CONTROL DEVICE FOR ROTARY ELECTRIC MACHINE AND ELECTRIC POWER STEERING DEVICE

Abstract

A control device for a rotating electrical machine for controlling a rotating electrical machine (80) having a plurality of winding sets (810, 820) each having a plurality of coils (811 to 813, 821 to 823) corresponding to a plurality of phases, the control device for a rotating electrical machine comprising: - an inverter (120, 220) arranged for each winding set and converting energy of the rotating electrical machine; - a power source relay (180, 280) arranged for each inverter and interrupting a power supply from a power source (5) to the inverter; - a terminal voltage detector (140, 240, 165, 265) which detects a terminal voltage from each coil; and - a controller (40) comprising an inverter controller (41, 42) for controlling each inverter, a relay controller (43) for controlling each power source relay, and an abnormality determination unit (45) for determining an abnormality of each inverter and each winding set, wherein - a combination of each winding set and a corresponding inverter is defined as a system; - one of the systems in which an abnormality occurs is defined as a faulty system; - another of the systems operating normally is defined as a normal system; - when the rotating electrical machine is controlled using the normal system: - the relay controller controls the power source relay to interrupt the power supply from the power source to the inverter in the faulty system; - the abnormality determination unit determines a short-circuit location based on the terminal voltage in the faulty system; and - the inverter controller corrects a command value relating to the control of the inverter in the normal system in accordance with a specific short-circuit location; - the abnormality determination unit determines the short-circuit location after a predetermined waiting time has elapsed since the interruption of the power supply from the power source to the inverter in the faulty system; - the abnormality determination unit determines the short-circuit location when the rotating electrical machine is in a constant rotation state; and - the short-circuit location includes a short-circuited phase among the plurality of phases, and the short-circuited phase includes a phase in which a power fault abnormality or a ground fault abnormality occurs.

Description

[0001] The present invention relates to a control device for a rotating electric machine and an electric power steering device having the control device.

[0002] A control device for a multiphase rotating machine is known. For example, in JP 4 831 503 B2, a switching element in a fault-free system is controlled to cancel a braking torque generated in a faulty system.

[0003] In JP 4 831 503 B2, a switching element with an ON fault is detected in a state where a control part has stopped PWM (pulse width modulation) control, i.e., in a state where a motor has stopped. However, in JP 4 831 503 B2, it is not possible to detect the switching element with an ON fault in a state where the motor is rotating.

[0004] DE 10 2013 103 016 A1 relates to a motor drive device for driving a motor, which can be used, for example, in an electric power steering system of a vehicle. In the motor drive device according to DE 10 2013 103 016 A1, when a fault detection part detects a fault in an inverter circuit in a first power supply system, a drive control part stops driving the motor through the inverter circuit. An on / off control part turns off a first power supply relay of a power supply on / off part. In a state in which the inverter circuit stops a motor drive operation, a first coil set of the motor generates an induced voltage due to rotation caused by an external force. The induced voltage is fed from the inverter circuit to a first power supply relay and a parasitic diode of the first power supply relay.regenerated into a battery. This is intended to protect circuit elements in the power supply system that fails from destruction.

[0005] DE 10 2011 052 368 A1 discloses an electrical power conversion device that converts electrical power supplied to a rotating electrical machine. DE 10 2011 000 024 A1 relates to a drive control method for a motor drive device, and WO 2015 / 136 976 A1 teaches a control device and a control method for an electric motor.

[0006] It is an object of the present invention to provide a control device for a rotating electric machine that can determine a short-circuit location even when a rotating electric machine has a rotating state, and an electric power steering device having the control device for a rotating electric machine.

[0007] The problem is solved by the subject matter of the independent claims. Advantageous further developments are specified in the dependent claims.

[0008] In the rotary electric machine control device and the electric power steering device according to the present invention, in a state where the power supply from the power source to the inverter is interrupted by the power source relay part in the faulty system, a short-circuit location is determined based on a terminal voltage generated by a counter electromotive force of the rotary electric machine. Therefore, the short-circuit location can be appropriately determined even when the rotary electric machine is in a rotating state. Furthermore, torque ripple can be reduced by correcting a command value in accordance with the short-circuit location.

[0009] 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 schematic diagram of a configuration illustrating a steering system according to a first embodiment of the present invention; Fig. 2A and Fig. 2B are exemplary diagrams illustrating an engine according to the first embodiment of the present invention, wherein Fig. 2A shows a schematic perspective view and Fig. 2B shows an exemplary figure illustrating a phase sequence; Fig. 3 is an explanatory diagram illustrating an electrical angle according to the first embodiment of the present invention; Fig. 4 is a circuit diagram illustrating a motor control device according to the first embodiment of the present invention; Fig. 5 is a block diagram illustrating a control part according to the first embodiment of the present invention; Fig. 6 is a flowchart illustrating abnormality determination processing according to the first embodiment of the present invention; Fig. 7 is a flowchart illustrating short circuit location determination processing according to the first embodiment of the present invention; Fig. 8A to 8F are exemplary diagrams illustrating a q-axis current correction value according to the first embodiment of the present invention; Fig. 9A is an explanatory diagram illustrating an average value of terminal voltages during a one-system drive when a short-circuit abnormality has not occurred according to the first embodiment of the present invention, and Fig. 9B is an explanatory diagram illustrating a terminal voltage of each phase during one-system driving when no short-circuit abnormality has occurred according to the first embodiment of the present invention; Fig. 10A is an explanatory diagram illustrating an average value of terminal voltages during a single-system drive when a W-phase ground fault abnormality has occurred according to the first embodiment of the present invention, and Fig. 10B is an explanatory diagram illustrating a terminal voltage of each phase during one-system driving when a W-phase ground fault abnormality has occurred according to the first embodiment of the present invention; Fig. 11A is an explanatory diagram illustrating an average value of terminal voltages during a single-system drive when a W-phase power fault abnormality has occurred according to the first embodiment of the present invention, and Fig. 11B is an explanatory diagram illustrating a terminal voltage of each phase during one-system driving when a W-phase power fault abnormality has occurred according to the first embodiment of the present invention; Fig. 12 is a circuit diagram illustrating a motor control device according to a second embodiment of the present invention; Fig. 13 is an explanatory diagram illustrating a pseudo neutral point voltage during one-system driving when no short-circuit abnormality has occurred according to the second embodiment of the present invention; Fig. 14 is an explanatory diagram illustrating a pseudo-neutral point voltage during single-system driving when a W-phase ground fault abnormality has occurred, according to the second embodiment of the present invention; and Fig. 15 is an explanatory diagram illustrating a pseudo neutral point voltage during single-system driving when a W-phase power fault abnormality has occurred according to the second embodiment of the present invention.

[0010] A control device for a rotating electric machine of the present invention and an electric power steering device incorporating the control device will be described below with reference to the drawings. In several embodiments described below, substantially similar configurations are denoted by the same reference numerals and will not be described repeatedly to avoid redundancy. (First embodiment)

[0011] The Fig. 1 to 11B show a first embodiment of the present invention.

[0012] As in Fig. 1, a motor control device 1 as a control device for a rotating electric machine is applied to an electric power steering device 8 that assists a steering operation by a driver, in conjunction with a motor 80 as a rotating electric machine.

[0013] Fig. 1 shows a configuration of a steering system 90 including the electric power steering device 8. The steering system 90 includes a steering wheel 91 as a steering element, a steering shaft 92, a gear transmission 96, a rack 97, wheels 98, the electric power steering device 8, and the like.

[0014] The steering wheel 91 is connected to the steering shaft 92. The steering shaft 92 is provided with a torque sensor 94 for detecting a steering torque input by the driver operating the steering wheel 91. The gear transmission 96 is provided at the tip of the steering shaft 92. The gear transmission 96 is engaged with the rack 97. A pair of wheels 98 are connected to both ends of the rack 97 via tie rods or the like.

[0015] When the driver operates the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational movement of the steering shaft 92 is converted by the gear train 96 into a linear movement of the rack 97. The pair of wheels 98 are steered at an angle in accordance with an offset of the rack 97.

[0016] The electric power steering device 8 includes the motor 80, a reduction gear 89 that reduces the rotation of the motor 80 and transmits the rotation to the steering shaft 92 or the rack 97, the motor control device 1, and the like. That is, the electric power steering device 8 of the present embodiment is of a so-called "column assist type," but may also be of a so-called "rack assist type" that transmits the rotation of the motor 80 to the rack 97.

[0017] The motor 80 outputs an auxiliary torque to assist the steering of the steering wheel 91 by the driver and is supplied with energy from a battery 5 (see Fig. 2A and Fig. 2B) as a power source to rotate the reduction gear 89 back and forth.

[0018] As in the Fig. As shown in Figures 2A to 4, the motor 80 is a brushless three-phase motor having a rotor 83, a stator 85 and two sets of windings 810, 820.

[0019] As in Fig. As shown in Figure 4, the first winding set 810 includes a U1 coil 811, a V1 coil 812, and a W1 coil 813. One ends of the coils 811, 812, and 813 are connected to a first inverter 120, and the other ends thereof are connected via a connecting part 819. Hereinafter, one end of the U1 coil 811 is referred to as a U1 terminal 111, one end of the V1 coil 812 is referred to as a V1 terminal 112, and one end of the W1 coil 813 is referred to as a W1 terminal 113.

[0020] The second winding set 820 includes a U2 coil 821, a V2 coil 822, and a W2 coil 823. One ends of the coils 821, 822, 823 are connected to a second inverter 220, and the other ends thereof are connected via a connecting part 829. Hereinafter, one end of the U2 coil 821 is referred to as a U2 terminal 211, one end of the V1 coil 812 is referred to as a V2 terminal 212, and one end of the W2 coil 823 is referred to as a W2 terminal 213.

[0021] As in the Fig. 2A and Fig. As shown in Fig. 2B, the rotor 83 is arranged radially inside the stator 85 so as to be rotatable with respect to the stator 85 about a rotation axis O. A permanent magnet 84 having the number of poles of (2×m) is arranged radially outside the rotor 83. Here, "m" is a natural number and is equal to 2 in the present embodiment. That is, the number of magnetic poles of the rotor 83 is four in the present embodiment, and one magnetic pole is arranged within a range of a mechanical angle of 90 degrees.

[0022] The coils 811 to 813, 821 to 823 are wound around the stator 85.

[0023] Fig. Figure 2B shows a schematic view of Fig. 2A from a Z direction. In the present embodiment, a case where the rotor 83 is in the Fig. 2B rotates clockwise is called a positive rotation, and a case where it rotates counterclockwise is called a negative rotation.

[0024] The phase sequence of the coils 811 to 813, 821 to 823 is shown with reference to the Fig. 2B. In the Fig. 2B, the U1 coil 811 is labeled "U1", the V1 coil 812 is labeled "V1", the W1 coil 813 is labeled "W1", the U2 coil 821 is labeled "U2", the V2 coil 822 is labeled "V2", and the W2 coil 823 is labeled "W2".

[0025] As in Fig. 2B, each of the winding sets 810, 820 corresponds to a magnetic pole, and the U1 coil 811, the U2 coil 821, the W1 coil 813, the W2 coil 823, the V1 coil 812, and the V2 coil 822 are arranged in this order, each at a mechanical angle of 15 degrees from a reference line B.

[0026] Further, in the present embodiment, the U1 coil 811, the U2 coil 821, the V1 coil 812, and the V2 coil 822 are wound in a first direction, and the W1 coil 813 and the second coil 823 are wound in a second direction opposite to the first direction.

[0027] A phase sequence with respect to the electrical angle is equal to the Fig. 3. An angle formed by a U-phase of a first system 101 and a d-axis, which will be described later, is referred to as a first electrical angle θ1, and an angle formed by a U-phase of a second system 201 and the d-axis is referred to as a second electrical angle θ2. Equation (1-1) shows the relationship between the first electrical angle θ1 and the second electrical angle θ2. Furthermore, equations (1-2) and (1-3) each show the relationship between the first electrical angle θ1 or the second electrical angle θ2 and an electrical angle θe, which will be described later. In this description, the unit of the electrical angle is referred to as [degree] or [°], respectively. θ1−θ2=30 θ1=θe+15 θ2=θe−15

[0028] Furthermore, equations (2-1), (2-2), (2-3) show induced voltages of the respective phases. Eun=−sin(θn) Evn=−sin(θn−120) Ewn=−sin(θn+120)

[0029] In the respective equations, "n" is equal to 1 or 2. When "n" is equal to 1, induced voltages Eu1, Ev1, Ew1 are induced voltages generated in the respective phases of the first winding set 810. When "n" is equal to 2, induced voltages Eu2, Ev2, Ew2 are induced voltages generated in the respective phases of the second winding set 820.

[0030] As in Fig. As shown in Figure 4, the motor control device 1 controls the drive of the motor 80 by pulse width modulation control or the like. The motor control device 1 includes inverters 120, 220, terminal voltage detection parts 140, 240, capacitors 170, 270, capacitor voltage detection parts 175, 275, power source relay parts 180, 280, a rotation angle sensor 30, a control part 40, and the like. It should be noted that, in the Fig. 4, a control line and the like, as applicable, are omitted to simplify the figure.

[0031] In the present embodiment, the first system 101 is constructed of the first winding set 810 and the electronic components provided corresponding to the first winding set 810, such as the first inverter 120, each of the detection parts 130, 140, 175, the first capacitor 170, and the first power source relay part 180. Furthermore, the second system 201 is constructed of the second winding set 820 and the electronic components provided corresponding to the second winding set 820, such as the second inverter 220, each of the detection parts 230, 240, 275, the second capacitor 270, and the second power source relay part 280.

[0032] Hereinafter, regarding a configuration with a three-digit number, if the hundreds place is "1," this means that the configuration is included in the first system 101, and if the hundreds place is "2," this means that the configuration is included in the second system 202. Furthermore, if the last two digits of the arrangement included in the first system 101 are the same as those in the configuration included in the second system 201, this means that the configurations are the same.

[0033] Below, the configuration and control according to the first system 101 are mainly described, and a description of the configuration according to the second system 201 is omitted as appropriate. Note that a configuration name or value according to the second system 201 is obtained by changing an index "1" of the name according to the first system 101 to "2", such as changing from "first" to "second" or from "U1" to "U2".

[0034] The first inverter 120 is a three-phase inverter and has an upper arm U1 element 121, an upper arm V1 element 122, an upper arm W1 element 123, a lower arm U1 element 124, a lower arm V1 element 125 and a lower arm W1 element 126.

[0035] Hereinafter, elements 121 to 126 and 221 to 226 are referred to as “SW elements”.

[0036] The SW elements 121 to 126, 221 to 226 are all metal oxide semiconductor field effect transistors (MOSFETs), but may also be insulated gate bipolar transistors (IGBTs), thyristors or the like.

[0037] Drains of the upper arm elements 121, 122, 123, i.e., elements 121, 122, 123, are connected to a first positive-side bus 116, i.e., a first bus 116. Sources of the upper arm elements 121, 122, 123 are connected to drains of the respective pairs of lower arm elements 124, 125, 126. Sources of the lower arm elements 124, 125, 126 are connected to a first negative-side bus 117, i.e., a first bus 117.

[0038] A node of the paired U-phase element of the upper arm 121 and the lower arm 124 is connected to the U1 terminal 111. A node of the paired V-phase element of the upper arm 122 and the lower arm 125 is connected to the V1 terminal 112. A node of the paired W-phase element of the upper arm 123 and the lower arm 126 is connected to the W1 terminal 113.

[0039] The first positive-side bus 116 is a high-potential-side wiring for connecting the high-potential sides of the upper-arm elements 121 to 123 to a positive electrode of the battery 5, and is located on the downstream side of the first relay part 180. The downstream side of the first relay part 180 is assumed to be the side opposite to the battery 5. The first negative-side bus 117 is a low-potential-side wiring for connecting the low-potential sides of the lower-arm elements 124 to 126 to a negative electrode of the battery 5 or a ground.

[0040] The first current detection part 130 includes current sensors 131, 132, and 133. The current sensors 131 to 133 are respectively provided between the first lower arm elements 124 to 126 and the first negative-side bus 117 and detect respective phase currents Iu1, Iv1, and Iw1 flowing into the respective phases of the first winding set 810. The current sensors 131 to 133 of the present embodiment are all shunt resistors. The voltages across the ends of the current sensors 131 to 133 are output to the control part 40 via operational amplifiers 134, 135, and 136 as detection values ​​corresponding to the respective phase currents Iu1, Iv1, and Iw1.

[0041] The first terminal voltage detection part 140 has a U1 terminal voltage detection part 141, a V1 terminal voltage detection part 144 and a W1 terminal voltage detection part 147.

[0042] The U1 terminal voltage detection part 141 includes resistors 142, 143, which are partial resistors connected to the U1 terminal 111 and the first negative-side bus 117. A voltage of a node of the resistors 142, 143 is output to the control part 40 as a U1 terminal voltage detection value Vu1_d, which is a detection value corresponding to a U1 terminal voltage Vu1 of the U1 terminal 111.

[0043] The V1 terminal voltage detection part 144 includes resistors 145, 146, which are partial resistors connected to the V1 terminal 112 and the first negative-side bus 117. A voltage of a node of the resistors 145, 146 is output to the control part 40 as a V1 terminal voltage detection value Vv1_d, which is a detection value corresponding to a V1 terminal voltage Vv1 of the V1 terminal 112.

[0044] The W1 terminal voltage detection part 147 includes resistors 148, 149 that are partial resistors connected to the W1 terminal 113 and the first negative-side bus 117. A voltage of a node of the resistors 148, 149 is output to the control part 40 as a W1 terminal voltage detection value Vw1_d, which is a detection value corresponding to a W1 terminal voltage Vw1 of the W1 terminal 113.

[0045] In the second terminal voltage detection part 240, a voltage of a node of the resistors 242, 243 is output to the control part 40 as a U2 terminal voltage detection value Vu2_d, which is a detection value corresponding to a terminal voltage Vu2 of the U2 terminal 211. A voltage of a node of the resistors 245, 246 is output to the control part 40 as a V2 terminal voltage detection value Vv2_d, which is a detection value corresponding to a terminal voltage Vv2 of the V2 terminal 212. A voltage of a node of the resistors 248, 248 is output to the control part 40 as a W2 terminal voltage detection value Vw2_d, which is a detection value corresponding to a terminal voltage Vw2 of the W2 terminal 213.

[0046] In the control part 40, the respective terminal voltage detection values ​​are converted based on a resistance value ratio to calculate the respective terminal voltages.

[0047] Since the respective terminal voltage detection values ​​before conversion are values ​​convertible into terminal voltages, it is considered that the first terminal voltage detection part 140 has detected the terminal voltages Vu1, Vv1, Vw1, and the second terminal voltage detection part 240 has detected the terminal voltages Vu2, Vv2, Vw2.

[0048] A first boost resistor group 150 includes a U1 boost resistor 151, a V1 boost resistor 152, and a W1 boost resistor 153. The U1 boost resistor 151 is connected to the first positive-side bus 116 and the U1 terminal voltage detection part 141. The V1 boost resistor 152 is connected to the first positive-side bus 116 and the V1 terminal voltage detection part 144. The W1 boost resistor 153 is connected to the first positive-side bus 116 and the W1 terminal voltage detection part 147.

[0049] A resistance value of each of the resistors constituting the first terminal voltage detection part 140 and a resistance value of each of the resistors constituting the first boost resistor group 150 can be determined as appropriate. In the present embodiment, the resistance values ​​of all these resistors are assumed to be equal.

[0050] The first capacitor 170 is connected to the first positive side bus 116 and the first negative side bus 117 and stores charges to assist in supplying power to the first inverter 120 and suppressing a noise component such as a current surge.

[0051] The first capacitor voltage detection part 175 includes resistors 176, 177, which are partial resistors connected to the first positive-side bus 116 and the first negative-side bus 117. A voltage of a node of the resistors 176, 177 is output to the control part 40 as a detection value in accordance with a first capacitor voltage Vc1, which is a voltage of the first capacitor 170. It should be noted that the first capacitor voltage Vc1 can be assumed to be a voltage of the first positive-side bus 116 or a voltage after relaying, which is a voltage on the downstream side of the first relay part 180.

[0052] The first power source relay part 180 has a first power source relay part 181 and a first reverse polarity protection relay 182.

[0053] The first power source relay part 181 is provided between the battery 5 and the first inverter 120, the first terminal voltage detection part 140, the first capacitor 170 and the first capacitor voltage detection part 175 and can interrupt the power supply from the battery 5 to the first inverter 120.

[0054] The first reverse polarity protection relay 182 is connected in series with the first power source relay part 181 such that the directions of the first power source relay part 181 and the parasitic diode are opposite to each other. The first reverse polarity protection relay 182 prevents reverse current from flowing when the battery 5 or the like is mistakenly connected in the reverse direction.

[0055] Relays 181 and 182 in the present embodiment are both MOSFETs, but are not limited to solid-state relays; they can also be mechanical relays. When solid-state relays or mechanical relays without a parasitic diode are used, the reverse polarity protection relay 182 can be omitted.

[0056] The rotation angle sensor 30 detects the electrical angle θe of the motor 80. The detection value of the rotation angle sensor 30 is output to the control part 40.

[0057] As in the Fig. 4 and Fig. As shown in Figure 5, the control section 40 is mainly composed of a microcomputer and the like. Each processing in the control section 40 may be software processing executed by a central processing unit (CPU) executing a pre-stored program stored in a storage device such as a read-only memory (ROM), or hardware processing executed by a dedicated electronic circuit.

[0058] The control part 40 controls the drive of the motor 80 by controlling an on / off operation of the upper arm elements 121 to 123, 211 to 213 and the lower arm elements 124 to 126, 214 to 216, based on a torque detection value detected by the torque sensor 94 (see Fig. 1), a detection value in accordance with the electrical angle θe detected by the rotation angle sensor 30, and the like.

[0059] As in Fig. 5, the control part 40 includes, as a functional block, a first inverter control part 41, a second inverter control part 42, a relay control part 43, an abnormality determination part 45, and the like.

[0060] The first inverter control part 41 includes a three-phase / two-phase conversion part 410, a correction current calculation part 411, a switching part (SW) 412, a correction part 413, subtractors 414, 415, a controller 416, a two-phase / three-phase conversion part 417, an operation calculation part 418, and a signal generation part 419.

[0061] The second inverter control part 42 includes a three-phase / two-phase conversion part 420, a correction current calculation part 421, a switching part (SW) 422, a correction part 423, subtractors 424, 425, a controller 426, a two-phase / three-phase conversion part 427, an operation calculation part 428, and a signal generation part 429.

[0062] If the last digits of the three-digit numbers are the same between each calculation part of the first inverter control part 41 and each calculation part of the second inverter control part 42, this means that these calculation parts are the same. Hereinafter, the first inverter control part 41 is mainly described, and the description of the second inverter control part 42 is omitted where applicable.

[0063] The three-phase / two-phase conversion part 410 performs a dq transformation based on the electrical angle θ on each of the phase currents Iu1, Iv1, Iw1 calculated based on the detection value of the first current detection part 130 to calculate a d-axis current detection value Id1 and a q-axis current detection value Iq1.

[0064] The correction current calculation part 411 calculates a q-axis current correction value Iq1_a for correcting a torque ripple that occurs due to a back electromotive force of the motor 80 in accordance with an abnormality location in the second system 201 determined by the abnormality determination part 45.

[0065] The switching part 412 switches whether to output or not to output the q-axis current correction value Iq1_a. If a switching flag FlgB2 output by the abnormality determination part 45 has been set, the switching part 412 outputs the q-axis current correction value Iq1_a. If the switching flag FlgB2 has not been set, the switching part 412 does not output the q-axis current correction value Iq1_a.

[0066] It should be noted that, as for the second inverter control part 42, the correction current calculation part 421 calculates a q-axis current correction value Iq2_a for correcting a torque ripple occurring due to a back electromotive force of the motor 80 in accordance with a short-circuit location in the first system 101 determined by the abnormality determination part 45.

[0067] The switching part 422 switches whether to output or not to output the q-axis current correction value Iq2_a. If a switching flag FlgB1 output by the abnormality determination part 45 has been set, the switching part 422 outputs the q-axis current correction value Iq2_a. If the switching flag FlgB1 has not been set, the switching part 422 does not output the q-axis current correction value Iq2_a.

[0068] The processing performed by the correction current calculation parts 411, 421 and the switching parts 412, 422 will be described in more detail below.

[0069] The correction part 413 corrects a q-axis current command value Iq1* using the current correction value Iq1_a output from the switching part 412. It should be noted that when the current correction value Iq1_a is not output, the q-axis current correction value Iq1_a is assumed to be 0. That is, in this case, the q-axis current command value Iq1* is not corrected, and the q-axis current command value Iq1* is taken as a corrected q-axis current command value Iq**. In the present embodiment, the correction part 413 is an adder, and the correction part 413 adds the q-axis current correction value Iq1_a to the q-axis current command value Iq1* to calculate the corrected q-axis current command value Iq1**.

[0070] The d-axis subtractor 414 calculates a d-axis current deviation ΔId1, which is a deviation between the d-axis current command value Id1* and the d-axis current detection value Id1 that is fed back.

[0071] The q-axis subtractor 415 calculates a q-axis current deviation ΔIq1, which is a deviation between the corrected q-axis current command value Iq1** and the q-axis current detection value Iq1 that is fed back.

[0072] The controller 416 calculates a d-axis voltage command value Vd1* and a q-axis voltage command value Vq1* using a PI calculation or the like such that the current deviations ΔId1, ΔIq1 approach 0.

[0073] The two-phase / three-phase conversion part 417 performs an inverse dq transformation based on the electrical angle θ on the d-axis voltage command value Vd1* and a q-axis voltage command value Vq1* to calculate a U1 voltage command value Vu1*, a V1 voltage command value Vv1*, and a W1 voltage command value Vw1*.

[0074] The duty calculation part 418 performs modulation processing and the like based on the voltage command values ​​Vu1*, Vv1*, Vw1* to calculate the duty command values ​​Du1, Dv1, Dw1.

[0075] The signal generating part 419 generates an upper U1 drive signal U1_H for instructing on / off of the upper arm U1 element 121 and a lower U1 drive signal U1_L for instructing on / off of the lower arm U1 element 124 based on the operation command value Du1 by means of a triangular wave comparison or the like.

[0076] The signal generating part 419 generates an upper V1 drive signal V1_H for instructing on / off of the upper arm V1 element 122 and a lower V1 drive signal V1_L for instructing on / off of the lower arm V1 element 125 based on the operation command value Dv1 by the triangular wave comparison or the like.

[0077] The signal generating part 419 generates an upper W1 drive signal W1_H for instructing on / off of the W1 element of the upper arm 123 and a lower W1 drive signal W1_L for instructing on / off of the W1 element of the lower arm 126 based on the operation command value Dw1 by the triangular wave comparison or the like.

[0078] The same processing is also performed in the second inverter control part 42 to generate an upper U2 drive signal U2_H, a lower U2 drive signal U2_L, an upper V2 drive signal V2_H, a lower V2 drive signal V2_L, an upper W2 drive signal W2_H and a lower W2 drive signal W2_L.

[0079] The drive of the motor 80 is controlled by controlling the first inverter 120 and the second inverter 220 based on the generated drive signals.

[0080] The relay control part 43 controls the ON / OFF operation of the relays 181, 182, 281, 282. In the present embodiment, the relays 181, 182 are turned off when an abnormality flag FlgA1 has been set, and the relays 281, 282 are turned off when an abnormality flag FlgA2 has been set.

[0081] The abnormality determination part 45 determines whether the abnormality has occurred in the first system 101 or in the second system 201 based on each of the phase currents Iu1, Iv1, Iw1, Iu2, Iv2, Iw2. For example, when the sum of three phases of Iu1, Iv1, Iw1 is not equal to 0, that is, when a relationship of Iu1 + Iv1 + Iw1 ≠ 0 is satisfied, it can be determined that the abnormality has occurred in the first system 101. Similarly, when the sum of three phases of Iu2, Iv2, Iw2 is not equal to 0, that is, when a relationship of Iu2 + Iv2 + Iw2 ≠ 0 is satisfied, it can be determined that the abnormality has occurred in the second system 201.

[0082] Hereinafter, a system in which an abnormality has occurred is appropriately regarded as a faulty system, and a system that is normal is regarded as a normal system.

[0083] If the abnormality has occurred in the first system 101 while the second system 201 is normal, the control of the motor 80 is continued in the normal second system 201.

[0084] When the abnormality has occurred in the first system 101, the abnormality determination part 45 outputs the abnormality flag FlgA1 to the signal generation part 419. The signal generation part 419 sets the drive signals U1_H, U1_L, V1_H, V1_L, W1_H, W1_L to OFF commands in accordance with the drive of the first inverter 120 to turn off all of the SW elements 121 to 126 of the first inverter 120.

[0085] Furthermore, the abnormality determination part 45 outputs the abnormality flag FlgA1 to the relay control part 43. The relay control part 43 turns off the relays 181, 182.

[0086] If the first system 101 is normal while the abnormality has occurred in the second system 201, the control of the motor 80 in the normal first system 101 is continued.

[0087] When the abnormality has occurred in the second system 201, the abnormality determination part 45 outputs the abnormality flag FlgA2 to the signal generation part 429. The signal generation part 429 sets the drive signals U2_H, U2_L, V2_H, V2_L, W2_H, W2_L to OFF commands in accordance with the drive of the second inverter 220 to turn off all of the SW elements 221 to 226 of the second inverter 220.

[0088] Furthermore, the abnormality determination part 45 outputs the abnormality flag FlgA2 to the relay control part 43. The relay control part 43 turns off the relays 281, 282.

[0089] A short-circuit abnormality is described below. An abnormality in which the U1 coil 811 is short-circuited to the first positive-side bus 116 or the first negative-side bus 117 is referred to as a U1 short-circuit abnormality. The U1 short-circuit abnormality includes a U1 power fault abnormality in which the U1 coil 811 is short-circuited to the first positive-side bus 116, and a U1 ground fault abnormality in which the U1 coil 811 is short-circuited to the first negative-side bus 117.

[0090] The U1 power fault abnormality includes a case where the U1 coil 811 itself is short-circuited to the first positive-side bus 116, and a case where a short-circuit fault has occurred in the U1 upper-arm element 121. The short-circuit fault of the U1 upper-arm element 121 includes a case where the element itself is short-circuited and a case where the drive signal U1_H is faulty.

[0091] The U1 ground fault abnormality includes a case where the U1 coil 811 itself is short-circuited to the first negative-side bus 117, and a case where a short-circuit fault has occurred in the U1 lower-arm element 124. The U1 lower-arm element 124 short-circuit fault includes a case where the element itself is short-circuited and a case where the drive signal U1_L is faulty.

[0092] An abnormality in which the current between the V1 coil 812 and the first positive-side bus 116 or the first negative-side bus 117 cannot be interrupted is called a V1 short-circuit abnormality. The V1 short-circuit abnormality includes a V1 power fault abnormality and a V1 ground fault abnormality.

[0093] An abnormality in which the current between the W1 coil 813 and the first positive-side bus 116 or the first negative-side bus 117 cannot be interrupted is called a W1 short-circuit abnormality. The W1 short-circuit abnormality includes a W1 power fault abnormality and a W1 ground fault abnormality.

[0094] The details of the power fault abnormality and the ground fault abnormality of the V phase and the W phase are the same as those of the power fault abnormality and the ground fault abnormality of the U phase.

[0095] A short-circuit abnormality of each phase on the second system 201 side is the same as the above and will not be described repeatedly below.

[0096] When the driving of the motor 80 is continued using the second system 201 in a state where the short-circuit abnormality has occurred in the first system 101, a backflow current is generated by a back electromotive force, whereby a torque ripple occurs.

[0097] Similarly, when the driving of the motor 80 is continued using the first system 101, in a state where the short-circuit abnormality has occurred in the second system 201, a backflow current is generated by a back electromotive force, whereby a torque ripple occurs.

[0098] In the present embodiment, the abnormality determination part 45 determines a phase in which the power fault abnormality or the ground fault abnormality occurred based on a terminal voltage of the faulty system with the motor 80 in the rotating state. Furthermore, a corresponding amount of torque ripple is compensated in accordance with the short-circuit location on the normal system side to reduce the torque ripple due to the back electromotive force during single-system driving.

[0099] The following describes abnormality determination processing in the present embodiment with reference to the Fig. 6 is described. In the figure, the first system 101 is denoted by "System 1" and the second system 201 is denoted by "System 2." Herein, it is assumed that at least one of the first system 101 and the second system 201 is normal. If both the first system 101 and the second system 202 are faulty, the relay parts 180, 280 are turned off to stop the motor 80. Herein, the relay parts 180, 280 are assumed to be normal. It is assumed that an abnormality of the relay parts 180, 280 is monitored by separate processing.

[0100] In step S11, the abnormality determination part 45 first determines whether the first system 101 is faulty. Hereinafter, "step" of step S11 is omitted and simply denoted by reference character "S." This also applies to the other steps. If the first system 101 is determined to be normal (S11: NO), processing proceeds to S21. If the first system 101 is determined to be faulty (S11: YES), processing proceeds to S12.

[0101] In S12, to which the processing proceeds when the first system 101 is faulty and the second system 201 is normal, the abnormality determination part 45 sets the abnormality flag FlgA1 and outputs the flag to the signal generation part 419 and the relay control part 43.

[0102] In S13, the relay control part 43 turns off the relays 181, 182 to stop the power supply from the battery 5 to the first inverter 120 side. Furthermore, the signal generation part 419 sets the drive signals U1_H, U1_L, V1_H, V1_L, W1_H, W1_L to OFF commands to turn off all of the SW elements 121 to 126 of the first inverter 120. In the figure, the drive signals U1_H, U1_L, V1_H, V1_L, W1_H, W1_L are denoted by "(U, V, W)1_(H, L)".

[0103] In S14, the abnormality determination part 45 turns off the relays 181, 182, and the abnormality determination part 45 determines whether a waiting time Ts has elapsed. The waiting time Ts is the time required for the first capacitor voltage Vc1 to fall to an abnormality determination upper limit voltage by discharging the first capacitor 170. It should be noted that the first capacitor voltage Vc1 is used instead of the elapsed time since the relays 181, 182 are turned off, and the positive determination can be made in the case where the first capacitor voltage Vc1 becomes less than or equal to the upper limit voltage, based on the first capacitor voltage Vc1. When it is determined that the waiting time Ts has not elapsed since the relays 181, 182 were turned off (S14: NO), that is, when it is estimated that the first capacitor voltage Vc1 is higher than the abnormality determination upper limit voltage, this determination processing is repeated.When it is determined that the waiting time Ts has elapsed since the relays 181, 182 were turned off (S14: YES), that is, when it is estimated that the first capacitor voltage Vc1 is less than or equal to the abnormality determination upper limit voltage, the processing proceeds to S15.

[0104] In S15, the abnormality determination part 45 executes the short-circuit location determination processing for the first system 101. If a short-circuit phase is one phase, the switching flag FlgB1 is set. If the short-circuit phase is not determined, or if multiple short-circuit phases are determined, the switching flag FlgB1 is not set. The short-circuit location determination processing is described below with reference to a Fig. The subroutine shown in Figure 7 is described in more detail.

[0105] In S16, to which processing proceeds after the short-circuit location determination processing is completed, the abnormality determination part 45 determines whether the switching flag FlgB1 has been set. If it is determined that the switching flag FlgB1 has not been set (S16: NO), processing returns to S15 and the short-circuit location determination processing is repeated. If it is determined that the switching flag FlgB1 has been set (S16: YES), processing proceeds to S17.

[0106] In S17, torque compensation is performed to compensate for a torque ripple in the second system 201, which is normal, in accordance with a fault location in the first system 101. Specifically, the switching part 422 outputs the q-axis current correction value Iq2_a calculated in the correction current calculation part 421.

[0107] In the correction current calculation part 421, the q-axis current correction value Iq2_a is calculated based on the first electrical angle θ1, using a map in accordance with the fault location in the first system 101. The Fig. Figures 8A to 8F show the figure or characteristic curve used to calculate the q-axis current correction value Iq2_a. Fig. 8A to 8F show the q-axis current correction value Iq2_a during positive rotation, where Fig. 8A describes the time of the U1 energy fault abnormality, Fig. 8B describes the time of the V1 energy error abnormality, Fig. 8C describes the time of the W1 energy error abnormality, Fig. 8D describes the time of the U1 mass fault abnormality, Fig. 8E describes the time of the V1 mass defect abnormality and Fig. 8F describes the time of the W1 mass error anomaly. During a negative rotation, a multiplication by -1 occurs to obtain a positive / negative inversion value.

[0108] In the figures, “n” in “θn” is equal to “1” or “2” and thus means that “θn” is the first electrical angle θ1 or the second electrical angle θ2. Furthermore, in the Fig. 8A to 8F, the q-axis d-current correction value Iqn_a is simply referred to as “correction value”.

[0109] Below we refer again to the Fig. 6. In S21, to which processing proceeds when the first system 101 is determined to be normal (S11: NO), it is determined whether the second system 201 is faulty. If the second system 202 is determined to be normal (S21: NO), processing returns to S11. That is, if the first system 101 and the second system 201 are both normal, the determination processing of S11 and S21 is repeated. If the second system 201 is determined to be faulty (S21: YES), processing proceeds to S22.

[0110] Since the processing of S22 to S27 corresponds to the processing of S12 to S17, it is not described repeatedly below, as applicable.

[0111] In S22, to which the processing proceeds when the second system 201 is faulty and the first system 101 is normal, the abnormality determination part 45 sets the abnormality flag FlgA2, and the abnormality determination part 45 outputs the flag to the signal generation part 419 and the relay control part 43.

[0112] In S23, the relay control section 43 turns off relays 281, 282 to stop the power supply from the battery 5 to the second inverter 220. The signal generation section 429 sets the drive signals U2_H, U2_L, V2_H, V2_L, W2_H, W2_L to OFF commands. In the figure, the drive signals U2_H, U2_L, V2_H, V2_L, W2_H, W2_L are denoted by "(U, V, W)2_(H, L)".

[0113] In S24, the abnormality determination part 45 determines whether the waiting time Ts has elapsed. If it is determined that the waiting time Ts has not elapsed (S24: NO), this determination processing is repeated. If it is determined that the waiting time Ts has elapsed (S24: YES), the processing proceeds to S25.

[0114] In S25, the abnormality determination part 45 executes the short-circuit location determination processing for the second system 201. If a short-circuit phase is one phase, the switching flag FlgB2 is set. If the short-circuit phase is not determined, or if multiple short-circuit phases are determined, the switching flag FlgB2 is not set.

[0115] In S26, to which processing proceeds after the short-circuit location determination processing is completed, the abnormality determination part 45 determines whether the switching flag FlgB2 has been set. If the switching flag FlgB2 has not been set (S26: NO), the short-circuit location determination processing is repeated. If it is determined that the switching flag FlgB2 has been set (S26: YES), processing proceeds to S27.

[0116] In S27, torque compensation is performed to compensate for a torque ripple in the first system 101, which is normal, in accordance with a fault location in the second system 201. Specifically, the switching part 412 outputs the q-axis current correction value Iq1_a calculated in the correction current calculation part 411.

[0117] In the correction current calculation part 411, the q-axis current correction value Iq1_a is calculated based on the second electrical angle θ2, using the figure (see Fig. 8A to 8F) in accordance with the fault location in the second system 201.

[0118] Fig. 7 shows a subroutine corresponding to the short-circuit location determination processing. In S15, a ratio of n = 1 is assumed, and the short-circuit location in the first system 101 is determined based on a first terminal voltage average value Vt1, which will be described later. In S25, a ratio of n = 2 is assumed, and the short-circuit location in the second system 201 is determined based on a second terminal voltage average value Vt2, which will be described later.

[0119] The following mainly describes the short-circuit location determination processing in the first system 101. Note that, in the short-circuit location determination processing in the second system 201, the second terminal voltage average value Vt2 is used instead of the first terminal voltage average value Vt1, and the second electrical angle θ2 is used instead of the first electrical angle θ1.

[0120] In S501, it is determined whether the motor 80 is constantly rotating. In the present embodiment, if a state in which the rotational speed of the motor 80 is within a predetermined range is maintained for at least a predetermined period of time, it is assumed that the motor 80 is constantly rotating and the determinable condition is satisfied. The "predetermined range" in accordance with the rotational speed of the motor 80 is adjustable as appropriate, and is set, for example, to greater than or equal to 500 [rpm] and less than or equal to 1000 [rpm]. The continuation time is also adjustable as appropriate. If it is determined that the motor 80 is constantly rotating (S501: YES), processing proceeds to S503. If it is determined that the motor 80 is not constantly rotating (S501: NO), processing proceeds to S502.

[0121] In S502, each counter is reset in accordance with the short-circuit location determination, after which processing returns to the main flow or main program.

[0122] In S503, to which processing proceeds when it is determined that the motor 80 is constantly rotating (S501: YES), the abnormality determination part 45 calculates the first terminal voltage average value Vt1, which is an average value of the terminal voltages Vu1, Vv1, Vw1. The first terminal voltage average value Vt1 is calculated using Equation (3-1). Equation (3-1) takes as an example the case where the resistors 142, 143, 145, 146, 148, and 149 have the same resistance values. A coefficient by which the terminal voltage detection values ​​Vu1_d, Vv1_d, and Vw1_d are multiplied is determined, as applicable, in accordance with the resistance values. This also applies to Equation (3-2). Vt1=(Vu1+Vv1+Vw1) / 3 =(Vu1_d×2+Vv1_d×2+Vw1_d×2) / 3

[0123] When the short-circuit location in the second system 201 is to be determined, the abnormality determination part 45 calculates the second terminal voltage average value Vt2. The second terminal voltage average value Vt2 is calculated using Equation (3-2). Vt2=(Vu2+Vv2+Vw2) / 3 =(Vu2_d×2+Vv2_d×2+Vw2_d×2) / 3

[0124] Furthermore, when the short circuit location is to be determined in the first system 101, since the relay part 180 is turned off and the SW elements 121 to 126 have OFF commands, the terminal voltages Vu1, Vv1, Vw1 are caused by a counter electromotive force generated by the rotation of the motor 80. Furthermore, when the short circuit is to be determined in the second system 201, since the SW elements 221 to 226 have OFF commands, the terminal voltages Vu2, Vv2, Vw2 are caused by a counter electromotive force generated by the rotation of the motor 80.

[0125] In S504, if the first electrical angle θ1 is within a U-phase ground fault determination range, the abnormality determination part 45 performs a U-phase ground fault determination. The U-phase ground fault determination range during positive rotation of the motor 80 is 240 ≤ θ1 ≤ 300, and the U-phase ground fault determination range during negative rotation of the motor 80 is 60 ≤ θ1 ≤ 120. The ground fault determination range is determined, as applicable, in accordance with a phase offset of the first winding set 810 and the definition of the electrical angle. This also applies to the power fault determination range.

[0126] When the first terminal voltage average value Vt1 is less than or equal to a ground fault determination threshold Vth_g when the first electrical angle θ1 is within the U-phase ground fault determination range, the abnormality determination part 45 considers the U-phase to have a ground fault. When a detected fault or the like is considered, the ground fault determination threshold Vth_g is set to any predetermined value (such as 0.3 [V]) close to 0. When the first electrical angle θ1 is outside the U-phase ground fault determination range, the U-phase ground fault determination is not performed. This also applies to the V-phase and W-phase ground faults.

[0127] If the U phase does not have a ground fault, or if the ground fault determination is not made (S504: NO), processing proceeds to S506. If the U phase is determined to have a ground fault (S504: YES), processing proceeds to S505.

[0128] In S505, the abnormality determination part 45 increments a U-phase ground fault counter U1_g.

[0129] In S506, if the first electrical angle θ1 is within a U-phase power error determination range, the abnormality determination part 45 performs a U-phase power error determination. The U-phase power error determination range during positive rotation of the motor 80 is 60 ≤ θ1 ≤ 120, and the U-phase power error determination range during negative rotation of the motor 80 is 240 ≤ θ1 ≤ 300.

[0130] When the first terminal voltage average value Vt1 is greater than or equal to a power failure determination threshold Vth_p when the first electrical angle θ1 is within the U-phase power failure determination range, the abnormality determination part 45 considers the U-phase to have a power failure. When a detected failure or the like is taken into account, the power failure determination threshold Vth_p is determined, as appropriate, in accordance with the first capacitor voltage Vc1 to assume a value close to the first capacitor voltage Vc1. In the present embodiment, the power failure determination threshold Vth_p is a value obtained by multiplying the first capacitor voltage Vc1 by a predetermined coefficient (such as 0.9).When determining the short-circuit location in the second system 202, a second capacitor voltage Vc2 is used instead of the first capacitor voltage Vc1. If the first electrical angle θ1 is outside the U-phase power fault determination range, the U-phase power fault determination is not performed. This also applies to V-phase and W-phase power faults.

[0131] If the U phase does not have a power fault, or if the power fault determination is not made (S506: NO), processing proceeds to S508. If the U phase is determined to have a power fault (S504: YES), processing proceeds to S507.

[0132] In S507, the abnormality determination part 45 increments a U-phase power error counter U1_p.

[0133] In S508, if the first electrical angle θ1 is within a V-phase ground fault determination range, the abnormality determination part 45 performs a V-phase ground fault determination. The V-phase ground fault determination range during positive rotation of the motor 80 is 0 ≤ θ1 ≤ 60, and the V-phase ground fault determination range during negative rotation of the motor 80 is 180 ≤ θ1 ≤ 240.

[0134] When the first terminal voltage average value Vt1 is less than or equal to a ground fault determination threshold value Vth_g in the case where the first electrical angle θ1 is within the V-phase ground fault determination range, the abnormality determination part 45 considers the V-phase to have a ground fault.

[0135] If the V phase does not have a ground fault, or if the ground fault determination is not made (S508: NO), processing proceeds to S510. If the V phase is determined to have a ground fault (S508: YES), processing proceeds to S509.

[0136] In S509, the abnormality determination part 45 increments a V-phase ground error counter V1_g.

[0137] In S510, if the first electrical angle θ1 is within a V-phase power error determination range, the abnormality determination part 45 performs a V-phase power error determination. The V-phase power error determination range during positive rotation of the motor 80 is 180 ≤ θ1 ≤ 240, and the V-phase power error determination range during negative rotation of the motor 80 is 0 ≤ θ1 ≤ 60.

[0138] When the first terminal voltage average value Vt1 is greater than or equal to the power failure determination threshold value Vth_p in the case where the first electrical angle θ1 is within the V-phase power failure determination range, the abnormality determination part 45 considers the V-phase to have a power failure.

[0139] If the V phase does not have a power error, or if the power error determination is not made (S510: NO), processing proceeds to S512. If the V phase is determined to have a power error (S510: YES), processing proceeds to S511.

[0140] In S511, the abnormality determination part 45 increments a V-phase power error counter V1_p.

[0141] In S512, if the first electrical angle θ1 is within a W-phase ground fault determination range, the abnormality determination part 45 performs a W-phase ground fault determination. The W-phase ground fault determination range during positive rotation of the motor 80 is 120 ≤ θ1 ≤ 180, and the W-phase ground fault determination range during negative rotation of the motor 80 is 300 ≤ θ1 ≤ 360.

[0142] When the first terminal voltage average value Vt1 is less than or equal to a ground fault determination threshold value Vth_g in the case where the first electrical angle θ1 is within the W-phase ground fault determination range, the abnormality determination part 45 considers the W-phase to have a ground fault.

[0143] If the W phase does not have a ground fault, or if the ground fault determination is not made (S512: NO), processing proceeds to S514. If the W phase is determined to have a ground fault (S512: YES), processing proceeds to S513.

[0144] In S513, the abnormality determination part 45 increments a W-phase ground error counter W1_g.

[0145] In S514, if the first electrical angle θ1 is within a W-phase power error determination range, the abnormality determination part 45 performs W-phase power error determination. The W-phase power error determination range during positive rotation of the motor 80 is 300 ≤ θ1 ≤ 360, and the W-phase power error determination range during negative rotation of the motor 80 is 120 ≤ θ1 ≤ 180.

[0146] When the first terminal voltage average value Vt1 is greater than or equal to the energy error determination threshold value Vth_p in the case where the first electrical angle θ1 is within the W-phase energy error determination range, the abnormality determination part 45 considers the W-phase to have an energy error.

[0147] If the W phase does not have a power error, or if the power error determination is not made (S514: NO), processing proceeds to S516. If the W phase is determined to have a power error (S514: YES), processing proceeds to S515.

[0148] In S515, the abnormality determination part 45 increments a W-phase energy error counter W1_p.

[0149] It should be noted that, in the Fig. 7, the U-phase ground fault, the U-phase power fault, the V-phase ground fault, the V-phase power fault, the W-phase ground fault, the W-phase power fault are determined in this order in S504 to S515, but the order may be indeterminate or changed.

[0150] In S516, the abnormality determination part 45 determines whether the number of counters with a count value C greater than an abnormality decision value Cd is one or more than one. If it is determined that the number of ground fault counters or power fault counters with a count value C greater than the abnormality decision value Cd is more than one (S516: YES), the switching flag FlgB1 is not set, and the short-circuit location determination processing is terminated. That is, if the count value C in multiple counters is greater than the abnormality decision value Cd and multiple phases are determined as the short-circuit phases, the short circuit is not caused by a short circuit at the above location, but the short circuit may be caused by another abnormality, such as a short circuit of a partial resistor on the high-potential side of the terminal voltage detection part or a short circuit of the step-up resistor.Accordingly, if torque compensation is performed considering that multiple phases have been short-circuited, even though the short circuit is caused by another abnormality, this may lead to a further increase in torque ripple. Therefore, in the present embodiment, if multiple phases are determined to be short-circuited, torque compensation is not performed to prevent the torque ripple from increasing.

[0151] When it is determined that the number of counters whose count value C is above the abnormality decision value Cd is less than or equal to 1 (S516: NO), the processing proceeds to S517.

[0152] In S517, the abnormality determination part 45 determines whether the number of ground fault counters or power fault counters whose count value C exceeds the abnormality decision value Cd is one. If it is determined that there is no ground fault counter or power fault counter whose count value C exceeds the abnormality decision value Cd (S517: NO), the switching flag FlgB1 is not set, and the short-circuit location determination processing is terminated. If it is determined that the number of ground fault counters or power fault counters whose count value C exceeds the abnormality decision value Cd is one (S517: YES), the processing proceeds to S518.

[0153] In S518, the abnormality determination part 45 determines that a short-circuit abnormality has occurred at a location corresponding to the ground fault counter or the power fault counter whose count value C is greater than the abnormality decision value Cd. For example, when the count value C of the U-phase ground fault counter U1_g is greater than the abnormality decision value Cd, the U-phase of the first system 101 is determined to have a ground fault. More specifically, when the count value C of the U-phase ground fault counter U1_g is greater than the abnormality decision value Cd, the abnormality determination part 45 determines the short-circuit phase as the U-phase of the first system 101 and the short-circuit state as the ground fault. Further, when the count value C of the U-phase power fault counter U1_p is greater than the abnormality decision value Cd, the U-phase of the first system 101 is determined to have a power fault.Specifically, when the count value C of the U-phase power fault counter U1_p exceeds the abnormality decision value Cd, the abnormality determination part 45 determines the short-circuit phase as the U-phase of the first system 101 and the short-circuit state as the power fault. This also applies to the ground faults and the power faults of the other phases.

[0154] Further, the abnormality determination part 45 outputs information in accordance with the determined short-circuit location to the correction current calculation part 421. In addition, the abnormality determination part 45 outputs the switching flag FlgB1 to the switching part 422.

[0155] Here the Fig. 9A to 11B show simulation results for the case where the abnormality occurs in the first system 101 and the motor 80 rotates in the positive direction by the single-system control using the second system 201. In each of the Fig. 9A to 11B, the first electrical angle θ1 is understood as a horizontal axis. Fig. 9A, Fig. 10A and Fig. 11A show the first capacitor voltage Vc1 and the first terminal voltage average value Vt1, and the Fig. 9B, Fig. 10B and Fig. 11B shows the connection voltages Vu1, Vv1, Vw1 of the respective phases.

[0156] The Fig. 9A and Fig. 9B serve as examples for the case where an abnormality other than the short-circuit abnormality (such as an open-circuit fault) has occurred in the first system 101. When the abnormality that has occurred in the first system 101 is other than the short-circuit abnormality, the drive signals U1_H, U1_L, V1_H, V1_L, W1_H, W1_L are set to the OFF commands so that a current due to a back electromotive force generated by the rotation of the motor 80 does not flow on the first inverter 120 side.

[0157] Accordingly, as in Fig. 9A, the first terminal voltage average value Vt1 in the case where the short-circuit abnormality has not occurred in the first system 101 and the one-side driving is performed in the second system 201 does not deviate from the first electrical angle θ1, and the first terminal voltage average value Vt1 is in a range higher than the ground fault determination threshold value Vth_g and lower than the power fault determination threshold value Vth_p.

[0158] Further, in the present embodiment, when the abnormality in the first system 101 is different from the short-circuit abnormality and the one-system drive is performed in the second system 201, the torque compensation for compensating a corresponding amount of the torque ripple is not performed.

[0159] The Fig. 10A and Fig. 10B serve as examples for the case where the W-phase ground fault abnormality has occurred in the first system 101. As in Fig. As shown in FIG. 10A, when the W-phase ground fault abnormality has occurred in the first system 101, the terminal voltage average value Vt1 does not exceed the ground fault determination threshold value Vth_g in an angle range Rw_g including 120 ≤ θ1 ≤ 180, which corresponds to the W-phase ground fault determination range. Furthermore, the terminal voltage average value Vt1 exceeds the ground fault determination threshold value Vth_g in both the U-phase and V-phase ground fault determination ranges. Consequently, a phase in which the ground fault abnormality has occurred can be appropriately determined.

[0160] The Fig. 11A and Fig. 11B serve as examples for the case where the W-phase power fault abnormality has occurred in the first system 101. As in Fig. As shown in FIG. 11A, when the W-phase power fault abnormality has occurred in the first system 101, the terminal voltage average value Vt1 is not less than the power fault determination threshold value Vth_p in an angle range Rw_p including 300 ≤ θ1 ≤ 360, which corresponds to a W-phase power fault determination range. Furthermore, the terminal voltage average value Vt1 of both the U-phase and V-phase power fault determination ranges is less than the power fault determination threshold value Vth_p. Therefore, a phase in which the power fault abnormality has occurred can be appropriately determined.

[0161] While the example in which the W phase has a power fault or a ground fault is shown above, descriptions of the power faults and ground faults of the U phase and the V phase are omitted because they are the same as the power fault and ground fault of the W phase except for the difference in phase. Furthermore, when an abnormality occurs in the second system 201, the second electrical angle θ2 is used instead of the first electrical angle θ1, and the second terminal voltage average value Vt2 is used instead of the first terminal voltage average value Vt1, whereby a phase in which the ground fault abnormality or the power fault abnormality has occurred can be appropriately determined in a manner similar to the above.

[0162] As described above, the motor control device 1 of the present embodiment controls the motor 80 having the plurality of winding sets 810, 820. The winding sets 810, 820 each include the coils 811 to 813, 821 to 823 of the plurality of phases.

[0163] The motor control device 1 includes the inverters 120, 220, the power source relay parts 180, 280, the terminal voltage detection parts 140, 240 and the control part 40.

[0164] The inverters 120, 220 are provided for the respective winding sets 810, 820 and convert the energy of the motor 80.

[0165] The power source relay parts 180, 280 are provided corresponding to the respective inverters 120, 220 and can interrupt the power supply from the battery 5 to the inverters 120, 220. That is, the first power source relay part 180 can interrupt the power supply from the battery 5 to the first inverter 120, and the second power source relay part 280 can interrupt the power supply from the battery 5 to the second inverter 220.

[0166] The terminal voltage detection parts 140, 240 detect the terminal voltages Vu1, Vv1, Vw1, Vu2, Vv2, Vw2 of the coils 811 to 813, 821 to 823.

[0167] The control part 40 has the inverter control parts 41, 42, the relay control part 43 and the abnormality determination part 45.

[0168] The inverter control parts 41, 42 control the inverters 120, 220. Specifically, the first inverter control part 41 controls the ON / OFF operation of the SW elements 121 to 126 in the first inverter 120, and the second inverter control part 42 controls the ON / OFF operation of the SW elements 221 to 226 in the second inverter 220.

[0169] The relay control part 43 controls the power source relay parts 180, 280.

[0170] The abnormality determination part 45 determines an abnormality in the inverters 120, 220 and the winding sets 810, 820.

[0171] In the present embodiment, the combinations of the winding sets 810, 820 and the inverters 120, 220 that correspond to each other are referred to as "systems." That is, the combination of the first winding set 810 and the first inverter 120 is referred to as the first system 101, and the combination of the second winding set 820 and the second inverter 220 is referred to as the second system 201. Further, a system in which an abnormality has occurred is referred to as a faulty system, and a system operating normally is referred to as a normal system. Hereinafter, the description will be given assuming that the first system 101 is the faulty system and the second system 201 is the normal system.

[0172] When the motor 80 is operated using the second system 201, which is the normal system, the relay control part 43 controls the first power source relay part 180 to cut off the power supply from the battery 5 to the first inverter 120 in the first system 101, which is the faulty system.

[0173] Further, the abnormality determination part 45 determines a short-circuit location based on the terminal voltages Vu1, Vv1, Vw1 of the first system 101. Herein, “determines a short-circuit location” means that a short-circuit phase is determined and also determines whether the short-circuit phase has a ground fault or a power fault.

[0174] In accordance with the short-circuit location, the second inverter control part 42 corrects a command value related to control of the second inverter 220 in the second system 202, which is the normal system. In the present embodiment, the second inverter control part 42 corrects a q-axis current command value Iq2*.

[0175] In the present embodiment, in a state where the power supply from the battery 5 to the first inverter 120 is interrupted by the power source relay part 180 in the first system 101, which is the faulty system, a short-circuit location is determined based on the terminal voltages Vu1, Vv1, Vw1 generated by the counter electromotive force of the motor 80. Therefore, with the motor 80 in the rotating state, the short-circuit location can be appropriately determined.

[0176] Furthermore, the q-axis current command value Iq2* is corrected according to the short-circuit location to compensate for the torque generated by the current flowing during the short-circuit phase. Accordingly, the torque generated by the current flowing due to the counter electromotive force during the short-circuit phase is compensated, thereby enabling a reduction in torque ripple.

[0177] The terminal voltage detection parts 140, 240 detect the terminal voltages Vu1, Vv1, Vw1, Vu2, Vv2, Vw2 for the respective phases.

[0178] The abnormality determination part 45 determines a short-circuit location based on the terminal voltage average value Vt1, which is an average value of the terminal voltages Vu1, Vv1, Vw1 of the respective phases of the first system 101, which is the faulty system.

[0179] In this way, the short circuit location can be appropriately determined based on the terminal voltage of the faulty system.

[0180] The abnormality determination part 45 determines the short-circuit location after a predetermined waiting time has elapsed since the power supply from the battery 5 to the first inverter 120 in the first system 101, which is the faulty system, is interrupted. Thus, in particular, erroneous determination of the power failure abnormality can be prevented.

[0181] The abnormality determination part 45 determines the short-circuit location when the motor 80 is in a constant rotation state. When the motor 80 is not in a constant rotation state, the capacitor voltages Vc1, Vc2 may be unstable. Therefore, in the present embodiment, when the motor 80 is in the constant rotation state, it is assumed that the determinable condition is met, and the short-circuit location is then determined. Thus, the short-circuit phase and short-circuit state can be appropriately determined.

[0182] If multiple phases are determined to be short-circuit phases in the faulty system, correction of the command value according to the torque generated by a current flowing in the short-circuit phases is prevented. If multiple phases are determined to be short-circuit phases, the short circuit may not be caused by the power fault abnormality or the ground fault abnormality, but by an abnormality elsewhere. Accordingly, by prohibiting correction of the command value, an increase in torque ripple due to the correction can be prevented.

[0183] The electric power steering device 8 includes the motor control device 1 and the motor 80 that outputs an auxiliary torque to assist steering by the driver.

[0184] Since the motor 80 and the motor control device 1 of the present embodiment are constructed of multiple systems, even if an abnormality occurs in one system, the drive of the motor 80 can be continued by single-system drive using the normal system, thus continuing the steering assistance. Furthermore, the command value of the normal system is corrected in accordance with the short-circuit location, thus enabling a reduction in the torque ripple of the motor 80. Consequently, vibration and noise generated in the steering system 90 when the drive of the motor 80 continues using the normal system can be reduced.

[0185] Although the above mainly describes the case where the first system 101 is the faulty system, the same effect is achieved when the second system 201 is the faulty system. (Second embodiment)

[0186] A second embodiment of the present invention is described below with reference to the Fig. 12 to 15 described.

[0187] As in Fig. As shown in FIG. 12, a motor control device 2, which is a control device for a rotating electric machine of the present embodiment, includes inverters 120, 220, pseudo-neutral point generating parts 160, 260, pseudo-neutral point voltage detecting parts 165, 265, capacitors 170, 270, capacitor voltage detecting part 175, 275, power source relay part 180, 280, rotation angle sensor 30, control part 40, and the like. That is, the present embodiment differs from the above embodiment in that the pseudo-neutral point generating parts 160, 260 and the pseudo-neutral point voltage detecting parts 165, 265 are provided instead of the terminal voltage detecting parts 140, 240.

[0188] In the present embodiment, a first system 102 is constructed from the first winding set 810 and the electronic components provided corresponding to the first winding set 810, such as the first inverter 120, and a second system 202 is constructed from the second winding set 820 and the electronic components provided corresponding to the second winding set 820, such as the second inverter 220.

[0189] Hereinafter, similarly to the first embodiment, the configuration according to the first system 102 will be mainly described.

[0190] The pseudo-neutral point generating part 160 includes resistors 161, 162, and 163. One end of resistor 161 is connected to the U1 terminal 111, one end of resistor 162 is connected to the V1 terminal 112, and one end of resistor 163 is connected to the W1 terminal 113. The other ends of resistors 161, 162, and 163 are connected via a connecting part 164. The connecting part 164 is assumed to be a pseudo-neutral point. The connecting part 164 is connected to the first positive-side bus 116 via a step-up resistor 155.

[0191] The first pseudo-neutral point voltage detection part 165 includes resistors 166, 167 as partial resistors and is connected to the connecting part 164 and the first negative-side bus 117. A voltage of a node of the resistors 166, 167 is output to the control part 40 as a first pseudo-neutral point voltage detection value Vn1_d, which is a detection value corresponding to a first pseudo-neutral point voltage Vn1.

[0192] The resistance value of each of the resistors 161 to 163 constituting the first pseudo-neutral point generating part 160, the boost resistor 155, and the resistors 166, 167 constituting the first pseudo-neutral point voltage detecting part 165 can be determined as appropriate. In the present embodiment, the resistors 155, 161 to 163, 166 have the same resistance value, and the resistance ratio between the resistance value of each of the resistors 155, 161 to 163, 166 and that of the resistor 167 is 3:2.

[0193] The control part 40 converts the first pseudo neutral point voltage detection value Vn1_d based on the resistance value ratio of the resistors 166, 167 to calculate the first pseudo neutral point voltage Vn1.

[0194] That is, the pseudo-neutral point voltage Vn1 is described by equation (4-1). Furthermore, a second pseudo-neutral point voltage Vn2 is described by equation (4-2). Vn1=Vn1_d×{(3+2) / 2} Vn2=Vn2_d×{(3+2) / 2}

[0195] In fault location determination processing of the present embodiment, the pseudo neutral point voltages Vn1, Vn2 are used instead of the terminal average voltages Vt1, Vt2. Other aspects are the same as those of the above embodiment.

[0196] The Fig. 13 to 15 show simulation results for the case where the abnormality occurs in the first system 102 and the motor 80 rotates in the positive direction using the second system 202.

[0197] Fig. 13 serves as an example of the case where an abnormality other than the short-circuit abnormality (such as an open-circuit fault) has occurred in the first system 102. When the abnormality that has occurred in the first system 102 is other than the short-circuit abnormality, the drive signals U1_H, U1_L, V1_H, V1_L, W1_H, W1_L are set to the OFF commands so that a current due to a counter electromotive force generated by the rotation of the motor 80 does not flow on the first inverter 120 side. Accordingly, as shown in Fig. 13, the first pseudo neutral point voltage Vn1 in the case where the short-circuit abnormality has not occurred in the first system 102 and the one-system drive is performed in the second system 202 does not deviate from the first electrical angle θ1, and the first pseudo neutral point voltage Vn1 is in a range higher than the ground fault determination threshold value Vth_g and lower than the power fault determination threshold value Vth_p.

[0198] Further, similarly to the above embodiment, when the abnormality in the first system 102 is different from the short-circuit abnormality and the one-system drive is performed in the second system 202, the torque compensation for compensating a corresponding amount of the torque ripple is not performed.

[0199] Fig. 14 serves as an example of the case where the W-phase ground fault abnormality has occurred in the first system 102. As in Fig. As shown in Figure 14, when the W-phase ground fault abnormality has occurred in the first system 102, the pseudo neutral point voltage Vn1 does not exceed the ground fault determination threshold Vth_g in an angle range Rw_g including 120 ≤ θ1 ≤ 180, which corresponds to the W-phase ground fault determination range. Furthermore, the first pseudo neutral point voltage Vn1 of both the U-phase and V-phase ground fault determination ranges is above the ground fault determination threshold Vth_g. Therefore, a phase in which the ground fault abnormality has occurred can be appropriately determined.

[0200] Fig. 15 serves as an example of the case where the W-phase power fault abnormality has occurred in the first system 102. As in Fig.As shown in Figure 15, when the W-phase power fault abnormality has occurred in the first system 102, the pseudo neutral point voltage Vn1 is not less than the power fault determination threshold Vth_p in an angle range Rw_g including 300 ≤ θ1 ≤ 360, which corresponds to the W-phase ground fault determination range. Furthermore, the first pseudo neutral point voltage Vn1 of both the U-phase and V-phase power fault determination ranges is less than the power fault determination threshold Vth_p. Consequently, a phase in which the power fault abnormality has occurred can be appropriately determined.

[0201] While the example in which the W phase has a power fault or a ground fault is described above, the descriptions of the power faults and ground faults of the U phase and the V phase are omitted because they are the same as the power fault and ground fault of the W phase except for the difference in phase. Furthermore, when an abnormality occurs in the second system 202, the second electrical angle θ2 is used instead of the first electrical angle θ1, and the second pseudo-neutral point voltage Vn2 is used instead of the first pseudo-neutral point voltage Vn1, whereby a phase in which the ground fault abnormality or the power fault abnormality has occurred can be appropriately determined in a manner similar to the above.

[0202] The motor control device 2 further includes the pseudo neutral point generating parts 160, 260 provided for the respective winding sets 810, 820.

[0203] The first pseudo neutral point generating part 160 is a resistor group whose one end is connected to the terminals 111 to 113 of the coils 811 to 813 for the respective phases and whose other end is connected via the connecting part 164.

[0204] The second pseudo neutral point generating part 260 is a resistor group whose one end is connected to the terminals 211 to 213 of the coils 821 to 823 for the respective phases, and whose other end is connected via a connecting part 264.

[0205] The pseudo-neutral point voltage detecting parts 165, 265 detect, as the terminal voltages, the pseudo-neutral point voltages Vn1, Vn2, which are the voltages of the connecting parts 164, 264. That is, in the present embodiment, the pseudo-neutral point voltage detecting parts 165, 265 correspond to the "terminal voltage detecting parts."

[0206] Even with such a configuration, an effect similar to that of the above embodiment can be achieved. Furthermore, the number of resistors can be reduced compared to the case where the terminal voltage detection part is provided for each phase. (Other embodiments)(I) Command value

[0207] In the above embodiment, the command value corrected according to the short-circuit location is the q-axis current command value. In another embodiment, for example, a command value other than the q-axis current command value, such as a torque command value, may be corrected according to the short-circuit location. (II) Current detection part

[0208] In the above embodiments, the current detection element is the shunt resistor and is provided on the low-potential side of the lower-arm element. In another embodiment, the current detection element is not limited to the shunt resistor, but may be, for example, a Hall IC (IC = integrated circuit) or the like. Further, in another embodiment, the current detection element may be provided at a location other than the low-potential side of the SW element, on the low-potential side, such as the high-potential side of the upper-arm element, or at a location between the winding set and the inverter part. (III) Rotating electrical machine

[0209] In the above embodiments, two winding sets and, correspondingly, two inverter sections and the like are provided. In another embodiment, the number of winding sets and the number of inverters provided corresponding to the winding sets may be three or more. In this case, for example, if the first system is faulty, the command value can be corrected such that a torque ripple is compensated by the remaining two systems.

[0210] Furthermore, in the above embodiments, the first winding set and the second winding set are arranged such that each of their phases is shifted by 30 [°]. In another embodiment, any winding arrangement can be used. Furthermore, the ground fault detection range and the power fault abnormality range of each phase are determined in accordance with the winding arrangement and the electrical angle definition.

[0211] In the above embodiments, the rotating electric machine is a brushless three-phase motor. In another embodiment, the number of phases of the rotating electric machine is not limited to three, but may be four or more. Furthermore, the rotating electric machine is not limited to a brushless motor, but may be a motor of any design. Furthermore, the rotating electric machine is not limited to a motor, but may be a generator or a so-called motor-generator, which has a combined function of a motor and a generator.

[0212] In the above embodiments, the rotating electric machine is applied to the electric power steering device. In another embodiment, the rotating electric machine control device may be applied to a device other than the electric power steering device.

[0213] It is noted that a flowchart or the execution of the flowchart in the present application comprises sections (also referred to as steps), each denoted, for example, as S11. Furthermore, each section may be divided into multiple subsections, while multiple sections may be combined into a single section. Furthermore, each of the sections thus configured may also be referred to as a device, a module, or a means.

[0214] Although the present invention has been described above in connection with its embodiments, it should be understood that it is not limited to the embodiments and constructions. The present invention should be understood to include various modifications and equivalent arrangements. Furthermore, although various combinations and configurations are shown, other combinations and configurations including more, fewer, or only a single element are also to be understood as being within the scope of the present invention.

Claims

[1] A control device for a rotating electrical machine for controlling a rotating electrical machine (80) having a plurality of winding sets (810, 820) each having a plurality of coils (811 to 813, 821 to 823) corresponding to a plurality of phases, the control device for a rotating electrical machine comprising: - an inverter (120, 220) arranged for each winding set and converting energy of the rotating electrical machine; - a power source relay (180, 280) arranged for each inverter and interrupting a power supply from a power source (5) to the inverter; - a terminal voltage detector (140, 240, 165, 265) which detects a terminal voltage from each coil; and - a controller (40) comprising an inverter controller (41, 42) for controlling each inverter, a relay controller (43) for controlling each power source relay, and an abnormality determination unit (45) for determining an abnormality of each inverter and each winding set, wherein - a combination of each winding set and a corresponding inverter is defined as a system; - one of the systems in which an abnormality occurs is defined as a faulty system; - another of the systems operating normally is defined as a normal system; - when the rotating electrical machine is controlled using the normal system: - the relay controller controls the power source relay to interrupt the power supply from the power source to the inverter in the faulty system; - the abnormality determination unit determines a short-circuit location based on the terminal voltage in the faulty system; and - the inverter controller corrects a command value relating to the control of the inverter in the normal system in accordance with a specific short-circuit location; - the abnormality determination unit determines the short-circuit location after a predetermined waiting time has elapsed since the interruption of the power supply from the power source to the inverter in the faulty system; - the abnormality determination unit determines the short-circuit location when the rotating electrical machine is in a constant rotation state; and - the short-circuit location includes a short-circuited phase among the plurality of phases, and the short-circuited phase includes a phase in which a power fault abnormality or a ground fault abnormality occurs. [2] A control device for a rotating electric machine according to claim 1, further comprising: - a pseudo neutral point generator (160, 260) provided for each set of windings and forming a resistance group (161 to 163, 261 to 263) having one end connected to a terminal (111 to 113, 211 to 213) of each coil and having the other end connected via a connecting part (164, 264), wherein - the terminal voltage detector (165, 265) detects, as the terminal voltage, a pseudo neutral point voltage which is a voltage of the connecting part. [3] A control device for a rotating electric machine according to claim 1, wherein - the terminal voltage detector (140, 240) detects the terminal voltage for each phase; and - the abnormality determination unit determines the short-circuit location based on an average value of the terminal voltage of each phase in the faulty system. [4] A control device for a rotating electrical machine according to any one of claims 1 to 3, wherein the correction of the command value in accordance with the short-circuit location is prohibited when a plurality of phases are determined to be short-circuited in the faulty system. [5] Electric power steering device with: - the control device (1, 2) for a rotating electrical machine according to one of claims 1 to 4; and - the rotating electric machine that outputs auxiliary torque to support a driver's steering operation.

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