Open winding motor control method, and open winding motor control device

Abstract

To provide an open winding motor control method by which a zero-phase current can be made to flow without exerting influences upon a current component for controlling torque, etc., and an open winding motor control device.SOLUTION: A first motor 10 and a second motor 11, which are open winding motors, are connected and rotated at the same rotation speed in such a manner that an electric angle θre has a predetermined phase difference θdiff that is determined beforehand. At this time, a first motor zero-phase current I01 and a second motor zero-phase current I02 are calculated and further converted into rotation coordinate system zero-phase currents (I0d, I0q) which are currents in a zero-phase rotation coordinate system that is rotated in frequencies of the first motor zero-phase current I01 and the second motor zero-phase current I02. A voltage to be applied to stator windings of the first motor 10 and the second motor 11 is then determined in such a manner that the rotation coordinate system zero-phase currents (I0d, I0q) follow rotation coordinate system zero-phase current command values (I0d*, I0q*).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method and a device for controlling an open winding motor. [Background technology]

[0002] Patent Document 1 discloses a technology for suppressing the occurrence of zero-phase current by switching two inverters that drive an open winding motor using first to third switching patterns and superimposing a correction current on the current for outputting torque. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-31458 A Summary of the Invention [Problem to be solved by the invention]

[0004] When driving an open-winding motor, a zero-sequence current is generated that circulates through the stator winding and the two inverters. The zero-sequence current increases the current that flows through the stator winding and also increases the loss in the open-winding motor. For this reason, the open-winding motor is, in principle, controlled so that the zero-sequence current is zero.

[0005] On the other hand, in recent years, there are cases where a zero-phase current is deliberately passed as necessary. However, the zero-phase current is a harmonic of the fundamental current for driving the motor, and is a high-frequency AC current. Therefore, problems arise when passing a zero-phase current.

[0006] Specifically, when harmonics are added to the fundamental wave to pass a zero-phase current, the final command value of the voltage applied to the stator winding constantly fluctuates at a high frequency. As a result, the open-winding motor, which is the object of control, drives with a delay relative to the command value. Therefore, when trying to pass a zero-phase current, there is a problem that even in a steady state where the torque, etc. is not fluctuating, the current components (dq-axis currents) for controlling the torque, etc. also fluctuate due to the effect of the delay.

[0007] When the zero-phase current is continuously suppressed, the command value for the zero-phase current is a DC signal that is substantially maintained at zero amperes, so the above-mentioned problem does not become apparent. In other words, the above-mentioned problem is unique to the case where a zero-phase current is intentionally allowed to flow.

[0008] An object of the present invention is to provide an open winding motor control method and an open winding motor control device that can pass a zero-phase current without affecting the current components for controlling torque, etc. [Means for solving the problem]

[0009] One aspect of the present invention is an open winding motor control method for rotating the first motor and the second motor at the same rotation speed in a system including a first motor and a second motor, the first motor and the second motor being open winding motors having independent stator windings of multiple phases, and the output shafts of the first motor and the second motor being connected so that the electrical angles of the first motor and the second motor have a predetermined phase difference. The open winding motor control method obtains a first motor current, which is a current flowing through the stator windings of each phase of the first motor, and a second motor current, which is a current flowing through the stator windings of each phase of the second motor, and calculates a first motor zero-phase current flowing commonly through the stator windings of each phase of the first motor based on the first motor current, and calculates a second motor zero-phase current flowing commonly through the stator windings of each phase of the second motor based on the second motor current. Furthermore, the first motor zero-phase current and the second motor zero-phase current are converted into rotating coordinate system zero-phase currents, which are currents in a zero-phase rotating coordinate system that rotates at the frequency of the first motor zero-phase current and the second motor zero-phase current, based on the electrical angle. Also, a rotating coordinate system zero-phase current command value, which is a command value for the rotating coordinate system zero-phase current, is calculated based on the required torque for the first motor and the second motor. Then, a voltage to be applied to the stator windings of the first motor and the second motor is determined so that the rotating coordinate system zero-phase current follows the rotating coordinate system zero-phase current command value. Effect of the Invention

[0010] According to the present invention, it is possible to provide an open winding motor control method and an open winding motor control device that can pass a zero-phase current without affecting the current components for controlling torque, etc. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic circuit diagram of a drive train of a vehicle drive system. [Diagram 2] FIG. 2 is an explanatory diagram showing a connection method of the first motor and the second motor. [Diagram 3] FIG. 3 is a block diagram showing a control configuration of the vehicle drive system. [Figure 4]FIG. 4 is a block diagram showing the configuration of the torque control unit. [Diagram 5] FIG. 5 is a flowchart relating to the control of the first motor and the second motor. [Figure 6] FIG. 6 is a time chart showing the dq axis currents and the zero-phase current in the comparative example. [Figure 7] FIG. 7 is a time chart showing the dq-axis currents of the first motor and the second motor, the first motor zero-phase current, and the second motor zero-phase current in this embodiment. [Figure 8] FIG. 8 is a block diagram showing a control configuration of a vehicle drive system according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] [Embodiment] Fig. 1 is a schematic circuit diagram of a drive system of a vehicle drive system 100. As shown in Fig. 1, the vehicle drive system 100 according to this embodiment is a system for driving an electrically-driven vehicle such as an electric vehicle or a hybrid vehicle, and includes a first motor 10 and a second motor 11.

[0014] Both the first motor 10 and the second motor 11 are open winding type electric motors (open winding motors). An open winding motor is a motor that does not have a so-called neutral point, has independent stator windings of multiple phases, and is driven by two inverters, one connected to one end of the stator winding and the other connected to the other end of the stator winding.

[0015] In this embodiment, the first motor 10 (first open winding motor) is a three-phase AC motor and has three-phase stator windings of UV and W. Hereinafter, when it is necessary to distinguish it from the second motor 11, the UV and W phases of the first motor 10 will be referred to as U1 phase, V1 phase, and W1 phase, respectively, and the stator windings of these phases will be referred to as stator windings U1, V1, and W1 of the first motor 10.

[0016] The first motor 10 is controlled by a first inverter 12 and a second inverter 13. The first inverter 12 is an inverter connected to one end of the stator windings U1, V1, and W1. The second inverter 13 is an inverter connected to the other end of the stator windings U1, V1, and W1. The first inverter 12 and the second inverter 13 are connected to a battery 15 via a smoothing capacitor 14 (input capacitor). The first inverter 12 and the second inverter 13 switch on / off the switching elements to convert the DC power output by the battery 15 into AC power and supply it to the stator windings U1, V1, and W1 of the first motor 10. In this way, the first motor 10 is driven.

[0017] Similarly, in this embodiment, the second motor 11 (second open winding motor) is a three-phase AC motor and has three-phase stator windings of UV and W. Hereinafter, when it is necessary to distinguish it from the first motor 10, the UV and W phases of the second motor 11 are referred to as U2 phase, V2 phase, and W2 phase, respectively, and the stator windings of these phases are referred to as stator windings U2, V2, and W2 of the second motor 11.

[0018] The second motor 11 is controlled by a third inverter 16 and a fourth inverter 17. The third inverter 16 is an inverter connected to one end of the stator windings U2, V2, and W2. The fourth inverter 17 is an inverter connected to the other end of the stator windings U2, V2, and W2. The third inverter 16 and the fourth inverter 17 are connected to a battery 15 shared with the first motor 10 via a smoothing capacitor 18 (input capacitor). The third inverter 16 and the fourth inverter 17 switch on / off the switching elements to convert the DC power output by the battery 15 into AC power and supply it to the stator windings U2, V2, and W2 of the second motor 11. This drives the second motor 11.

[0019] Hereinafter, the first inverter 12 and the second inverter 13 that control the operation of the first motor 10, and the third inverter 16 and the fourth inverter 17 that control the operation of the second motor 11 will be collectively referred to as an inverter 19 (see FIG. 3) of the vehicle drive system 100. The inverter 19 includes smoothing capacitors 14, 18, relays, and other necessary elements.

[0020] The first motor 10 and the second motor 11 can be electrically controlled independently of each other by controlling the above-mentioned inverters. However, in this embodiment, the first motor 10 and the second motor 11 are directly or indirectly connected (coupled). For example, the first motor 10 and the second motor 11 are both connected to the same drive shaft (not shown). Therefore, the first motor 10 and the second motor 11 rotate at the same rotation speed N [rpm] (rotational speed). Also, in this embodiment, the first motor 10 and the second motor 11 rotate at the same rotation speed N [rpm] (rotational speed) as the electrical angle θ of the first motor 10. re1 and the electrical angle θ of the second motor 11 re2 is a predetermined phase difference θ diff (See FIG. 2).

[0021] The battery 15 is, for example, a stacked lithium ion battery, and outputs DC power. The DC voltage output by the battery 15 (hereinafter, referred to as the power supply voltage V dc ) can be detected appropriately as necessary.

[0022] FIG. 2 is an explanatory diagram showing a connection method of the first motor 10 and the second motor 11. FIG. 2(A) is an explanatory diagram showing the first connection method. FIG. 2(B) is an explanatory diagram showing the second connection method. Here, rotation of the output shaft in the UVW directions is referred to as "forward rotation" in terms of control, and rotation of the output shaft in the UWV directions is referred to as "reverse rotation" in terms of control. In addition, the directions in which the stator windings of the UVW phases form magnetic flux are respectively shown as the UVW axes.

[0023] As shown in the upper part of FIG. 2A, the first connection method is a method of connecting the first motor 10 and the second motor 11 so that the rotation directions of the output shaft 21 of the first motor 10 and the output shaft 22 of the second motor 11 are the same. + When the first motor 10 rotates in the forward direction as shown by arrow C2 + As indicated by , the second motor 11 also rotates in the forward direction.

[0024] As shown in the lower part of FIG. 2A, the first motor 10 and the second motor 11 are arranged such that the U1 axis, the V1 axis, and the W1 axis are rotated by a predetermined angle (phase difference θ diff ) of the first motor 10. re1 and the electrical angle θ of the second motor 11 re2 is the phase difference θ diff The phase difference θ diff is preset by the physical connection angle between the first motor 10 and the second motor 11.

[0025] On the other hand, as shown in the upper part of FIG. 2(B), the second connection method is a method in which the first motor 10 and the second motor 11 are connected so that the rotation directions of the output shaft 21 of the first motor 10 and the output shaft 22 of the second motor 11 are opposite to each other. + When the first motor 10 rotates in the forward direction as shown by arrow C2 - As indicated by , the second motor 11 rotates in the reverse direction.

[0026] Also, as shown in the lower part of FIG. 2B, in the case of connection by the second connection method, the first motor 10 and the second motor 11 have a U1 axis, a V1 axis, and a W1 axis, and a U2 axis, a V2 axis, and a W2 axis that are rotated at a predetermined angle (phase difference θ diff ) of the first motor 10. re1 and the electrical angle θ of the second motor 11 re2 is the phase difference θ diff It changes while maintaining this.

[0027] As described above, there are the first and second connection methods according to the physical arrangement, but in terms of control, either connection method can be treated substantially the same. For example, in the second connection method, if the V2 phase and W2 phase (i.e., the forward and reverse directions) of the second motor 11 are swapped, it can be treated substantially the same as the first connection method. In this embodiment, unless otherwise specified, the first motor 10 and the second motor 11 are assumed to be connected by the first connection method.

[0028] 3 is a block diagram showing a control configuration of the vehicle drive system 100. As shown in FIG.

[0029] The controller 25 is a control device (open winding motor control device) that comprehensively controls the operation of the first motor 10 and the second motor 11, which are open winding motors. The controller 25 is configured, for example, with one or more computers. A program (open winding motor control program) that the controller 25 executes to control the operation of the first motor 10 and the second motor 11 can be provided, for example, in a format stored in a recording medium.

[0030] The controller 25 controls the rotation states of the first motor 10 and the second motor 11 and the current I U1 ,I V1 ,I W1 ,I U2 ,I V2 ,I W2 Based on the above, a PWM (Pulse Width Modulation) signal D is generated that commands the timing to turn on / off the switching element. U1 ,D V1 ,D W1 ,D U2 ,D V2 ,D W2 The controller 25 generates the PWM signal D U1 ,D V1 ,D W1 ,D U2 ,DV2 ,D W2 The operation of the first motor 10 and the second motor 11 is controlled by inputting the above-mentioned signal to the inverter 19.

[0031] Specifically, the controller 25 includes a rotation state detection unit 31, a three-phase current coordinate conversion unit 32, a zero-phase current coordinate conversion unit 33, a torque control unit 34, a zero-phase voltage coordinate conversion unit 35, a three-phase voltage coordinate conversion unit 36, and a PWM conversion unit 37.

[0032] The rotation state detection unit 31 calculates parameters representing the rotation states of the first motor 10 and the second motor 11 based on the rotor positions (angles) of the first motor 10 and the second motor 11. In this embodiment, the rotation state detection unit 31 calculates parameters representing the rotation states of the first motor 10 and the second motor 11 based on the rotor positions (angles) of the first motor 10 and the second motor 11. re , phase difference θ diff , and electrical angular velocity ω re The rotation state detection unit 31 can also calculate parameters indicating other rotation states, such as the rotation speeds N of the first motor 10 and the second motor 11, as necessary.

[0033] Specifically, the rotation state detection unit 31 acquires so-called A-phase, B-phase, and Z-phase pulses (hereinafter referred to as ABZ pulses) from a magnetic pole position detector 41 provided in the first motor 10. Based on the ABZ pulse (ABZ1) acquired from the magnetic pole position detector 41, the rotation state detection unit 31 determines the electrical angle θ of the first motor 10. re1 Similarly, the rotation state detection unit 31 acquires an ABZ pulse (ABZ2) from a magnetic pole position detector 42 provided in the second motor 11. The rotation state detection unit 31 calculates the electrical angle θ of the second motor 11 based on the ABZ pulse (ABZ2) acquired from the magnetic pole position detector 42. re2 Calculate the following.

[0034] In this embodiment, the electrical angle θ re1 ,θ re2 Specifying the electrical angle (θ re ) and phase difference θ diff For example, the electrical angle θ of the first motor 10 is re1 θ re", the electrical angle θ of the first motor 10 is re1 and the electrical angle θ of the second motor 11 re2 is the phase difference θ diff In this embodiment, the rotation state detection unit 31 detects the electrical angle θ of the first motor 10. re1 The representative electrical angle θ re And this electrical angle θ re and phase difference θ diff Output.

[0035]

number

[0036] The rotation state detector 31 detects a phase difference θ diff In this case, the electrical angle θ re1 ,θ re2 can be obtained from either one according to the formula (1). For this reason, it is sufficient that only one of the magnetic pole position detectors 41 and 42 is provided.

[0037] The rotation state detection unit 31 detects the electrical angle θ of the first motor 10. re1 By differentiating the electric angular velocity ω re1 Similarly, the rotation state detection unit 31 can calculate the electrical angle θ of the second motor 11. re2 By differentiating the electric angular velocity ω re2 In this embodiment, the electrical angular velocity ω of the first motor 10 can be calculated. re1 and the electrical angular velocity ω of the second motor 11 re2 is the same value (hereinafter, simply the electrical angular velocity ω re For this reason, the rotation state detection unit 31 detects the electrical angle θ of the first motor 10. re1 Or the electrical angle θ of the second motor 11 re2 By differentiating the electrical angular velocity ω re Calculate and output.

[0038] The three-phase current coordinate conversion unit 32 converts the electrical angle θ re and phase difference θ diff Based on this, the current flowing through each phase of the first motor 10 (hereinafter referred to as the first motor current I U1 ,I V1 ,I W1 The three-phase current coordinate converter 32 converts the d-axis current I d1 , q-axis current I q1 , and zero-phase current I 01 Calculate the first motor current I U1 ,I V1 ,I W1 is detected by the current detector 43.

[0039]

number

[0040] The zero-phase current is a current that flows in phase with each phase in a multi-phase unbalanced AC circuit. Therefore, the zero-phase current I 01 (Hereinafter, the first motor zero-phase current I 01 The first motor current I U1 ,I V1 ,I W1 In other words, the first motor zero-phase current I 01 represents the current circulating through the stator windings U1, V1, and W1 and the inverter 19 (the first inverter 12 and the second inverter 13). As can be seen from equation (2), the first motor zero-phase current I 01 is the first motor current I U1 ,I V1 ,I W1 It is expressed as the sum of

[0041] The first motor current I U1 ,I V1 ,I W1The current component for controlling the torque, rotation speed, etc. of the first motor 10 has a frequency of θ re On the other hand, the first motor zero-phase current I 01 are harmonics. More specifically, the first motor zero-phase current I 01 is a harmonic having an order that is an integer multiple of the number of phases (in this embodiment, "3"). In the following, for simplicity, the first motor zero-phase current I 01 is the third harmonic (frequency is 3θ re / 2π AC current). Also, the fundamental frequency θ re / 2π is called the fundamental frequency, and the first motor zero-phase current I 01 Frequency 3θ re / 2π is called the zero-phase frequency.

[0042] Similarly to the above, the three-phase current coordinate conversion unit 32 converts the electrical angle θ re and phase difference θ diff Based on this, the current I flowing through each phase of the second motor 11 is U2 ,I V2 ,I W2 (Hereinafter, the second motor current I U2 ,I V2 ,I W2 The three-phase current coordinate converter 32 converts the d-axis current I d2 , q-axis current I q2 , and zero-phase current I 02 Calculate the second motor current I U2 ,I V2 ,I W2 is detected by the current detector 44.

[0043]

number

[0044] Zero-phase current I of the second motor 11 02 (Hereinafter, the second motor zero-phase current I 02 The second motor current IU2 ,I V2 ,I W2 This is the current component that flows in common to the stator windings U2, V2, and W2, and represents the current that circulates through the stator windings U2, V2, and W2 and the inverter 19 (the third inverter 16 and the fourth inverter 17). As can be seen from equation (3), the second motor zero-phase current I 02 is the second motor current I U2 ,I V2 ,I W2 The second motor zero-phase current I 02 The fact that is a harmonic is due to the first motor zero-phase current I 01 For simplicity, the second motor zero-phase current I 02 is also assumed to be the third harmonic.

[0045] Second motor current I U2 ,I V2 ,I W2 The current component for controlling the torque, rotation speed, etc. of the second motor 11 has a frequency of θ re / 2π AC current (fundamental wave). Also, the zero-phase current I 02 are its harmonics. Therefore, the zero-phase frequency is the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is common to all.

[0046] The first motor current I U1 ,I V1 ,I W1 is an AC current, while the dq-axis current I d1 ,I q1 is a DC current in the dq coordinate system (dq0 coordinate system). On the other hand, the first motor zero-phase current I 01 is still an AC current in the dq coordinate system (dq0 coordinate system). Similarly, the second motor current I U2 ,I V2 ,I W2 is an AC current, while the dq-axis current I d2 ,I q2 is a DC current in the dq coordinate system (dq0 coordinate system). On the other hand, the second motor zero-phase current I 02is still an AC current in the dq coordinate system (dq0 coordinate system).

[0047] In this embodiment, for simplicity, the three-phase current coordinate conversion unit 32 converts the motor current into a current in a rotating coordinate system (dq coordinate system) in which two axes are orthogonal, but the three-phase current coordinate conversion unit 32 can also convert the motor current into a current in a non-orthogonal rotating coordinate system. The three-phase current coordinate conversion unit 32 converts the first motor zero-phase current I 01 and the second motor zero-phase current I 02 It can also be said that the zero-phase current calculation unit calculates the following:

[0048] The zero-phase current coordinate conversion unit 33 converts the first motor zero-phase current I 01 and the second motor zero-phase current I 02 are converted into currents in a rotating coordinate system (hereinafter referred to as the zero-phase rotating coordinate system) that rotates in synchronization with these frequencies (zero-phase frequencies).

[0049] In this embodiment, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 The frequency f0 (not shown) is 3θ re / 2π, and the rotational angular velocity ω0 (not shown) of the zero-phase rotating coordinate system is 3θ re As a result, the zero-phase current coordinate conversion unit 33 converts the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is converted to a DC current representation in the zero-phase rotating coordinate system (hereinafter referred to as the rotating coordinate system zero-phase current). In the following, following the dq coordinate transformation for the motor current (three-phase current), for the sake of convenience, the first axis of the zero-phase rotating coordinate system is referred to as the zero-phase d-axis, and the second axis is referred to as the zero-phase q-axis. Also, the zero-phase d-axis component of the rotating coordinate system zero-phase current is referred to as the zero-phase d-axis current I 0d The zero-phase q-axis component is called the zero-phase q-axis current I 0q He said.

[0050] Specifically, when the first motor 10 and the second motor 11 are connected in the first connection manner, the zero-phase current coordinate conversion unit 33 converts the first motor zero-phase current I 01 and the second motor zero-phase current I02 From the zero-phase dq axis current I 0d ,I 0q Calculate the following.

[0051]

number

[0052] In addition, when the first motor 10 and the second motor 11 are connected in the second connection method, the zero-phase current coordinate conversion unit 33 converts the first motor zero-phase current I 01 and the second motor zero-phase current I 02 From the zero-phase dq axis current I 0d ,I 0q However, as described above, for example, when the V2 phase and the W2 phase of the second motor 11 are interchanged for control purposes, even if the first motor 10 and the second motor 11 are connected in the second connection method, the zero-phase current coordinate conversion unit 33 calculates the first motor zero-phase current I according to the above formula (4). 01 and the second motor zero-phase current I 02 From the zero-phase dq axis current I 0d ,I 0q can be calculated.

[0053]

number

[0054] If the amplitude of the zero-phase current in the rotating coordinate system is I0 and the phase is β0, the zero-phase dq-axis current I 0d ,I 0q is expressed by the following equation (6). At this time, the first motor zero-phase current I 01 , and the second motor zero-phase current I 02 is expressed by the following equation (7).

[0055]

number

[0056] As can be seen from equation (7), the phase difference θ diffWhen is 0 [rad], the first motor zero-phase current I 01 and the second motor zero-phase current I 02 are in phase, making it difficult to convert to a zero-phase rotating coordinate system. diff When is π [rad], the first motor zero-phase current I 01 and the second motor zero-phase current I 02 Therefore, the first motor 10 and the second motor 11 have a phase difference θ diff The phase difference θ is connected so that it is not 0 or π (hereinafter referred to as a specific phase difference). diff is the first motor zero-phase current I 01 and the second motor zero-phase current I 02 However, if the conversion of the zero-phase rotating coordinate system is practically possible depending on the specific calculation accuracy, etc., the phase difference θ diff In this embodiment, the first motor 10 and the second motor 11 have a phase difference θ diff is connected so that it is approximately π / 2.

[0057] The first motor 10 and the second motor 11 are connected in the second connection method, and the zero-phase current I 01 and the second motor zero-phase current I 02 From the zero-phase dq axis current I 0d ,I 0q When calculating the zero-phase dq-axis current I 0d ,I 0q When expressing the first motor zero-phase current I 01 , and the second motor zero-phase current I 02 is expressed by the following equation (8).

[0058]

number

[0059] In this embodiment, for simplicity, the two axes of the zero-phase rotating coordinate system, i.e., the zero-phase d-axis and the zero-phase q-axis, are assumed to be perpendicular to each other. However, a zero-phase rotating coordinate system in which the two axes are not perpendicular to each other can also be used.

[0060] The torque control unit 34 controls the dq-axis voltage command value V d1 * ,V q1 * , the dq-axis voltage command value V d2 * ,V q2 * , zero-phase dq-axis voltage command value V 0d * ,V 0q * (Rotating coordinate system zero-phase voltage command), and look-ahead compensation electrical angle θ re Calculate '.

[0061] The dq-axis voltage command value V of the first motor 10 d1 * ,V q1 * is the dq-axis voltage V of the first motor 10 d1 ,V q1 The dq-axis voltage command value V d2 * ,V q2 * is the dq-axis voltage V of the second motor 11 d2 ,V q2 The zero-phase dq-axis voltage command value V 0d * ,V 0q * is the voltage in the zero-phase rotating coordinate system, i.e., the zero-phase d-axis voltage V 0d and the zero-phase q-axis voltage V 0q The look-ahead compensation electrical angle θ re ' is an electrical angle in which the influence of the dead time of the control system (vehicle drive system 100) has been compensated in advance.

[0062] The torque control unit 34 calculates the above parameters as the dq-axis current I d1 ,I q1 , the dq-axis current I of the second motor 11d2 ,I q2 , electrical angle θ re , phase difference θ diff , electrical angular velocity ω re , the required torque T1 for the first motor 10 * , the required torque T2 for the second motor 11 * , and power supply voltage V dc The required torque T1 for the first motor 10 and the second motor 11 is calculated based on the above. * ,T2 * is determined by the rotation speed N of the first motor 10 and the second motor 11, the operation amount of the accelerator pedal, etc. In this embodiment, the required torque T1 * ,T2 * is assumed to be given. The power supply voltage V dc is suitably detected by the voltage sensor 45.

[0063] The calculations performed by the torque control unit 34 will be described in detail later.

[0064] The zero-phase voltage coordinate conversion unit 35 converts the zero-phase dq-axis voltage command value V 0d * ,V 0q * From the above, the zero-phase voltage command value V 01 * and the zero-phase voltage command value V for the second motor 11. 02 * Specifically, the zero-phase voltage coordinate conversion unit 35 calculates the electrical angle θ re and phase difference θ diff Based on this, the zero-phase voltage command value V 01 * ,V 02 * Calculate the following.

[0065]

number

[0066] The three-phase voltage coordinate conversion unit 36 ​​converts the electrical angle θre and phase difference θ diff The dq-axis voltage command value V of the first motor 10 is calculated by the coordinate transformation based on d1 * ,V q1 * , and the zero-phase voltage command value V 01 * From the above, the three-phase voltage command value V U1 * ,V V1 * ,V W1 * The three-phase voltage command value V U1 * ,V V1 * ,V W1 * are command values ​​that determine the voltages to be applied to the stator windings U1, V1, and W1 of the first motor 10.

[0067] In addition, the three-phase voltage coordinate conversion unit 36 ​​converts the electrical angle θ re and phase difference θ diff The dq-axis voltage command value V of the second motor 11 is calculated by the coordinate transformation based on d2 * ,V q2 * , and the zero-phase voltage command value V 02 * From the above, the three-phase voltage command value V U2 * , V V2 * ,V W2 * The three-phase voltage command value V U2 * ,V V2 * ,V W2 * are command values ​​for determining the voltages to be applied to the stator windings U2, V2, and W2 of the second motor 11.

[0068] Specifically, the three-phase voltage coordinate conversion unit 36 ​​calculates the three-phase voltage command value V for the first motor 10 according to the following equations (10) and (11): U1 * ,V V1 *,V W1 * , and the three-phase voltage command value V U2 * , V V2 * ,V W2 * Calculate the following.

[0069]

number

[0070] However, in this embodiment, the torque control unit 34 sets the look-ahead compensation electrical angle θ re ', the three-phase voltage coordinate conversion unit 36 ​​calculates the electrical angle θ re Instead of this, the look-ahead compensation electrical angle θ re That is, the three-phase voltage coordinate conversion unit 36 ​​uses the electrical angle θ re Look ahead and calculate the compensation electrical angle θ re This allows the three-phase voltage command value V U1 * ,V V1 * ,V W1 * and the three-phase voltage command value V U2 * , V V2 * ,V W2 * is calculated.

[0071] The PWM conversion unit 37 converts the three-phase voltage command value V U1 * ,V V1 * ,V W1 * , and power supply voltage V dc Based on this, a PWM signal D is generated to drive the switching elements of the first inverter 12 and the second inverter 13. U1 ,D V1 ,D W1 Similarly, the PWM conversion unit 37 generates a three-phase voltage command value V U2* , V V2 * ,V W2 * , and power supply voltage V dc Based on this, a PWM signal D is generated to drive the switching elements of the third inverter 16 and the fourth inverter 17. U2 ,D V2 ,D W2 The PWM conversion unit 37 generates these PWM signals D U1 ,D V1 ,D W1 ,D U2 ,D V2 ,D W2 The operation of the first motor 10 and the second motor 11 is controlled by inputting the above-mentioned signal to the inverter 19.

[0072] Fig. 4 is a block diagram showing the configuration of the torque control unit 34. As shown in Fig. 4, the torque control unit 34 includes a fundamental wave current command value calculation unit 51, a zero-phase current command value calculation unit 52, a look-ahead compensation unit 53, a feedback voltage calculation unit 54, a decoupling voltage calculation unit 55, and a voltage command value calculation unit 56.

[0073] The fundamental wave current command value calculation unit 51 calculates the required torque T1 for the first motor 10. * and electrical angular velocity ω re and the power supply voltage V dc Based on this, the dq-axis current command value I d1 * ,I q1 * Calculate the dq axis current command value I d1 * ,I q1 * is the required torque T1 * In order to cause the first motor 10 to output a torque T1 corresponding to d1 ,I q1 The dq-axis current command value I d1* ,I q1 * is the final first motor current I U1 ,I V1 ,I W1The fundamental wave component in is commanded in the dq coordinate system (dq0 coordinate system).

[0074] In this embodiment, the fundamental wave current command value calculation unit 51 calculates the required torque T1 * , electrical angular velocity ω re , and power supply voltage V dc and the dq-axis current command value I d1 * ,I q1 * The fundamental wave current command value calculation unit 51 has a first fundamental wave current command value map (not shown) in which the first fundamental wave current command value and the second fundamental wave current command value are associated with each other in advance by an experiment, a simulation, or the like. Therefore, the fundamental wave current command value calculation unit 51 can calculate the required torque T1 * , electrical angular velocity ω re , and power supply voltage V dc The dq-axis current command value I d1 * ,I q1 * Calculate the following.

[0075] Similarly, the fundamental wave current command value calculation unit 51 calculates the required torque T2 * and electrical angular velocity ω re and the power supply voltage V dc Based on this, the dq-axis current command value I d2 * ,I q2 * Calculate the dq axis current command value I d2 * ,I q2 * is the required torque T2 * In order to cause the second motor 11 to output a torque T2 corresponding to d2 ,I q2 The dq-axis current command value I d2* ,I q2 * is the final second motor current I U2 ,I V2 ,I W2 The fundamental wave component in is commanded in the dq coordinate system (dq0 coordinate system).

[0076] In this embodiment, the fundamental wave current command value calculation unit 51 calculates the required torque T2 * , electrical angular velocity ω re , and power supply voltage V dc and the dq-axis current command value I d2 * ,I q2 * A second fundamental wave current command value map (not shown) is provided in which the second fundamental wave current command value and the second fundamental wave current command value are associated in advance by experiments, simulations, or the like. Therefore, the fundamental wave current command value calculation unit 51 can calculate the required torque T2 * , electrical angular velocity ω re , and power supply voltage V dc The dq-axis current command value I d2 * ,I q2 * Calculate the following.

[0077] The zero-phase current command value calculation unit 52 calculates the required torque T1 for the first motor 10 and the second motor 11. * ,T2 * and electrical angular velocity ω re and the power supply voltage V dc Based on this, the zero-phase d-axis current command value I d0 * and the zero-phase q-axis current command value I q0 * Calculate the zero-phase dq-axis current command value I d0 * ,I q0 * is the command value of the zero-phase current in the zero-phase rotating coordinate system (rotating coordinate system zero-phase current command value). The first motor zero-phase current I 01 and the second motor zero-phase current I 02 When maintaining the zero-phase dq-axis current command value I d0 * ,I q0 * However, in this embodiment, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 In this case, the zero-phase dq-axis current command value I d0* ,I q0 * At least one of these is a non-zero value. In the following, in principle, the zero-phase dq-axis current command value I d0 * ,I q0 * are all assumed to be non-zero values.

[0078] In this embodiment, the zero-phase current command value calculation unit 52 calculates the required torque T1 * ,T2 * , electrical angular velocity ω re , and power supply voltage V dc and the zero-phase d-axis current command value I d0 * and the zero-phase q-axis current command value I q0 * The zero-phase current command value calculation unit 52 has a zero-phase current command value map in which the required torque T1 and the required torque T2 are previously associated with each other through experiments, simulations, or the like. Therefore, the zero-phase current command value calculation unit 52 can calculate the required torque T1 by referring to the zero-phase current command value map. * ,T2 * , electrical angular velocity ω re , and power supply voltage V dc The zero-phase dq-axis current command value I d0 * ,I q0 * Calculate the following.

[0079] The look-ahead compensation unit 53 calculates the electrical angle θ re and electrical angular velocity ω re Based on this, the look-ahead compensation electrical angle θ re Specifically, the dead time of the control system and the electrical angular velocity ω re The multiplied value is expressed as the electrical angle θ re By adding to the above, the look-ahead compensation electrical angle θ re Calculate '.

[0080] The feedback voltage calculation unit 54 calculates a voltage (hereinafter referred to as feedback voltage) for making the deviation between the actual current value (detected value) and the current command value zero and for making the actual current value follow the current command value.

[0081] Specifically, the feedback voltage calculation unit 54 calculates the dq-axis current I d1 ,I q1 (detection value) and the dq-axis current command value I d1 * ,I q1 * Based on this, the dq-axis feedback voltage V d1-FB ,V q1-FB Calculate the dq axis feedback voltage V d1-FB ,V q1-FB is the dq axis current I d1 ,I q1 The dq-axis current command value I d1 * ,I q1 * In order to make the first motor 10 follow the d1 ,V q1 Represents.

[0082] The feedback voltage calculation unit 54 calculates the d-axis feedback voltage V d1-FB can be calculated by the PI control expressed by the following formula (12), for example. In formula (12), "s" is the Laplace operator. pd " is the proportional gain, and "k id " is the integral gain. The proportional gain k pd and integral gain k id is the d-axis inductance L of the first motor 10 d , winding resistance R, and dq-axis current I d1 ,I q1 Using the standard response time constant τ, it is expressed by the following equation (13). Here, the d-axis feedback voltage V d1-FB The calculation method of the q-axis feedback voltage V q1-FB can be calculated similarly by PI control.

[0083]

number

[0084] The feedback voltage calculation unit 54 calculates the dq-axis current I d2 ,I q2 (detection value) and the dq-axis current command value I d2 * ,I q2 * Based on this, the dq-axis feedback voltage V d2-FB ,V q2-FB Calculate the dq axis feedback voltage V d2-FB ,V q2-FB is the dq axis current I d2 ,I q2 The dq-axis current command value I d2 * ,I q2 * In order to make the second motor 11 follow the d2 ,V q2 The feedback voltage calculation unit 54 calculates the dq-axis feedback voltage V d2-FB ,V q2-FB The dq-axis feedback voltage V d1-FB ,V q1-FB Similarly, it is calculated by, for example, PI control.

[0085] Furthermore, the feedback voltage calculation unit 54 calculates the zero-phase dq-axis current I 0d ,I 0q (detection value) and the zero-phase dq-axis current command value I 0d * ,I 0q * Based on this, the zero-phase dq-axis feedback voltage V 0d-FB ,V 0q-FB Calculate the zero-phase dq-axis feedback voltage V 0d-FB ,V 0q-FB is the zero-phase dq-axis current I 0d ,I 0q The zero-phase dq-axis current command value I 0d * ,I 0q * The zero-phase dq-axis voltage V that should be applied to make it follow 0d ,V 0qThe feedback voltage calculation unit 54 calculates the zero-phase dq-axis feedback voltage V 0d-FB ,V 0q-FB , the dq axis feedback voltage V d1-FB ,V q1-FB ,V d2-FB ,V q2-FB However, the zero-phase dq-axis feedback voltage V 0d-FB ,V 0q-FB In the PI control for calculating the above, the proportional gain and the integral gain are determined in advance by an experiment or a simulation.

[0086] The decoupling voltage calculation unit 55 calculates the dq-axis voltage V d1 ,V q1 , the dq-axis voltage V of the second motor 11 d2 ,V q2 , and the zero-phase dq-axis voltage V 0d ,V 0q Specifically, the decoupling voltage calculation unit 55 calculates a voltage for decoupling the dq-axis voltage V d1 ,V q1 The dq-axis voltage V of the second motor 11 d2 ,V q2 and the zero-phase dq-axis voltage V 0d ,V 0q The dq-axis decoupling voltage V d1-dcpl ,V q1-dcpl The non-interfering voltage calculation unit 55 calculates the dq-axis voltage V d2 ,V q2 The dq-axis voltage V of the first motor 10 d1 ,V q1 and the zero-phase dq-axis voltage V 0d ,V 0q The dq-axis decoupling voltage V d2-dcpl ,V q2-dcpl Furthermore, the decoupling voltage calculation unit 55 calculates the zero-phase dq-axis voltage V 0d ,V 0q The dq-axis voltage V of the first motor 10 d1 ,V q1 and the dq-axis voltage V of the second motor 11 d2 ,Vq2 Zero-phase dq-axis decoupling voltage V 0d-dcpl ,V 0q-dcpl Calculate the following.

[0087] The non-interfering voltage calculation unit 55 calculates the dq-axis current command value I d1 * ,I q1 * , the dq-axis current command value I d2 * ,I q2 * , zero-phase dq-axis current command value I 0d * ,I 0q * , electrical angle θ re , phase difference θ diff , and electrical angular velocity ω re The above-mentioned decoupling voltage is calculated based on the above.

[0088] The decoupling voltage is the dq-axis voltage V of the first motor 10. d1 ,V q1 , the dq-axis voltage V of the second motor 11 d2 ,V q2 , and the zero-phase dq-axis voltage V 0d ,V 0q The off-diagonal terms of the 6 × 6 matrix in the voltage equation consisting of six axes and the current command value (I d1 * ,I q1 * ,I d2 * ,I q2 * ,I 0d * ,I 0q * ) multiplied by a first-order filter with a standard response time constant τ, and the sum of these and the induced voltage due to the magnet magnetic flux. The off-diagonal terms of the voltage equation for the six axes are represented by the winding resistances and inductances of the first motor 10 and the second motor 11.

[0089] In this embodiment, the non-interfering voltage calculation unit 55 calculates the non-interfering voltage using a current command value (I d1* ,I q1 * ,I d2 * ,I q2 * ,I 0d * ,I 0q * ) is not limited to this. The non-interfering voltage calculation unit 55 uses the detected current value (I d1 ,I q1 ,I d2 ,I q2 ,I 0d ,I 0q ) can be used to calculate the decoupling voltage.

[0090] In addition, the non-interfering voltage calculation unit 55 of this embodiment calculates the electrical angle θ re Instead of this, the look-ahead compensation electrical angle θ re As a result, the dq-axis voltage V d1 ,V q1 , the dq-axis voltage V of the second motor 11 d2 ,V q2 , or zero-phase dq-axis voltage V 0d ,V 0q Even if some disturbance occurs, such as when the voltage Vcc suddenly changes, the influence of the disturbance is reduced by the decoupling voltage.

[0091] The voltage command value calculation unit 56 calculates a final voltage command value based on the feedback voltage and the non-interacting voltage. Specifically, the voltage command value calculation unit 56 calculates the dq-axis voltage command value V d1 * ,V q1 * , the dq-axis voltage command value V d2 * ,V q2 * , and the zero-phase dq-axis voltage command value V 0d * ,V 0q * Calculate the following.

[0092]

number

[0093] Hereinafter, the operation of controlling the first motor 10 and the second motor 11 in the vehicle drive system 100 configured as above will be described.

[0094] 5 is a flowchart relating to the control of the first motor 10 and the second motor 11. As shown in FIG. 5, in step S10, the rotation state detection unit 31 detects an electrical angle θ re , phase difference θ diff , and electrical angular velocity ω re In step S11, the three-phase current coordinate conversion unit 32 converts the first motor current I U1 ,I V1 ,I W1 and the second motor current I U2 ,I V2 ,I W2 From the above, the dq-axis current I d1 ,I q1 , the dq-axis current I of the second motor 11 d2 ,I q2 , the first motor zero-phase current I 01 , and the second motor zero-phase current I 02 At this stage, the dq-axis current I d1 ,I q1 and the dq-axis current I of the second motor 11 d2 ,I q2 is expressed as a direct current, but the first motor zero-phase current I 01 and the second motor zero-phase current I 02 Therefore, in step S12, the zero-phase current coordinate conversion unit 33 converts the first motor zero-phase current I 01 and the second motor zero-phase current I 02 From the above, the zero-phase dq-axis current I 0d ,I 0q As a result, the zero-phase currents of the first motor 10 and the second motor 11 are expressed as DC.

[0095] After that, in step S13, the fundamental wave current command value calculation unit 51 calculates the dq-axis current command value I d1 * ,I q1 * and the dq-axis current command value I d2 * ,I q2 * In addition, the zero-phase current command value calculation unit 52 calculates the zero-phase dq-axis current command value I 0d * ,I 0q * That is, in this embodiment, a current command value (I d1 * ,I q1 * ,I d2 * ,I q2 * ), as well as the current command value (I 0d * ,I 0q * ) is also a command value expressed as a DC current.

[0096] In step S14, the look-ahead compensation unit 53 calculates the look-ahead compensation electrical angle θ re Calculate '.

[0097] In step S15, the feedback voltage calculation unit 54 calculates the dq-axis current (I d1 ,I q1 ,I d2 ,I q2 ) and zero-phase dq-axis current (I 0d ,I 0q ) to the current command value (I d1 * ,I q1 * ,I d2 * ,I q2 * ,I 0d * ,I 0q *) to track the feedback voltage (V d1-FB ,V q1-FB ,V d2-FB ,V q2-FB ,V 0d-FB ,V 0q-FB ) are calculated. All of these feedback voltages are expressed as DC voltages.

[0098] In step S16, the non-interacting voltage calculation unit 55 calculates the look-ahead compensation electrical angle θ re dq-axis voltage V of the first motor 10 d1 ,V q1 , the dq-axis voltage V of the second motor 11 d2 ,V q2 , and the zero-phase dq-axis voltage V 0d ,V 0q The decoupling voltage (V d1-dcpl ,V q1-dcpl ,V d2-dcpl ,V q2-dcpl ,V 0d-dcpl ,V 0q-dcpl ) is calculated.

[0099] Then, in step S17, the voltage command value calculation unit 56 calculates the feedback voltage (V d1-FB ,V q1-FB ,V d2-FB ,V q2-FB ,V 0d-FB ,V 0q-FB ) and decoupling voltage (V d1-dcpl ,V q1-dcpl ,V d2-dcpl ,V q2-dcpl ,V 0d-dcpl ,V 0q-dcpl ) to obtain the final voltage command value (V d1 * ,V q1 * ,V d2 * ,V q2 * ,V 0d * ,V 0q * ) is calculated.

[0100] After that, in step S18, the zero-phase voltage coordinate conversion unit 35 converts the zero-phase dq-axis voltage command value V 0d * ,V 0q * The zero-phase voltage command value V 01 * ,V 02 * Return to.

[0101] In step S19, the three-phase voltage coordinate conversion unit 36 ​​converts the voltage command value (V d1 * ,V q1 * ,V d2 * ,V q2 * ,V 01 * ,V 02 * ), the voltage command value in the UVW coordinate system, that is, the three-phase voltage command value (V U1 * ,V V1 * ,V W1 * ,V U2 * , V V2 * ,V W2 * ) is calculated. Then, the PWM conversion unit 37 calculates these three-phase voltage command values ​​(V U1 * ,V V1 * ,V W1 * ,V U2 * , V V2 * ,V W2 * ) based on the PMW signal (D U1 ,D V1 ,D W1 ,D U2 ,D V2 ,D W2 ) drives the first motor 10 and the second motor 11.

[0102] As described above, in this embodiment, when controlling the operation of the first motor 10 and the second motor 11, which are open winding motors, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 Instead of controlling it as an AC representation, we use a DC representation in the zero-phase rotating coordinate system (zero-phase dq axis current I 0d ,I 0q ) and controls it. In other words, in this embodiment, the zero-phase current, which conventionally had to be handled as it is in AC representation, can be handled by converting it into DC representation like the dq axis current. As a result, the zero-phase current (I 0d ,I 0q ) to its command value (I 0d * ,I 0q * In particular, it is possible to make the zero-phase current (I 0d ,I 0q ) flows, the zero-phase current (I 0d ,I 0q ) is the command value (I 0d * ,I 0q * ) without delay.

[0103] FIG. 6 shows the dq-axis current I d ,I q 1 is a time chart showing the dq-axis current I and the zero-phase current I0 in a vehicle drive system having one open winding motor. d ,I q The dq-axis current command value I d * ,I q * In addition, the zero-phase current I0 is controlled to follow the zero-phase current command value I0 * In the comparative example, the zero-phase current I0 and the zero-phase current command value I0 * is an AC current. That is, the comparative example is an example in which the zero-phase current I0 is controlled as it is in the AC representation. Therefore, in the comparative example, the zero-phase current command value I0 * vibrates violently.

[0104] Figure 6(A) shows the d-axis current I d and d-axis current command value I d * Fig. 6(B) shows the q-axis current I q and q-axis current command value I q * FIG. 6(C) shows the zero-phase current I0 and the zero-phase current command value I0 * FIG. 6D is a partially enlarged view of FIG. 6C. In this figure, during the period from time t0 to time t1, the dq-axis current I d ,I q At time t1, the zero-phase current I0 flows while maintaining the zero-phase current I at zero. d ,I q Then, from time t2 onwards, the dq-axis current I d ,I q While flowing, the zero-phase current I0 is controlled to zero.

[0105] As shown in FIG. 6C, even when the zero-phase current I0 is controlled as it is expressed as an AC current as in the comparative example, the zero-phase current I0 is generally equal to or smaller than the zero-phase current command value I0 * However, as shown in FIG. 6(D), the actual zero-phase current I0 follows the zero-phase current command value I0 * Delayed relative to.

[0106] As shown in Fig. 6(A) and Fig. 6(B), the influence of the delay of the zero-phase current I0 is d ,I q That is, the dq axis current I d ,I q is a constant dq-axis current command value I d * ,I q * Although the zero-phase current command value I0 * As shown after time t2, if the flow of the zero-phase current I0 is stopped, the dq-axis current I d ,I q The vibration also subsides.

[0107] FIG. 7 shows the dq-axis current I d1 ,I q1 ,I d2 ,I q2 , the first motor zero-phase current I 01 , and the second motor zero-phase current I 02 6 is a time chart showing the above.

[0108] FIG. 7A shows the d-axis current I d1 and d-axis current command value I d1 * FIG. 7B shows the q-axis current I q1 and q-axis current command value I q1 * FIG. 7C shows the d-axis current I d2 and d-axis current command value I d2 * FIG. 7D shows the q-axis current I q2 and q-axis current command value I q2 * Fig. 7(E) shows the zero-phase d-axis current I 0d and the zero-phase d-axis current command value I 0d * Fig. 7(F) shows the zero-phase q-axis current I 0q and zero-phase q-axis current I 0q * FIG. 7(G) shows the first motor zero-phase current I 01 and the first motor zero-phase current command value I 01 * The first motor zero-phase current command value I 01 * is the zero-phase dq-axis current command value I d * ,I q * FIG. 7(H) is a partial enlarged view of FIG. 7(G). FIG. 7(I) shows the second motor zero-phase current I 02 and the second motor zero-phase current command value I 02 * The second motor zero-phase current command value I 02 * is the zero-phase dq-axis current command value Id * ,I q * 7(J) is a partially enlarged view of FIG.

[0109] The times t0, t1, and t2 are the same as those in FIG. 6. That is, in the period from time t0 to time t1, the dq-axis currents I d1 ,I q1 ,I d2 ,I q2 While keeping the first motor zero-phase current I 01 and the second motor zero-phase current I 02 Then, at time t1, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 While flowing, the dq-axis current I d1 ,I q1 ,I d2 ,I q2 After time t2, the d-axis current I d1 ,I q1 ,I d2 ,I q2 While flowing, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is controlled to zero.

[0110] As shown in FIG. 7E and FIG. 7F, in this embodiment, the zero-phase current is expressed as a zero-phase dq-axis current I 0d ,I 0q and the zero-phase dq-axis current command value I 0d * ,I 0q * Therefore, the response of the zero-phase current in this embodiment is controlled by the dq-axis current I d1 ,I q1 ,I d2 ,I q2 As with the above, it is a first-order delay response. Therefore, feedback control (V 0d-FB ,V 0q-FBThe zero-phase dq-axis current I 0d ,I 0q is the zero-phase dq-axis current command value I 0d * ,I 0q * It tracks with high accuracy.

[0111] Therefore, in this embodiment, as shown in FIG. 7(G) to FIG. 7(I), the harmonic first motor zero-phase current I 01 and the second motor zero-phase current I 02 Even if the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is the command value I 01 * ,I 02 * As a result, as shown in Figs. 7(A) to 7(D), the dq-axis currents I d1 ,I q1 ,I d2 ,I q2 In other words, according to this embodiment, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is the dq-axis current I of the first motor 10 and the second motor 11. d1 ,I q1 ,I d2 ,I q2 It is now possible to control it precisely and almost completely independently.

[0112] As shown after time t2, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 can also be kept at zero.

[0113] [Variations] In the above embodiment, the first motor 10 and the second motor 11 to be controlled are open-winding motors, and therefore, compared to the control of a normal motor having a neutral point, twice as many (two) inverters are required for each motor. Furthermore, in the above embodiment, two open-winding motors, the first motor 10 and the second motor 11, are required. For this reason, the load on the actual arithmetic unit is high, and it may not be possible to implement the control configurations of the above embodiment together in one arithmetic unit. In such a case, for example, as in the modified example described below, the controller 25 may have to be configured using multiple physically separated arithmetic units.

[0114] Fig. 8 is a block diagram showing a control configuration of a vehicle drive system 101 according to a modified example. As shown in Fig. 8, the controller 25 of the vehicle drive system 101 is composed of a rotation state detection unit 31, a three-phase current coordinate conversion unit 32, and a calculation unit 60. The calculation unit 60 is composed of a first calculation unit 61 for controlling the first motor 10 and a second calculation unit 62 for controlling the second motor 11. That is, in the controller 25 of the vehicle drive system 101 according to the modified example, the calculation unit 60 functioning as the three-phase current coordinate conversion unit 32, the zero-phase current coordinate conversion unit 33, the torque control unit 34, the zero-phase voltage coordinate conversion unit 35, the three-phase voltage coordinate conversion unit 36, and the PWM conversion unit 37 is composed of two physically separated calculation units (61, 62).

[0115] In this way, when the controller 25 includes two physically separated arithmetic units 61, 62, these arithmetic units 61, 62 can exchange control parameters via serial communication, CAN (controller area network) communication, etc., thereby controlling the first motor 10 and the second motor 11, as in the above embodiment.

[0116] The three-phase current coordinate conversion unit 32, the zero-phase current coordinate conversion unit 33, the torque control unit 34, the zero-phase voltage coordinate conversion unit 35, the three-phase voltage coordinate conversion unit 36, and the PWM conversion unit 37 are provided in either the first arithmetic unit 61 or the second arithmetic unit 62, or in both. However, the first arithmetic unit 61 is configured to calculate only parameters related to the control of the first motor 10, and the second arithmetic unit 62 is configured to calculate only parameters related to the control of the second motor 11. The first arithmetic unit 61 is configured to acquire and calculate control parameters related to the first motor 10. Also, the second arithmetic unit 62 is configured to acquire and calculate control parameters related to the second motor 11.

[0117] For example, the first calculation unit 61 calculates the first motor current I U1 ,I V1 ,I W1 The first motor current I U1 ,I V1 ,I W1 to the second calculation unit 62. Meanwhile, the second calculation unit 62 transmits the second motor current I U2 ,I V2 ,I W2 and the second motor current I U2 ,I V2 ,I W2 to the first arithmetic unit 61. Then, the first arithmetic unit 61 and the second arithmetic unit 62 respectively calculate the first motor zero-phase current I 01 , second motor zero-phase current I 02 , rotating coordinate system zero-phase current (I 0d ,I 0q ), and the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ) is calculated.

[0118] Then, in the first calculation unit 61, the rotating coordinate system zero-phase current (I 0d ,I 0q ) is the zero-phase current command value in the rotating coordinate system (I 0d * ,I 0q* ) to be applied to the stator windings U1, V1, and W1 of the first motor 10. U1 * ,V V1 * ,V W1 * On the other hand, in the second calculation unit 62, the rotating coordinate system zero-phase current (I 0d ,I 0q ) is the zero-phase current command value in the rotating coordinate system (I 0d * ,I 0q * ) to be applied to the stator windings U2, V2, and W2 of the second motor 11. U2 * , V V2 * ,V W2 * ) to determine

[0119] Thus, the first motor current I U1 ,I V1 ,I W1 and the second motor current I U2 ,I V2 ,I W2 The first calculation unit 61 and the second calculation unit 62 mutually transmit and receive (share) the first motor zero-phase current I 01 , second motor zero-phase current I 02 , rotating coordinate system zero-phase current (I 0d ,I 0q ), and the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ) can be used to control the first motor 10 and the second motor 11 in the same manner as in the above embodiment.

[0120] In addition, in either the first arithmetic unit 61 or the second arithmetic unit 62, the first motor zero-phase current I 01 , second motor zero-phase current I 02 , rotating coordinate system zero-phase current (I 0d ,I 0q ), and the rotating coordinate system zero-phase current command value (I 0d *,I 0q * ) and transmits (shares) it to the other, the first motor 10 and the second motor 11 can be controlled in the same manner as in the above embodiment.

[0121] In this modified example, the rotation state detection unit 31 is independent of the first arithmetic unit 61 and the second arithmetic unit 62, but the rotation state detection unit 31 can also be incorporated into the first arithmetic unit 61, the second arithmetic unit 62, or both.

[0122] As described above, the open winding motor control method according to the present embodiment and the modified example is a method for controlling a motor including a first motor 10 and a second motor 11 that are open winding motors having independent stator windings of multiple phases, and a control method for controlling a motor including an open winding motor having an electrical angle θ re is a predetermined phase difference θ diff In a system (100, 101) in which the output shafts 21, 22 of the first motor 10 and the second motor 11 are connected so as to have the same rotation speed, the first motor 10 and the second motor 11 are rotated at the same rotation speed. In this open winding motor control method, a first motor current I U1 ,I V1 ,I W1 and the second motor current I, which is the current flowing through the stator windings U2, V2, and W2 of each phase of the second motor 11. U2 ,I V2 ,I W2 and the first motor current I U1 ,I V1 ,I W1 Based on this, the first motor zero-phase current I flows commonly through the stator windings U1, V1, and W1 of each phase of the first motor. 01 Calculate the second motor current I U2 ,I V2 ,I W2 Based on this, the second motor zero-phase current I 02 Furthermore, the electrical angle θ re Based on the first motor zero-phase current I 01and the second motor zero-phase current I 02 The first motor zero-phase current I 01 and the second motor zero-phase current I 02 Frequency (e.g. 3θ re The rotating coordinate system zero-phase current (I 0d ,I 0q ) is converted into the required torque T1 for the first motor 10 and the second motor 11. * ,T2 * Based on this, the rotating coordinate system zero-sequence current (I 0d ,I 0q ) is the command value for the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ) and calculate the zero-phase current in the rotating coordinate system (I 0d ,I 0q ) is the zero-phase current command value in the rotating coordinate system (I 0d * ,I 0q * The voltage (V U1 * ,V V1 * ,V W1 * ,V U2 * , V V2 * ,V W2 * ) to determine

[0123] Thus, the AC first motor zero-phase current I 01 and the second motor zero-phase current I 02 is expressed as a direct current in the zero-phase rotating coordinate system (I 0d ,I 0q ) and control the zero-sequence current in the zero-sequence rotating coordinate system, the current components for controlling torque, etc. (dq-axis current I d1 ,I q1 ,I d2 ,I q2 ) without affecting the first motor zero-phase current I 01 and the second motor zero-phase current I 02 can be flushed.

[0124] In the open winding motor control method according to the above embodiment and the modified example, the phase difference θ diff is the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is set to a value other than the specific phase difference (0 or π) that results in in-phase or anti-phase.

[0125] In this way, the phase difference θ diff By clearly setting the value other than the specific phase difference, the divergence of the calculation can be prevented, and the AC first motor zero-phase current I 01 and the second motor zero-phase current I 02 is expressed as a direct current in the zero-phase rotating coordinate system (I 0d ,I 0q ) can be particularly reliably converted into the first motor 10 and the second motor 11. That is, the stability of the control of the first motor 10 and the second motor 11 is improved.

[0126] In the open winding motor control method according to the above embodiment and modification, the electrical angle θ re The look-ahead compensation electrical angle θ re Then, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 from the rotating coordinate system zero-phase current (I 0d ,I 0q ) for electrical angle θ re As the look-ahead compensation electrical angle θ re ' is used.

[0127] Thus, the AC first motor zero-phase current I 01 and the second motor zero-phase current I 02 is expressed as a direct current in the zero-phase rotating coordinate system (I 0d ,I 0q ) when converting the look-ahead compensation electrical angle θ re Using ' reduces the effect of dead time. Therefore, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is particularly easy to control precisely.

[0128] In the open winding motor control method according to the above embodiment and the modified example, the rotating coordinate system zero-phase current (I 0d ,I 0q ) and the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ) and based on this, the rotating coordinate system zero-sequence current (I 0d ,I 0q ) to the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ) is the feedback voltage (V 0d-FB ,V 0q-FB On the other hand, the required torque T1 * ,T2 * Based on this, the dq-axis currents (I d1 ,I q1 ,I d2 ,I q2 ) command value (I d1 * ,I q1 * ,I d2 * ,I q2 * ) and calculate the electrical angle θ re , the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ), and the dq-axis currents (I d1 ,I q1 ,I d2 ,I q2 ) command value (I d1 * ,I q1 * ,I d2 * ,I q2 * ), the rotating coordinate system zero-sequence current (I 0d ,I 0q ) and the dq-axis currents (I d1 ,I q1 ,I d2 ,Iq2 ) and the decoupling voltage (V 0d-dcpl ,V 0q-dcpl ) and the feedback voltage (V 0d-FB ,V 0q-FB ) and decoupling voltage (V 0d-dcpl ,V 0q-dcpl ) and the voltage (V U1 * ,V V1 * ,V W1 * ,V U2 * , V V2 * ,V W2 * ) to determine

[0129] Thus, the AC first motor zero-phase current I 01 and the second motor zero-phase current I 02 is expressed as a direct current in the zero-phase rotating coordinate system (I 0d ,I 0q ), it is possible to perform decoupling control on the zero-phase current. By performing decoupling control on the zero-phase current, the dq-axis current I d1 ,I q1 ,I d2 ,I q2 As a result, even if such a disturbance occurs, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is the command value (I 01 * ,I 02 * Therefore, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 When a disturbance occurs while the dq-axis current I d1 ,I q1 ,I d2 ,I q2 No oscillatory components are generated in the

[0130] In the open winding motor control method according to the above embodiment and modification, the electrical angle θ re The look-ahead compensation electrical angle θ re ' and calculate the decoupling voltage (V 0d-dcpl ,V 0q-dcpl ) is calculated using the electrical angle θ re Look-ahead compensation electrical angle θ re ' is used.

[0131] In this way, in the non-interference control for the zero-phase current, the look-ahead compensation electrical angle θ re Using ' also reduces the effect of dead time. Therefore, even if a disturbance occurs, the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is particularly easy to control precisely.

[0132] In the open winding motor control method according to the above modification, the system (101) includes a first arithmetic unit 61 that controls the operation of the first motor 10 and a second arithmetic unit 62 that controls the operation of the second motor 11. The first motor current I U1 ,I V1 ,I W1 is transmitted to the second calculation unit 62, and the second motor current I U2 ,I V2 ,I W2 to the first arithmetic unit 61. In addition, the first arithmetic unit 61 and the second arithmetic unit 62 each transmit the first motor zero-phase current I 01 , second motor zero-phase current I 02 , rotating coordinate system zero-phase current (I 0d ,I 0q ), and the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ) is calculated in the first calculation unit 61. Then, the rotating coordinate system zero-phase current (I 0d ,I 0q ) is the zero-phase current command value in the rotating coordinate system (I 0d * ,I 0q* ) to be applied to the stator windings U1, V1, and W1 of the first motor 10. U1 * ,V V1 * ,V W1 * ) is determined, and in the second calculation unit 62, the rotating coordinate system zero-phase current (I 0d ,I 0q ) is the zero-phase current command value in the rotating coordinate system (I 0d * ,I 0q * ) to be applied to the stator windings U2, V2, and W2 of the second motor 11. U2 * , V V2 * ,V W2 * ) to determine

[0133] In this way, even if the arithmetic unit 60 is separated into the first arithmetic unit 61 that controls the first motor 10 and the second arithmetic unit 62 that controls the second motor 11, the AC first motor zero-phase current I 01 and the second motor zero-phase current I 02 is expressed as a direct current in the zero-phase rotating coordinate system (I 0d ,I 0q ) and control the zero-sequence current in the zero-sequence rotating coordinate system. In other words, the current components for controlling torque, etc. (dq-axis current I d1 ,I q1 ,I d2 ,I q2 ) without affecting the first motor zero-phase current I 01 and the second motor zero-phase current I 02 can be flushed.

[0134] The open winding motor control device according to the above embodiment and the modified example has a first motor 10 and a second motor 11 which are open winding motors having independent stator windings of multiple phases, and an electrical angle θ between the first motor 10 and the second motor 11 is re is a predetermined phase difference θ diffIn a system (100, 101) in which the output shafts 21, 22 of the first motor 10 and the second motor 11 are connected so as to have a rotational speed N, the first motor 10 and the second motor 11 are rotated at the same rotational speed N. This open winding motor control device controls a first motor current I U1 ,I V1 ,I W1 and the second motor current I, which is the current flowing through the stator windings U2, V2, and W2 of each phase of the second motor 11. U2 ,I V2 ,I W2 and the first motor current I U1 ,I V1 ,I W1 Based on this, the first motor zero-phase current I 01 and the second motor current I U2 ,I V2 ,I W2 Based on this, the second motor zero-phase current I 02 A zero-phase current calculation unit (32) that calculates an electrical angle θ re Based on the first motor zero-phase current I 01 and the second motor zero-phase current I 02 The first motor zero-phase current I 01 and the second motor zero-phase current I 02 The rotating coordinate zero-phase current (I 0d ,I 0q ), and a zero-phase current coordinate conversion unit 33 converts the required torque T1 * ,T2 * Based on this, the rotating coordinate system zero-sequence current (I 0d ,I 0q ) is the command value for the rotating coordinate system zero-phase current command value (I 0d * ,I 0q * ), and a zero-phase current command value calculation unit 52 that calculates the rotating coordinate system zero-phase current (I 0d ,I 0q) is the zero-phase current command value in the rotating coordinate system (I 0d * ,I 0q * The voltage (V U1 * ,V V1 * ,V W1 * ,V U2 * , V V2 * ,V W2 * and a voltage command value calculation unit 56 that determines a voltage command value.

[0135] This open winding motor control device, as described above, controls the first motor zero-phase current I 01 and the second motor zero-phase current I 02 is expressed as a direct current in the zero-phase rotating coordinate system (I 0d ,I 0q ) and controls the zero-phase current in the zero-phase rotating coordinate system, so the current components for controlling torque, etc. (dq-axis current I d1 ,I q1 ,I d2 ,I q2 ) without affecting the first motor zero-phase current I 01 and the second motor zero-phase current I 02 can be flushed.

[0136] The above describes the embodiments and modifications of the present invention. However, the configurations described in the above embodiments and modifications merely illustrate some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

[0137] For example, in the above embodiment and modified example, the vehicle drive system 100, 101 has been described as an example, but is not limited to this. re is a predetermined phase difference θ diff The present invention is also suitable for systems other than drive systems or systems other than vehicles, so long as the system has an output shaft connected so as to have the above-mentioned configuration. [Explanation of symbols]

[0138] 10: first motor, 11: second motor, 12: first inverter, 13: second inverter, 14: smoothing capacitor, 15: battery, 16: third inverter, 17: fourth inverter, 18: smoothing capacitor, 19: inverter, 21: output shaft, 22: output shaft, 25: controller, 31: rotation state detection unit, 32: three-phase current coordinate conversion unit, 33: zero-phase current coordinate conversion unit, 34: torque control unit, 35: zero-phase voltage coordinate conversion unit, 36: three-phase voltage coordinate conversion unit, 37: PWM conversion unit, 41: magnetic pole position detector, 42: magnetic pole position detector, 43: current detector, 44: current detector, 45: voltage sensor, 51: fundamental wave current command value calculation unit, 52: zero-phase current command value calculation unit, 53: look-ahead compensation unit, 54: feedback voltage calculation unit, 55: non-interfering voltage calculation unit, 56: voltage command value calculation unit, 60: calculation unit, 61: first calculation unit, 62: second calculation unit, 100: vehicle drive system, 101: vehicle drive system

Claims

1. 1. A method for controlling an open winding motor, comprising: a first motor and a second motor, each of which is an open winding motor having independent stator windings of a plurality of phases; output shafts of the first motor and the second motor are connected so that an electrical angle of the first motor and the second motor has a predetermined phase difference; and rotating the first motor and the second motor at the same rotation speed in a system, the method comprising: acquiring a first motor current which is a current flowing through the stator winding of each phase of the first motor, and a second motor current which is a current flowing through the stator winding of each phase of the second motor; calculating a first motor zero-phase current flowing in common through the stator windings of each phase of the first motor based on the first motor current; calculating a second motor zero-phase current flowing in common through the stator windings of each phase of the second motor based on the second motor current; converting the first motor zero-phase current and the second motor zero-phase current into rotating coordinate system zero-phase currents that are currents in a zero-phase rotating coordinate system that rotates at a frequency of the first motor zero-phase current and the second motor zero-phase current based on the electrical angle; Calculating a rotating coordinate system zero-phase current command value, which is a command value for the rotating coordinate system zero-phase current, based on a required torque for the first motor and the second motor; determining voltages to be applied to the stator windings of the first motor and the second motor such that the rotating coordinate system zero-phase current follows the rotating coordinate system zero-phase current command value; Open winding motor control method.

2. 2. The open winding motor control method according to claim 1, the phase difference is set to a value other than a specific phase difference at which the first motor zero-phase current and the second motor zero-phase current are in phase or in opposite phase; Open winding motor control method.

3. 3. The open winding motor control method according to claim 1, further comprising the steps of: calculating a look-ahead compensation electrical angle by compensating the electrical angle in advance based on a dead time of the system; the first motor zero-phase current and the second motor zero-phase current are converted into the rotating coordinate system zero-phase current by using the look-ahead compensation electrical angle as the electrical angle; Open winding motor control method.

4. 3. The open winding motor control method according to claim 1, further comprising the steps of: calculating a feedback voltage, which is a voltage for making the rotating coordinate system zero-phase current follow the rotating coordinate system zero-phase current command value, based on the rotating coordinate system zero-phase current and the rotating coordinate system zero-phase current command value; Calculating command values ​​for dq-axis currents of the first motor and the second motor based on the required torque; calculating a decoupling voltage that decouplings the rotating coordinate system zero-sequence current and the dq-axis currents of the first motor and the second motor based on the electrical angle, the rotating coordinate system zero-sequence current command value, and command values ​​for dq-axis currents of the first motor and the second motor; determining a voltage to be applied to the stator windings of the first motor and the second motor based on the feedback voltage and the decoupling voltage; Open winding motor control method.

5. 5. The open winding motor control method according to claim 4, calculating a look-ahead compensation electrical angle by compensating the electrical angle in advance based on a dead time of the system; In the calculation of the decoupling voltage, the look-ahead compensation electrical angle is used as the electrical angle. Open winding motor control method.

6. 3. The open winding motor control method according to claim 1, further comprising the steps of: The system includes a first computing unit that controls an operation of the first motor, and a second computing unit that controls an operation of the second motor, The first motor current acquired by the first arithmetic unit is transmitted to the second arithmetic unit; The second motor current acquired by the second arithmetic unit is transmitted to the first arithmetic unit; The first calculation unit and the second calculation unit respectively calculate the first motor zero-phase current, the second motor zero-phase current, the rotating coordinate system zero-phase current, and the rotating coordinate system zero-phase current command value; the first arithmetic unit determines a voltage to be applied to the stator winding of the first motor so that the rotating coordinate system zero-phase current follows the rotating coordinate system zero-phase current command value; the second arithmetic unit determines a voltage to be applied to the stator winding of the second motor so that the rotating coordinate system zero-phase current follows the rotating coordinate system zero-phase current command value. Open winding motor control method.

7. 1. An open winding motor control device for a system including a first motor and a second motor, each of which is an open winding motor having independent stator windings of a plurality of phases, and in which output shafts of the first motor and the second motor are connected so that an electrical angle of the first motor and the second motor has a predetermined phase difference, the open winding motor control device rotates the first motor and the second motor at the same rotation speed, a zero-phase current calculation unit that acquires a first motor current that is a current flowing through the stator windings of each phase of the first motor and a second motor current that is a current flowing through the stator windings of each phase of the second motor, and calculates a first motor zero-phase current that flows commonly through the stator windings of each phase of the first motor based on the first motor current, and calculates a second motor zero-phase current that flows commonly through the stator windings of each phase of the second motor based on the second motor current; a zero-phase current coordinate conversion unit that converts the first motor zero-phase current and the second motor zero-phase current based on the electrical angle into rotating coordinate system zero-phase currents that are currents in a zero-phase rotating coordinate system that rotates at a frequency of the first motor zero-phase current and the second motor zero-phase current; a zero-phase-sequence current command value calculation unit that calculates a rotating coordinate system zero-phase-sequence current command value that is a command value for the rotating coordinate system zero-phase current based on a required torque for the first motor and the second motor; a voltage command value calculation unit that determines voltages to be applied to the stator windings of the first motor and the second motor such that the rotating coordinate system zero-phase current follows the rotating coordinate system zero-phase current command value; An open winding motor control device comprising:

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