Rotary motor control system

Abstract

A rotating motor control system (100) controls an AC rotating motor (80) having M winding units (8). The rotating motor control system (100) comprises: M inverters (50) having multiple switching elements (5) and connected to a DC power supply (41) and each of the winding units (8) to convert power between DC and N-phase AC; M sets of current sensors (6), one set for each of the N-phase winding units (8), to detect the AC current flowing through each phase of each winding unit (8); and an inverter control device (30) that generates a switching control signal (S) to control the inverters (50) for controlling the multiple switching elements (5). The inverter control device (30) uses all the detection values ​​of the M sets of current sensors (6) in each of the N-phase phases to perform current feedback control of the rotating motor (80) and generates the switching control signal (S) shared by the M inverters (50).

Description

Technical Field

[0001] This invention relates to a rotary motor control system that uses an AC rotary motor with multiple winding units as the controlled object. Background Technology

[0002] Japanese Patent Application Publication No. 2018-130007 discloses a rotary electric machine control device (10) for controlling a rotary electric machine (80) having stator windings (180, 280) as multiple winding units (in the background art, the reference numerals in parentheses are reference numerals of the referenced document). This rotary electric machine control device (10) drives each of the stator windings (180, 280) of the two systems via independent inverters (120, 220). Furthermore, each inverter (120, 220) is subject to current feedback control via independent control units (131, 231). The feedback current is detected by independent current sensors (125, 225) relative to each stator winding (180, 280).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-130007 Summary of the Invention

[0006] In the aforementioned rotating electric machine control device (10), two inverters (120, 220) and two control units (131, 231) for controlling them respectively are required, thus easily increasing the cost of the device. On the other hand, when controlling the flow of current in the stator windings of the two systems to make the current of the same phase flow, as in the rotating electric machine control device (10), it is sometimes not necessary to independently provide all the drive devices (inverters and control circuits) for making the current flow in the two stator windings (180, 280) for each stator winding (180, 280). In rotating electric machines with multiple stator windings, the structure or electrical specifications of each stator winding are mostly the same. In such cases, for example, by controlling the two inverters corresponding to the two stator windings by a single control circuit, it is possible to achieve system miniaturization and cost reduction. For example, the two inverters can be controlled by outputting the same control signal from one control unit to the two inverters.

[0007] Thus, when multiple stator windings have identical structure or electrical specifications and the control circuit is a single system, current feedback control can be achieved by detecting the feedback current only on the AC side of any one inverter (or in one stator winding). However, even with identical specifications, the flowing current may not be exactly the same due to individual differences between the two stator windings or the two inverters. Therefore, when using only the current from any one inverter for current feedback control, the torque ripple and vibration of the rotating electric machine may increase.

[0008] In view of the above background, it is desirable to provide a technique for appropriately controlling a rotating electric motor in a system that controls an AC rotating electric motor having multiple winding units, thereby suppressing the increase in the size of the system as the number of winding units increases, and suppressing torque fluctuations, vibrations, etc.

[0009] In view of the above, a rotating electric motor control system is provided in one manner, which controls an AC rotating electric motor having M (M is a natural number greater than 2) N-phase (N is a natural number) winding units. The rotating electric motor control system comprises: M inverters having multiple switching elements and connected to a DC power supply and each of the winding units to convert power between DC and N-phase AC; M sets of current sensors, one set for each of the N-phase winding units, to detect the AC current flowing through each phase of each winding unit; and an inverter control device that generates switching control signals to control the multiple switching elements to control the inverters. The inverter control device uses all the detection values ​​of the M sets of current sensors in each of the N-phase phases to perform current feedback control of the rotating electric motor and generates the switching control signals shared by the M inverters.

[0010] According to this structure, all M inverters are controlled by the same switching control signal. Therefore, even if the rotating electric machine has multiple winding units, the size of the rotating electric machine control system can be suppressed from increasing with the number of winding units. Furthermore, the inverter control device controlling the M inverters uses all detected values ​​of the current flowing through all M winding units for current feedback control. For example, even if all M winding units and all M inverters have the same structure or electrical specifications, there may be differences in electrical characteristics due to individual variations. By using the detected values ​​of all M sets of current sensors for current feedback control, the inverter control device can suppress control errors caused by such individual differences. Thus, according to this structure, in a system controlling an AC rotating electric machine with multiple winding units, the size of the system can be suppressed from increasing with the number of winding units, and torque fluctuations or vibrations can be suppressed, thereby enabling proper control of the rotating electric machine.

[0011] Other features and advantages of the rotating electric motor control system will become clear from the following description of the embodiments illustrated in the accompanying drawings. Attached Figure Description

[0012] Figure 1 This is a block diagram illustrating an example of a rotating electric motor control system.

[0013] Figure 2 This is a block diagram illustrating an example of an inverter control device.

[0014] Figure 3 This is an explanatory diagram illustrating the relationship between the dq-axis orthogonal vector coordinate system and the three-phase coordinate system.

[0015] Figure 4 This is a block diagram representing other examples of inverter control devices. Detailed Implementation

[0016] Hereinafter, an embodiment of the rotary electric motor control system will be described based on the accompanying drawings. The rotary electric motor control system, for example, performs drive control on a rotary electric motor that serves as a driving force source for a vehicle. Figure 1 The block diagram schematically illustrates the system structure of the rotating electric motor control system 100. The rotating electric motor control system 100 controls an AC rotating electric motor 80 having M (M is a natural number greater than 2) N-phase (N is a natural number) winding units 8. All M winding units 8 are of the same specification (same structure and same electrical specifications); in this embodiment, all are 3-phase (N=3) winding units 8. Furthermore, in this embodiment, an example is shown where the rotating electric motor 80 has two winding units 8 (M=2): a first winding unit 81 and a second winding unit 82.

[0017] The rotating motor control system 100 drives a rotating motor 80, which is a permanent magnet synchronous motor (PMSM). This permanent magnet synchronous motor has a stator 8s with two winding units 8 arranged in the stator core (see reference). Figure 3 ), and a rotor 8r with a permanent magnet 8m disposed in the rotor core (see reference). Figure 3 In this embodiment, such as Figure 1 As shown, a winding unit 8 with a star connection (Y connection) and a three-phase stator winding (8u, 8v, 8w) short-circuited at the neutral point NP is illustrated. However, the number of phases, the wiring method (star connection or delta connection), and the winding method of the stator windings (8u, 8v, 8w) (distributed winding or concentrated winding) are not limited. Furthermore, the rotating electrical machine 80 can function as either a motor or a generator.

[0018] The rotating electric motor control system 100 has M inverters 50, which are connected to a DC power supply 41 and various winding units 8 to convert power between DC and N-phase AC. In this embodiment, as... Figure 1 As shown, the rotating electric machine control system 100 includes: a first inverter 51 connected to a DC power supply 41 and a first winding unit 81 to convert power between DC and N-phase (here, 3-phase) AC; and a second inverter 52 connected to a DC power supply 41 and a second winding unit 82 to convert power between DC and N-phase (here, 3-phase) AC. That is, the rotating electric machine control system 100 has two inverters 50 corresponding to the two winding units 8. The first inverter 51 and the second inverter 52 are inverters of the same specifications (same structure and same electrical specifications).

[0019] The DC power supply 41 is composed, for example, of a rechargeable secondary battery (battery) such as a lithium-ion battery, or a double-layer capacitor. When the rotary motor 80 is the driving force source for the vehicle, the DC power supply 41 is a high-voltage, high-capacity DC power supply, with a rated power supply voltage of, for example, 200–400 V. The inverter 50 has a smoothing capacitor (DC link capacitor 42) on its DC side to smooth the voltage between the positive and negative terminals (DC link voltage).

[0020] Each inverter 50 is configured to have multiple switching elements 5. The switching elements 5 preferably employ power semiconductor devices such as IGBTs (Insulated Gate Bipolar Transistors), power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), SiC-MOSFETs (Silicon Carbide-Metal Oxide Semiconductor FETs), SiC-SITs (SiC-Static Induction Transistors), and GaN-MOSFETs (Gallium Nitride MOSFETs). Figure 1 The example illustrates the use of an IGBT as a switching element 5. Furthermore, each switching element 5 includes a freewheeling diode 5d connected in parallel in the positive direction (from the negative terminal to the positive terminal, or from the lower stage side to the upper stage side).

[0021] Each inverter 50 has multiple sets (in this case, three sets) of AC one-phase arms consisting of series circuits of upper-side switching elements 5H and lower-side switching elements 5L. In this embodiment, a bridging circuit corresponding to one set of series circuits (arms) is constructed in each of the stator windings (8u, 8v, 8w) corresponding to the U-phase, V-phase, and W-phase of each winding unit 8. The midpoint of the arm, i.e., the connection point between the upper-side switching element 5H and the lower-side switching element 5L, is respectively connected to the stator windings (8u, 8v, 8w) corresponding to the U-phase, V-phase, and W-phase of each winding unit 8.

[0022] like Figure 1 As shown, each inverter 50 is controlled by an inverter control unit 30. The inverter control unit 30 includes a control circuit 10 (CTRL) and a drive circuit 20 (DRV). Figure 1 (as well as Figure 2The diagram illustrates a configuration where two (M) inverters 50 each have two (M) drive circuits 20. Specifically, a first drive circuit 21 corresponds to the first inverter 51, and a second drive circuit 22 corresponds to the second inverter 52. All drive circuits 20 are identical in specifications (same structure and same electrical specifications), and both the first drive circuit 21 and the second drive circuit 22 are identical in specifications (same structure and same electrical specifications). Although described in detail later, the control circuit 10 is shared by both inverters 50, generating switching control signals S (source signals SS) for controlling the multiple switching elements 5 of the first inverter 51 and the second inverter 52. In other words, the control circuit 10 generates switching control signals S (source signals SS) for the inverters 50 to control all M inverters 50.

[0023] The control circuit 10 is constructed with a processor, such as a microcomputer, as its core component. For example, the control circuit 10 is based on the target torque (torque command T*: see reference) of the rotary motor 80 provided as a request signal from other control devices, such as a vehicle control device (not shown) that is one of the higher-level control devices. Figure 2 (etc.), current feedback control using vector control is performed, and the rotating motor 80 is controlled via inverter 50. For example... Figure 3 As shown, in vector control, the coordinates of the actual current (In: Iu, Iv, Iw) flowing in the rotating electric machine are converted into vector components (Id, Iq) of the direction of the magnetic field (magnetic flux) generated by the permanent magnet 8m positioned on the rotor 8r, i.e., the d-axis, and the direction orthogonal to the d-axis (the direction of travel relative to the direction of the magnetic field at an electrical angle π / 2), for feedback control. Additionally, "Ia" represents the synthesized current after vector synthesis. (Refer to...) Figure 2 As will be described later, the inverter control device 30 (control circuit 10) performs feedback control on the rotating motor 80 in the dq axis orthogonal vector coordinate system based on the deviation between the current command (I*) based on the torque command T* of the rotating motor 80 and the actual current In.

[0024] like Figure 1 as well as Figure 2 As shown, the actual current In flowing in the rotating motor 80 is detected by two (M sets) current sensors 6 (SEN-I), and the control circuit 10 acquires the detection result. One set of current sensors 6 is provided relative to an N-phase winding unit 8 to detect the alternating current flowing through each phase of each winding unit 8. In this embodiment, as... Figure 1 As shown, two sets of current sensors 6 (61, 62) are provided relative to the two winding units 8 (81, 82).

[0025] The actual current In flows in the first winding unit 81 and the second winding unit 82 (all M winding units 8). To detect the current flowing through all M winding units 8, M sets of current sensors 6 are provided. In this embodiment, it includes: a first current sensor 61, which detects the alternating current flowing through each phase of the first winding unit 81; and a second current sensor 62, which detects the alternating current flowing through each phase of the second winding unit 82. Although in Figure 1 The example illustrates how the current sensor 6 detects the AC current of three phases. However, in the case of three-phase AC, the three phases are balanced and their instantaneous values ​​sum to zero. Therefore, only the current of two phases can be detected, and the remaining phase can be obtained by the control circuit 10 through calculation. That is, each current sensor 6 (61, 62) does not necessarily have to have N detection units corresponding to all N; it can also be configured to have (N-1) detection units. The current value obtained through calculation can also be considered as the detected value. Therefore, even in this case, the inverter control device 30 uses all the detected values ​​of the current of each of the N phases to provide current feedback to the rotating motor 80.

[0026] In addition, the magnetic pole positions (electrical angle θ: reference) of the rotor 8r of the rotary electric machine 80 at various time points. Figure 3 The rotational speed (angular velocity ω) of the rotor 8r is detected, for example, by a rotation sensor 7 (SEN-R) such as a rotary transformer, and the control circuit 10 acquires this detection result. The control circuit 10 uses the detection results of the current sensor 6 and the rotation sensor 7 to perform current feedback control.

[0027] like Figure 2 As shown, the control circuit 10 is configured to have various functional units for performing current feedback control, and each functional unit is implemented through the cooperation of hardware and software (programs) such as a microcomputer. In this embodiment, the control circuit 10 includes: a current command calculation unit 11, a voltage command calculation unit 12, a 2-phase to 3-phase coordinate conversion unit 13, a modulation unit 14, a 3-phase to 2-phase coordinate conversion unit 15, and an actual current calculation unit 16. The inverter control device 30 (control circuit 10) converts the N-phase AC current, i.e. the actual current In, into a 2-phase current Idq (Id, Iq) in the dq-axis orthogonal vector coordinate system. Based on the deviation between the current command in the dq-axis orthogonal vector coordinate system, i.e., the 2-phase current command I* (Id*, Iq*), and the 2-phase current Idq (Id, Iq), it calculates the 2-phase voltage command V* (Vd*, Vq*) in the dq-axis orthogonal vector coordinate system. The 2-phase voltage command V* (Vd*, Vq*) is then converted into an N-phase voltage command (here, a 3-phase voltage command Vn* (Vu*, Vv*, Vw*)) applied to the first winding unit 81 and the second winding unit 82 of the N-phase. Based on the N-phase voltage command (Vn*: Vu*, Vv*, Vw*), a switching control signal S (source signal SS) is generated.

[0028] The current command calculation unit 11 calculates the target current (2-phase current command I*) flowing in the rotary motor 80 based on the torque command T* (target torque). As described above, since the control circuit 10 performs feedback control on the rotary motor 80 in the dq-axis orthogonal vector coordinate system, the current command calculation unit 11 calculates the d-axis current command Id* and the q-axis current command Iq* as the current command I*. Here, the current command calculation unit 11 can "calculate the 2-phase current command I* using the current flowing in one winding unit 8 as the target current," or it can "calculate the 2-phase current command I* using the current obtained by summing the current flowing in the first winding unit 81 and the current flowing in the second winding unit 82 (the current obtained by summing the currents flowing in all M winding units 8) as the target current." When the current command calculation unit 11 "calculates the 2-phase current command I* using the current flowing in one winding unit 8 as the target current," the torque command T* is half of the overall target torque of the rotary motor 80. Then, in this case, the torque command T* is the same for each winding unit 8, and the two-phase current command I* for each winding unit 8 is also the same.

[0029] The voltage command calculation unit 12 calculates the two-phase voltage command V*, which is the command to apply voltage to the inverter 50, based on the deviation between the two-phase current command I* and the actual current In of the rotating motor 80 (U-phase current Iu, V-phase current Iv, W-phase current Iw). Although the voltage command calculation unit 12 is illustrated here as having a proportional-integral (PI) controller, it can also be configured as having a proportional-derivative-integral (PID) controller.

[0030] In this embodiment, the inverter control device 30 (control circuit 10) uses the detection values ​​of the first current sensor 61 (i.e., the first detection value I1) in each of the N-phase (3-phase) phases and the detection values ​​of the second current sensor 62 (i.e., the second detection value I2) in each of the N-phase (3-phase) phases to perform current feedback control of the rotating motor 80. Therefore, as Figure 2 As shown, the control circuit 10 has an actual current calculation unit 16, which calculates the actual current In flowing in the rotary motor 80 based on the first detection value 11 and the second detection value 12.

[0031] When the current command calculation unit 11 calculates the two-phase current command I* by taking the current flowing in a winding unit 8 as the target current, as shown in the following mathematical formulas (1) to (3), the actual current calculation unit 16 calculates the actual current In flowing in the rotary motor 80 by averaging the first detection value I1 and the second detection value I2 (the following mathematical formulas illustrate the case of "M=2").

[0032] Iu=(Iu1+Iu2) / 2…(1)

[0033] Iv=(Iv1+Iv2) / 2…(2)

[0034] Iw=(Iw1+Iw2) / 2…(3)

[0035] The actual current calculation unit 16 is configured to have an adder that adds the first detection value I1 and the second detection value I2 at the same time, and divides the result by 2 to calculate the actual current In. In the control circuit 10, which uses a microcomputer as its core, the calculation is performed using binary numbers. Therefore, as in this embodiment, when "M=2", by bit shifting the addition result (in this case, right shift), it is easy to divide by 2 to obtain the average value (including rounding up, down, and rounding of the mantissa). When the current command calculation unit 11 calculates the two-phase current command I* using the current flowing in one winding unit 8 as the target current, the deviation calculation unit 12a calculates the deviation between the two-phase current command I* and the actual current In obtained by averaging the current values ​​of each winding unit 8 in the actual current calculation unit 16. Figure 2 As shown, the deviation calculation unit 12a is configured to have an adder (subtractor).

[0036] When the current command calculation unit 11 calculates the two-phase current command I* by summing the current flowing in the first winding unit 81 and the current flowing in the second winding unit 82 (the current obtained by summing the current flowing in all M winding units 8) as the target current, the actual current calculation unit 16 calculates the actual current In flowing in the rotary motor 80 by summing the first detection value I1 and the second detection value I2. The actual current calculation unit 16 is configured to have an adder, which calculates the actual current In by adding the first detection value I1 and the second detection value I2 at the same time. In this case, the two-phase current command I* is calculated by summing the current flowing in the first winding unit 81 and the current flowing in the second winding unit 82 as the target current, and the deviation calculation unit 12a calculates the deviation between the two-phase current command I* and the actual current In after summing in the actual current calculation unit 16.

[0037] In the above example, although the case of "M=2" was illustrated, the actual current calculation unit 16 calculates the actual current In flowing in the rotary motor 80 by averaging the detection values ​​of the M current sensors 6 (by adding all the detection values ​​of the M sets of current sensors 6 and dividing by M). Alternatively, the actual current calculation unit 16 calculates the actual current In flowing in the rotary motor 80 by adding all the detection values ​​of the M sets of current sensors 6 corresponding to the M winding units 8.

[0038] Since the deviation between the actual current In (Iu, Iv, Iw) and the two-phase current command I* is calculated in the deviation calculation unit 12a, the actual current In (Iu, Iv, Iw) is coordinate transformed in the three-phase / two-phase coordinate transformation unit 15 (for the concept of coordinate transformation, refer to...). Figure 3 The current is Idq (Id, Iq) for two phases. The three-phase to two-phase coordinate transformation unit 15 performs coordinate transformation based on the rotational position (magnetic pole position, electrical angle θ) of the rotor 8r at each time point detected by the rotation sensor 7 (SEN-R).

[0039] exist Figure 2 The example illustrates how the deviation between the two-phase current Idq (d-axis current Id, q-axis current Iq) converted by the 3-phase to 2-phase coordinate transformation unit 15 and the d-axis current command Id* and q-axis current command Iq* is calculated in the deviation calculation unit 12a between the current command calculation unit 11 and the voltage command calculation unit 12. However, the deviation calculation unit 12a may also be included in the voltage command calculation unit 12, thereby performing the deviation calculation by the voltage command calculation unit 12. The voltage command calculation unit 12 calculates the d-axis voltage command Vd* based on the deviation between the d-axis current command Id* and the d-axis current Id and the rotational speed (angular velocity ω), and calculates the q-axis voltage command Vq* based on the deviation between the q-axis current command Iq* and the q-axis current Iq and the rotational speed (angular velocity ω).

[0040] The 2-phase / 3-phase coordinate transformation unit 13 converts the 2-phase voltage command V* (d-axis voltage command Vd*, q-axis voltage command Vq*) coordinates in the dq-axis orthogonal vector coordinate system into 3-phase voltage commands Vn* (U-phase voltage command Vu*, V-phase voltage command Vv*, W-phase voltage command Vw*) corresponding to the 3-phase inverter 50. The modulation unit 14 generates the 3-phase switching control signal S (source signal SS) of the inverter 50 based on each of the 3-phase voltage commands Vn* (U-phase voltage command Vu*, V-phase voltage command Vv*, W-phase voltage command Vw*). Figure 2As shown, since a switching control signal S (source signal SS) controlling the upper-side switching element 5H and the lower-side switching element 5L is generated in each of the U-phase, V-phase, and W-phase, a total of six switching control signals S (source signals SS) are generated. Here, the method by which the modulation unit 14 generates the switching control signals by controlling pulse width modulation (PWM) is illustrated.

[0041] The control terminals (e.g., the gate terminals of IGBTs) of each switching element 5 constituting the inverter 50 are connected to the control circuit 10 via the drive circuit 20, and each switching element 5 is independently controlled for switching. As described above, the control circuit 10, which generates the source signal SS for the switching control signal S, is configured with a microcomputer or similar core, and its operating voltage is, for example, 5V, 3.3V, 2.5V, etc. On the other hand, as described above, the inverter 50 is connected to a DC power supply 41 with a rated power supply voltage of, for example, 200 to 400V, and requires a drive signal of, for example, 15 to 20V to be input to the control terminals of the switching elements 5.

[0042] The drive circuit 20 enhances the driving capability (e.g., voltage amplitude, output current, etc., enabling the subsequent circuits to operate) of the source signal SS of the switching control signal S generated by the control circuit 10, and relays it to the inverter 50. The signal output from the drive circuit 20, distinguished from the source signal SS generated by the control circuit 10, is called the drive signal DS. Furthermore, the source signal SS and the drive signal DS are collectively referred to as the switching control signal S. In other words, the inverter control device 30 is a device that generates the switching control signal S, or generates and outputs the switching control signal S; more specifically, it is a device that generates the source signal SS and outputs it as the drive signal DS.

[0043] As described above, the first winding unit 81 and the second winding unit 82 (all M winding units 8) have the same structure and identical electrical specifications, except for individual differences. Similarly, the first inverter 51 and the second inverter 52 (all M inverters 50) also have the same structure and identical electrical specifications, except for individual differences. Furthermore, in this embodiment, the two inverters 50 are switched on and off at the same time. Therefore, the two inverters 50 (all M inverters 50) are switched on and off using a shared switching control signal S (drive signal DS). Thus, the inverter control device 30 generates a shared switching control signal S (source signal SS, drive signal DS) for the first inverter 51 and the second inverter 52 (all M inverters 50).

[0044] like Figure 1 as well as Figure 2As shown, in this embodiment, the control circuit 10 generates a source signal SS shared by the first inverter 51 and the second inverter 52 (all M inverters 50), and provides each inverter 50 with a drive signal DS relayed by different drive circuits 20 based on the same source signal SS. That is, the drive signal DS relayed by the first drive circuit 21 based on the same source signal SS is provided to the first inverter 51, and the drive signal DS relayed by the second drive circuit 22 based on the same source signal SS is provided to the second inverter 52. In this manner, in the two inverters 50 (all M inverters 50), the control terminals (in this case, the gate terminals) of the switching elements 5 that perform switching control at the same time (e.g., the upper-side switching elements 5H of the U phase, etc.) are separated by clamping the respective drive circuits 20, thus suppressing the situation where they interfere with each other due to individual differences.

[0045] However, this approach is not limited to, for example, situations where the influence between the switching elements 5 can be ignored. Figure 4 As shown, the drive signal DS output from the same drive circuit 20 can also be provided to different inverters 50. In this case, since the number of drive circuits 20 can be reduced, the rotary motor control system 100 can be miniaturized and its cost reduced.

[0046] Thus, since the winding units 8 have the same structure or electrical specifications, and the inverters 50 have the same structure or electrical specifications, they can be controlled by a single control circuit 10 (an inverter control device 30), and thus, as in this embodiment, multiple sets of current sensors 6 are not required. For example, in the case of "M=2", by detecting the AC current only in the AC side (one winding unit 8) of any one inverter 50 and performing feedback control, both inverters 50 can be driven by the same switching control signal S (source signal SS). Regarding the other inverter 50 (another winding unit 8), for example, an overcurrent detection circuit using a shunt resistor can be provided, so that the overcurrent detection circuit can also be used in case of a fault. In the case of M=3 or more, by detecting the AC current only in any number of winding units 8 up to (M-1) and performing feedback control, all M inverters 50 can be driven using the same switching control signal S (source signal SS). Regarding the inverter 50 (winding unit 8) that does not detect AC current, it is sufficient to have an overcurrent detection circuit using a shunt resistor, as described above.

[0047] However, even with identical specifications, individual differences in the winding units 8 or the switching elements 5 constituting the inverter 50 can lead to differences in the AC current flowing in the first winding unit 81 and the AC current flowing in the second winding unit 82. That is, there may be deviations in the AC current flowing in each of the M winding units 8. Therefore, when feedback control is applied to the current flowing in two winding units 8 based on the current flowing in any one winding unit 8, the difference in current flowing in the two winding units 8 may increase due to errors. In other words, when feedback control is applied to the current flowing in all M winding units 8 based on the current flowing in a subset of the M winding units 8, the difference in current flowing in each winding unit 8 may increase due to errors. Specifically, the difference between the current corresponding to the torque command T* (target torque) and the actual current flowing in the rotating motor 80 may increase. This current difference then causes variations in the torque of the rotating motor 80.

[0048] However, as described above, by using feedback control based on the average or sum of the detected values ​​of the current flowing through the first winding unit 81 (i.e., the first detected value I1) and the detected values ​​of the current flowing through the second winding unit 82 (i.e., the second detected value I2), the current corresponding to the torque command T* (target torque) can flow through the rotary motor 80. That is, by using feedback control through the average or sum of the detected values ​​of the M sets of current sensors 6 in each of the N phases, the current corresponding to the torque command T* (target torque) can flow through the rotary motor 80. Therefore, the rotary motor 80 can output the torque corresponding to the torque command T*, thereby suppressing torque fluctuations.

[0049] Of course, feedback control can also be performed on the first system of the first winding unit 81 and the first inverter 51, and the second system of the second winding unit 82 and the second inverter 52, respectively, through different control loops. That is, feedback control can also be performed based on M systems through M control loops. However, in this case, multiple... Figure 1 as well as Figure 2 The control circuit 10 is as illustrated. Alternatively, if a time-sharing operation is required for a control circuit 10, the computational load on the processor, such as a microcomputer, which is the core of the control circuit 10, increases, and a processor with high computing power may be needed depending on the situation. Therefore, the size and cost of the rotary electric motor control system 100 may increase.

[0050] As described above, in this embodiment, the winding units 8 of two systems and the inverter 50 can be controlled by a single control circuit 10. That is, the winding units 8 of multiple systems (M in total) and the inverter 50 can be controlled by a single control circuit 10. Therefore, the increase in the size and cost of the rotating electric motor control system 100 can be suppressed. Thus, according to this embodiment, in the rotating electric motor control system 100 that controls an AC rotating electric motor 80 having multiple winding units 8, the increase in the size of the system as the number of winding units 8 increases can be suppressed, and torque fluctuations or vibrations can be suppressed, thereby enabling appropriate control of the rotating electric motor 80.

[0051] The above example illustrates a rotary motor control system 100 that controls an AC rotary motor 80 having an N-phase (N is a natural number) first winding unit 81 and an N-phase second winding unit 82. Specifically, the rotary motor control system 100 includes: a first inverter 51 connected to a DC power supply 41 and the first winding unit 81 to convert power between DC and N-phase AC; a second inverter 52 connected to the DC power supply 41 and the second winding unit 82 to convert power between DC and N-phase AC; a first current sensor 61, provided in a set for each N-phase winding unit 8, to detect the AC current flowing through each phase of the first winding unit 81; and a second current sensor 62, provided in a set for each N-phase winding unit 8, to detect the AC current flowing through the second winding unit 81. The inverter control device 30 generates switching control signals S for the first inverter 51 and the second inverter 52 to control the first inverter 51 and the second inverter 52. An example is given whereby the inverter control device 30 uses the detection values ​​(first detection value I1) of the first current sensor 61 in each of the N phases and the detection values ​​(second detection values ​​I2) of the second current sensor 62 in each of the N phases to perform current feedback control on the rotating motor 80, thereby generating a switching control signal S shared by the first inverter 51 and the second inverter 52. Although the case of "M=2" is illustrated here, as appropriately illustrated, those skilled in the art can easily understand even when M is 3 or more, therefore detailed explanation is omitted.

[0052] (Summary of the implementation method)

[0053] The following is a brief overview of the rotary electric motor control system (100) described above.

[0054] A rotating electric motor control system (100) controls an AC rotating electric motor (80) having M (M is a natural number greater than 2) N-phase (N is a natural number) winding units (8). The rotating electric motor control system (100) includes: M inverters (50) having multiple switching elements (5) connected to a DC power supply (41) and each of the winding units (8) to convert power between DC and N-phase AC; and M sets of current sensors (6) corresponding to one of the N-phase windings. Unit (8) is provided with one set to detect the AC current flowing through each phase of each winding unit (8); and inverter control device (30) to generate a switching control signal (S) for controlling multiple switching elements (5) to control the inverter (50). The inverter control device (30) uses all the detection values ​​of the current sensors (6) in each of the N phases of the M sets to perform current feedback control of the rotating motor (80) and generate the switching control signal (S) shared by the M inverters (50).

[0055] According to this structure, all M inverters (50) are controlled by the same switching control signal (S). Therefore, even if the rotating motor (80) has multiple winding units (8), the size of the rotating motor control system (100) can be suppressed from increasing with the number of winding units (8). In addition, the inverter control device (30) controlling the M inverters (50) performs current feedback control using all the detected values ​​of the current flowing through the M winding units (8). For example, even if all M winding units (8) and all M inverters (50) have the same structure and electrical specifications, there may be differences in electrical characteristics due to individual differences. The inverter control device (30) performs current feedback control by using the detected values ​​of all M sets of current sensors (6), which can suppress control errors caused by such individual differences. According to this structure, in a system (100) that controls an AC rotating motor (80) having multiple winding units (8), it is possible to suppress the increase in the size of the system (100) as the number of winding units (8) increases, and to suppress torque fluctuations or vibrations, thereby enabling proper control of the rotating motor (80).

[0056] Preferably, the inverter control device (30) averages the detection values ​​of the M sets of current sensors (6) to calculate the actual current (In) flowing in the rotating motor (80), or adds up all the detection values ​​of the M sets of current sensors (6) to calculate the actual current flowing in the rotating motor (80), and performs current feedback control of the rotating motor (80).

[0057] The switching control signal (S) generated and output by the inverter control device (30) corresponds to an inverter (50) and a winding unit (8). Therefore, the current flowing through the winding unit (8) via the inverter (50) is approximately (1 / M) of the current flowing in the rotating motor (80). Thus, by averaging the detection values ​​of the M sets of current sensors (6) to obtain the actual current (In), current feedback control is performed, thereby enabling proper control of the rotating motor (80). Furthermore, the sum of the detection values ​​of the M sets of current sensors (6) represents the current flowing in the rotating motor (80), which outputs torque based on this current. Therefore, by summing all the detection values ​​of the M sets of current sensors (6) to obtain the actual current (In), current feedback is performed, thereby enabling proper control of the rotating motor (80).

[0058] Preferably, in a vector coordinate system where the direction of the magnetic flux of the permanent magnet (8m) of the rotor (8r) of the rotating motor (80) is the d-axis and the q-axis is orthogonal to the d-axis, the inverter control device (30) performs feedback control on the rotating motor (80) based on the deviation between the current command (I*) based on the target torque (T*) of the rotating motor (80) and the actual current (In). The inverter control device (30) converts the N-phase AC current, i.e., the actual current (In), into the dq-axis... The two-phase current (Idq) in the orthogonal vector coordinate system is calculated based on the deviation between the current command (I*) in the dq-axis orthogonal vector coordinate system, i.e., the two-phase current command (I*) and the two-phase current (Idq). The two-phase voltage command (V*) in the dq-axis orthogonal vector coordinate system is converted into an N-phase voltage command (Vn*) applied to the first winding unit (81) and the second winding unit (82) of the N phase. The switch control signal (S) is generated based on the N-phase voltage command (Vn*).

[0059] Based on such vector control, an N-phase AC rotating motor (80) rotating in an N-dimensional (N-phase) coordinate system can be controlled in the same 2-dimensional (2-phase) coordinate system as a DC rotating motor. Therefore, feedback control can be appropriately performed on the rotating motor (80) having multiple winding units (8).

[0060] In addition, preferably, the inverter control device (30) has a rotation sensor (7). When the rotating motor (80) is subjected to feedback control in the dq-axis orthogonal vector coordinate system, the rotation sensor (7) detects the rotation of the rotor (8r). The inverter control device (30) performs coordinate transformation between the N-phase coordinate system and the dq-axis orthogonal vector coordinate system based on the rotation position (θ) of the rotor (8r) detected by the rotation sensor (7).

[0061] In vector control, the dq-axis orthogonal vector coordinate system is a rotating coordinate system in which the stator (8s) rotates relative to the fixed coordinate system. Preferably, the dq-axis orthogonal vector coordinate system rotates according to the rotation of the rotor (8r), and therefore, coordinate transformation is performed based on the rotational position (θ) of the rotor (8r) detected by the rotation sensor (7).

[0062] Preferably, each of the winding units (8) is a three-phase winding with the windings (8u, 8v, 8w) of each phase connected in a star configuration at the neutral point (NP).

[0063] The inverter (50), which is connected to both the DC power supply (41) and the AC rotating motor (80), is, in most cases, a voltage-controlled type due to its ease of control. Therefore, preferably, the winding unit (8) of the rotating motor (80) connected to the inverter (50) is also, for example, in the case of 3-phase AC, where the line-to-line voltage is 3 times the phase voltage. (1 / 2) A star connection with a voltage of √3 times.

[0064] Explanation of reference numerals in the attached figures:

[0065] 5: Switching elements

[0066] 6: Current sensor

[0067] 7: Rotation sensor

[0068] 8: Winding Unit

[0069] 8m: Permanent magnet

[0070] 8r: Rotor

[0071] 8u: U-phase winding (windings for each phase)

[0072] 8V: V-phase windings (windings for each phase)

[0073] 8w: W-phase winding (windings for each phase)

[0074] 30: Inverter control device

[0075] 41: DC power supply

[0076] 50: Inverter

[0077] 80: Rotary motor

[0078] 81: First winding unit

[0079] 100: Rotary Electric Machine Control System

[0080] I*: 2-phase current command

[0081] I1: First detection value

[0082] I2: Second detection value

[0083] In: Actual current

[0084] NP: Neutral point

[0085] S: Switch control signal

[0086] T*: Torque command (target torque)

[0087] V*: 2-phase voltage command

[0088] Vn*: 3-phase voltage command (N-phase voltage command)

[0089] θ: Electrical angle (rotor rotational position)

Claims

1. A control system for a rotating electric machine, wherein an AC rotating electric machine having M winding units (M being a natural number greater than 2) and N phases (N being a natural number) is used as the controlled object, wherein, The rotary motor control system has the following features: M inverters, each having multiple switching elements, are connected to a DC power supply and each of the winding units to convert power between DC and N-phase AC. M sets of current sensors are provided for each of the N-phase winding units to detect the alternating current flowing through each phase of each winding unit. as well as An inverter control device generates switching control signals to control the inverter by controlling the plurality of said switching elements. The inverter control device uses all the detection values ​​of the M sets of current sensors in each of the N phases to perform current feedback control of the rotating motor, generating M switching control signals shared by the inverters. The inverter control device averages the detection values ​​of the M sets of current sensors at the same time to calculate the actual current flowing in the rotating motor. Based on the deviation between the actual current and the target current flowing in one of the winding units, it performs current feedback control of the rotating motor, or... The inverter control device adds the detection values ​​of the M sets of current sensors at the same time to calculate the actual current flowing in the rotating motor. Based on the deviation between the actual current and the target current obtained by summing the currents flowing in the M sets of winding units, the current feedback control of the rotating motor is performed.

2. The rotary electric motor control system according to claim 1, wherein, In a vector coordinate system where the direction of the magnetic flux of the permanent magnet in the rotor of the rotating electric motor is the d-axis and the q-axis is orthogonal to the d-axis, the inverter control device performs feedback control on the rotating electric motor based on the deviation between the current command based on the target torque of the rotating electric motor and the actual current. The inverter control device converts the N-phase AC current, i.e., the actual current, into a 2-phase current in the dq-axis orthogonal vector coordinate system. Based on the deviation between the current command (i.e., the two-phase current command) and the two-phase current in the orthogonal vector coordinate system of the dq axes, the two-phase voltage command in the orthogonal vector coordinate system of the dq axes is calculated. The two-phase voltage command is converted into an N-phase voltage command applied to the N-phase winding unit. The switching control signal is generated based on the N-phase voltage command.

3. The rotary electric motor control system according to claim 2, wherein, The rotary motor control system includes a rotation sensor for detecting the rotation of the rotor. The inverter control device performs coordinate transformation between the N-phase coordinate system and the dq-axis orthogonal vector coordinate system based on the rotational position of the rotor detected by the rotation sensor.

4. The rotary electric motor control system according to any one of claims 1 to 3, wherein, Each of the winding units is a three-phase winding with a star connection where the windings of each phase are connected at the neutral point.

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