embodiment, non-interference control can be performed, which reduces interference between the two systems.

[0161] According to the present embodiment, addition and subtraction are performed for appropriate control of the electric current. This reduces the influence of temperature changes and the dispersion of characteristics among individual electronic components and elements, etc.

[0162] Furthermore, the same effects as in the above-described embodiment are also achieved. (Other embodiments)(a) The number of systems

[0163] In the embodiments described above, the number of systems is two.

[0164] In further embodiments, the number of systems may be three or more than three. That is, the number of winding wire groups may be three or more than three, and the inverter may be provided accordingly for each of the winding wire groups. (b) Distributor

[0165] In the embodiments described above, the distribution of the command value is based on the system temperature itself.

[0166] In further embodiments, an operating guarantee temperature or a maximum heat resistance temperature corresponding to the highest temperature threshold at which the system can operate may be predetermined, and the distribution of the command value may be made in accordance with a difference between the operating guarantee temperature and the system temperature. That is, when the difference between the operating guarantee temperature and the system temperature is small in one system, the distribution coefficient for such a system may be controlled to be relatively small compared to the coefficient for the other systems. Furthermore, when the temperature is detected / estimated at multiple locations in each of the systems, the distribution of the command value may preferably be made in accordance with the smallest difference between the operating guarantee temperature and the system temperature of one of the multiple locations.

[0167] Further, in the case where the overheat protection control is performed based on the difference described above, the system temperature is determined to have the overheat protection required state when the difference is below a determination threshold, and a process similar to the second or third embodiment may be performed.

[0168] In this way, the command value can be distributed appropriately to avoid overheating (i.e., to keep the system temperature below the operating warranty temperature). (c) Rotating electrical machine

[0169] The rotating electrical machine can be not only a motor (i.e. an electric motor), but also a generator or a motor generator that serves as both a motor and a generator.

[0170] Furthermore, the rotating electric machine used in an electric power steering system in the above-described embodiment may also be used in another system or device other than the electric power steering system in other embodiments.

Claims

[1] Controller for controlling a rotating electrical machine (20) having a plurality of winding wire groups (21, 22), the controller comprising: - a command calculation unit (55) which calculates a command value relating to a control of the rotating electrical machine; - a temperature calculation unit (81, 82) that calculates a system temperature for each of a plurality of systems, each of the plurality of systems having a one-to-one combination of a winding wire group and an inverter (31, 32); - a distributor (60) which calculates, for each of the winding wire groups, a distributed command value by distributing the command value calculated by the command calculation unit in accordance with the system temperature; and - a current control section (70, 75) that controls an electric current flowing in each of the winding wire groups based on the distributed command value. [2] Controller according to claim 1, characterized by that it further comprises an overheat protection section (83) which limits the command value when it is determined that the system temperature has an overheat protection required condition. [3] Controller according to claim 2, characterized by that the distributor stops distributing the command value in accordance with the system temperature when it is determined that the system temperature has the overheat protection requirement state. [4] Controller according to one of claims 1 to 3, characterized by that the system temperature is either the highest or an average of temperature measurements at several temperature measuring points in one winding wire group and one inverter. [5] Controller according to one of claims 1 to 4, characterized bythat the distributor distributes the command value to each of the winding wire groups in accordance with a difference between an operating guarantee temperature and the system temperature.

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