Rotating electric machine control device and program

Abstract

To achieve a reduction in a required voltage of a rotating electric machine and an increase in output.SOLUTION: A winding field type rotating electrical machine 40 includes a stator 50 including a stator winding 52, and a rotor 60 having a plurality of magnetic poles arranged in the circumferential direction and including a field winding 70 provided for each of the magnetic poles. A control device 30 includes a control unit that controls a stator current flowing through the stator winding 52 and a field current flowing through the field winding 70, and an acquisition unit that acquires rotation parameters indicating the rotation state of the rotor 60. The control device 30 controls the magnitude of the field current and the phase of the stator current on the basis of rotation parameters, makes the field current higher than when it is not in a high rotation state when the rotor 60 is in a high rotation state, and controls the phase of the stator current to a weakening field phase that weakens the field magnetic flux of the field winding 70.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The disclosure in this specification relates to a control device for a rotating electric machine and a program. [Background technology]

[0002] Conventionally, there has been known a wound field type rotating electric machine having a stator including a stator winding and a rotor including a field winding, as described in, for example, Patent Document 1. In this rotating electric machine, the current flowing through the stator winding and the field current flowing through the field winding are manipulated to control the torque of the rotating electric machine to a command torque. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-102111 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, it is known that interior permanent magnet rotating electrical machines (IPM motors) perform field weakening control in the high rotation range, which aims to increase reluctance torque by reducing the interlinkage magnetic flux to the stator winding (reducing back electromotive force).

[0005] On the other hand, it is also conceivable to perform field weakening in the above-described wound field type rotating electric machine. In this case, it is desirable to construct a suitable configuration for making the amount of field generated by the field winding variable.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a control device and program for a rotating electric machine that can reduce the required voltage of the rotating electric machine and improve its output. [Means for solving the problem]

[0007] The control device for a rotating electric machine according to the present invention comprises: The present invention is applied to a system including a wound field type rotating electric machine having a stator including a stator winding and a rotor having a plurality of magnetic poles arranged in a circumferential direction and including a field winding provided for each of the magnetic poles, a control unit that controls a stator current flowing through the stator winding and a field current flowing through the field winding; an acquisition unit that acquires rotation parameters that indicate a rotation state of the rotor; Equipped with The control unit controls the magnitude of the field current and the phase of the stator current based on the rotation parameters, and when the rotor is in a high rotation state where the rotation speed is higher than a predetermined rotation speed, makes the field current higher than when the rotor is not in the high rotation state, and controls the phase of the stator current to a field-weakening phase that weakens the field flux of the field winding.

[0008] In the above configuration, when the rotor is in a predetermined high rotation speed state, the field current is controlled to be higher than when the rotor is not in the high rotation speed state, and the phase of the stator current is controlled to be a field-weakening phase that weakens the field magnetic flux of the field winding. In this case, by increasing the field current, it is possible to increase the field magnetic flux while reducing the inductance of the rotor's magnetic pole center (d-axis). Furthermore, by controlling the stator current in the field-weakening phase, the interlinkage magnetic flux that links with the stator winding is reduced. This makes it possible to increase the output torque of the rotating electric machine while reducing the drive voltage applied to the stator winding. As a result, it is possible to reduce the required voltage of the rotating electric machine and improve its output. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an overall configuration diagram of a control system for a rotating electrical machine. [Figure 2] FIG. 2 is a diagram showing an inverter and its peripheral configuration. [Figure 3] FIG. [Figure 4] FIG. 4 is a diagram showing an electrical circuit provided in the rotor. [Figure 5] FIG. 2 is a functional block diagram of torque control. [Figure 6] FIG. 4 is a diagram showing the transition of fundamental current and harmonic current. [Figure 7] FIG. 4 is a diagram showing the magnetic flux generated between the stator and the rotor in a field-weakening state. [Figure 8] FIG. 10 is a diagram showing the relationship between the phase of the field current and the stator current with respect to the output torque when field weakening is performed. [Figure 9] FIG. 10 is a diagram showing the relationship between field current and required voltage. [Figure 10] FIG. 4 is a diagram showing the relationship between current phase and torque. [Figure 11] A time chart showing the changes in U-phase current, U-phase voltage, output torque, and field current. [Figure 12] A time chart showing the changes in U-phase current, U-phase voltage, output torque, and field current. [Figure 13] 4 is a time chart showing the transitions of the fundamental current and harmonic current for one phase and the transitions of the harmonic superimposed current. [Figure 14] 3A and 3B are diagrams illustrating energization control for each operating state of the rotating electric machine. [Figure 15] 4 is a flowchart showing a power supply control process. [Figure 16] 6 is a flowchart showing a processing procedure for increasing field magnetic flux in a high rotation and high load state. [Figure 17] 3A and 3B are diagrams showing the relationship between rotor rotation speed and field current, and the relationship between rotor rotation speed and stator current phase. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a control device according to the present invention will be described with reference to the drawings. The control device constitutes a control system for a rotating electric machine, and the control system is mounted on a vehicle. The rotating electric machine is a power source for running the vehicle.

[0011] 1, the control system includes a DC power supply 10, an inverter 20, a control device 30, and a rotating electric machine 40. The rotating electric machine 40 is a wound-field type synchronous machine. For example, the rotating electric machine 40, the inverter 20, and the control device 30 may be included to form an electromechanical integrated drive device, or the rotating electric machine 40, the inverter 20, and the control device 30 may each be formed by a separate component.

[0012] The rotating electric machine 40 includes a housing 41, and a stator 50 and a rotor 60 housed in the housing 41. The rotating electric machine 40 of this embodiment is an inner rotor type rotating electric machine in which the rotor 60 is disposed radially inside the stator 50.

[0013] The stator 50 includes a stator core 51 and a stator winding 52. The stator winding 52 is made of, for example, copper wire, and includes U-, V-, and W-phase windings 52U, 52V, and 52W that are arranged with an electrical angle offset of 120° from one another.

[0014] The rotor 60 includes a rotor core 61 and a field winding 70. The field winding 70 is formed by, for example, compression molding. This improves the space factor and improves the ease of assembling the field winding 70. The field winding 70 may be formed of, for example, aluminum wire. Aluminum wire has a low specific gravity and can reduce the centrifugal force when the rotor 60 rotates. Aluminum wire has lower strength and hardness than copper wire, making it suitable for compression molding. The field winding 70 is not limited to aluminum wire, and may be, for example, copper wire or CNT (carbon nanotube). The field winding does not have to be compression molded.

[0015] A rotary shaft 32 is inserted through the central hole of the rotor core 61. The rotary shaft 32 is rotatably supported by the housing 41 via a bearing .

[0016] As shown in FIG. 2, the inverter 20 includes a series connection of U-, V-, and W-phase upper-arm switches SUp, SVp, and SWp and U-, V-, and W-phase lower-arm switches SUn, SVn, and SWn. First ends of U-, V-, and W-phase windings 52U, 52V, and 52W are connected to the connection points between the U-, V-, and W-phase upper-arm switches SUp, SVp, and SWp and the U-, V-, and W-phase lower-arm switches SUn, SVn, and SWn. Second ends of the U-, V-, and W-phase windings 52U, 52V, and 52W are connected to the neutral point. That is, in this embodiment, the U-, V-, and W-phase windings 52U, 52V, and 52W are star-connected. Note that, in this embodiment, each of the switches SUp to SWn is an IGBT. A freewheel diode is connected in antiparallel to each of the switches SUp to SWn.

[0017] The collectors of the U-, V-, and W-phase upper-arm switches SUp, SVp, and SWp are connected to a positive terminal of a DC power supply 10. The emitters of the U-, V-, and W-phase lower-arm switches SUn, SVn, and SWn are connected to a negative terminal of the DC power supply 10. A smoothing capacitor 11 is connected in parallel to the DC power supply 10.

[0018] Next, the stator 50 and the rotor 60 will be described with reference to FIG.

[0019] The stator 50 and the rotor 60 are both arranged coaxially with the rotating shaft 32. In the following description, the direction in which the rotating shaft 32 extends is referred to as the axial direction, the direction extending radially from the center of the rotating shaft 32 is referred to as the radial direction, and the direction extending circumferentially around the rotating shaft 32 is referred to as the circumferential direction.

[0020] The stator core 51 is made of laminated steel plates made of a soft magnetic material and has an annular back yoke 51a and multiple teeth 51b protruding radially inward from the back yoke 51a. Multiple slots 54 are formed between adjacent teeth 51b in the circumferential direction. The stator winding 52 is formed by accommodating the phase windings of each phase in a predetermined order in each of these slots 54. For example, the stator 50 may employ a segment coil structure using multiple conductor segments. However, the structure of the stator winding 52 is arbitrary.

[0021] The rotor core 61 is made of a soft magnetic material, such as laminated steel plates. The rotor core 61 has a cylindrical portion 61a and a plurality of main pole portions 62 that protrude radially outward from the cylindrical portion 61a. In this embodiment, eight main pole portions 62 are provided at equal intervals in the circumferential direction.

[0022] The field winding 70 includes a first winding portion 71a and a second winding portion 71b. In each main pole portion 62, the first winding portion 71a is wound radially outward, and the second winding portion 71b is wound radially inward relative to the first winding portion 71a. In each main pole portion 62, the winding directions of the first winding portion 71a and the second winding portion 71b are the same. Furthermore, among circumferentially adjacent main pole portions 62, the winding directions of the winding portions 71a, 71b wound around one of the main pole portions 62 are opposite to the winding directions of the winding portions 71a, 71b wound around the other of the main pole portions 62. Therefore, the magnetization directions of circumferentially adjacent main pole portions 62 are opposite to each other. In the rotor 60, the main pole portions 62 in the rotor core 61 and the field winding 70 wound around each of the main pole portions 62 form a plurality of magnetic poles (field poles) arranged in the circumferential direction.

[0023] FIG. 4 shows an electrical circuit on the rotor 60 side, including the windings 71a and 71b wound around the main pole 62. The first winding 71a and the second winding 71b are connected in series, and a diode 80 serving as a rectifying element is connected between both ends of the series connection consisting of the windings 71a and 71b. That is, a first end of the first winding 71a is connected to the cathode of the diode 80, and a first end of the second winding 71b is connected to the second end of the first winding 71a. The anode of the diode 80 is connected to the second end of the second winding 71b. A capacitor 90 is connected in parallel to the second winding 71b. Note that the capacitor 90 may be connected in parallel to the first winding 71a instead of the second winding 71b. In FIG. 4, L1 represents the inductance of the first winding portion 71a, L2 represents the inductance of the second winding portion 71b, and C represents the capacitance of the capacitor 90.

[0024] In this embodiment, a series resonant circuit is formed by the first winding portion 71a, the capacitor 90, and the diode 80, and a parallel resonant circuit is formed by the second winding portion 71b and the capacitor 90. The first resonant frequency, which is the resonant frequency of the series resonant circuit, is designated as f1, and the second resonant frequency, which is the resonant frequency of the parallel resonant circuit, is designated as f2. The resonant frequencies f1 and f2 are expressed by the following equations (eq1) and (eq2).

[0025]

number

[0026]

number

[0027] The control device 30 generates drive signals that turn on and off each of the switches SUp to SWn that configure the inverter 20. Specifically, the control device 30 generates drive signals that turn on and off each of the arm switches SUp to SWn in order to convert the DC power output from the DC power supply 10 into AC power and supply the AC power to the U-, V-, and W-phase windings 52U, 52V, and 52W, and supplies the generated drive signals to the gates of the arm switches SUp to SWn.

[0028] The control device 30 turns on and off each of the switches SUp to SWn so that a composite current of fundamental current and harmonic current flows through each of the phase windings 52U, 52V, 52W. The fundamental current is a current that mainly generates torque in the rotating electric machine 40. The harmonic current is a current that mainly excites the field winding 70. The phase currents flowing through the phase windings 52U, 52V, 52W are shifted by 120° in electrical angle.

[0029] The control device 30 is primarily composed of a microcomputer (corresponding to a computer), which includes a CPU. The functions provided by the microcomputer can be provided by software stored in a physical memory device and a computer that executes the software, by software alone, by hardware alone, or by a combination of these. For example, when the microcomputer is provided by a hardware electronic circuit, the function can be provided by a digital circuit including multiple logic circuits or an analog circuit. For example, the microcomputer executes a program stored in a non-transitory tangible storage medium that serves as its own storage unit. The program includes, for example, a program for the processing shown in FIG. 15 (described later). Execution of the program results in the execution of a method corresponding to the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, via OTA (Over the Air) or other means.

[0030] The torque control of the rotary electric machine 40 executed by the control device 30 will be described with reference to FIG.

[0031] The two-phase conversion unit 100 converts the U, V, and W phase currents in the three-phase fixed coordinate system into a d-axis current Idr and a q-axis current Iqr in a two-phase rotating coordinate system (dq coordinate system) based on the detection value of the current sensor 21 and the electrical angle θe detected by the angle sensor 22.

[0032] The command current calculation unit 101 calculates d-axis and q-axis command currents Id* and Iq* based on the command torque Trq*. The d-axis and q-axis command currents Id* and Iq* reflect the fundamental current and the harmonic currents that excite the field winding 70. Specifically, the command current calculation unit 101 calculates the d-axis and q-axis command currents Id* and Iq* based on the command torque Trq* and map information correlating the command torque Trq* with the d-axis and q-axis command currents Id* and Iq*. The command torque Trq* is set to a larger value as the accelerator operation amount detected by the accelerator sensor 24 increases. When the rotation speed Nm of the rotor 60 increases and enters a field-weakening region, the command current calculation unit 101 sets the d-axis command current Id* so that field-weakening control is performed. The current control unit 102 increases the d-axis command current Id* in the negative direction in the field-weakening region. The rotation speed Nm of the rotor 60 may be calculated based on the detection value of the angle sensor 22.

[0033] The current control unit 102 calculates the d-axis current deviation ΔId by subtracting the d-axis current Idr from the d-axis command current Id*.The current control unit 102 calculates the q-axis current deviation ΔIq by subtracting the q-axis current Iqr from the q-axis command current Iq*.

[0034] The current control unit 102 calculates a d-axis command voltage Vd* based on the d-axis current deviation ΔId as a manipulated variable for feedback-controlling the d-axis current Idr to the d-axis command current Id*.The current control unit 102 calculates a q-axis command voltage Vq* based on the q-axis current deviation ΔIq as a manipulated variable for feedback-controlling the q-axis current Iqr to the q-axis command current Iq*.

[0035] A three-phase conversion unit 103 converts the d- and q-axis command voltages Vd, Vq in the two-phase rotating coordinate system into U-, V- and W-phase voltage command values ​​VU*, VV*, and VW* in the three-phase fixed coordinate system based on the d- and q-axis command voltages Vd*, Vq* and the electrical angle θe. The U-, V- and W-phase voltage command values ​​VU*, VV*, and VW* have waveforms with phases shifted by 120 degrees in electrical angle.

[0036] The frequencies of the harmonic components included in the U-, V-, and W-phase voltage command values ​​VU*, VV*, and VW* are set to a frequency close to the first resonant frequency f1 or a frequency close to the second resonant frequency f2, thereby increasing the excitation and reducing the amplitude of the harmonic currents, thereby reducing the torque ripple of the rotating electric machine 40.

[0037] As shown in Figure 6, the envelope of the harmonic current has half the period of the fundamental current. The envelope is shown by a dashed line in Figure 6(b). The values ​​on the vertical axis in Figure 6 indicate the relative relationship between the magnitudes of the waveforms shown in Figures 6(a) and 6(b). The timing at which the envelope reaches its peak value is shifted from the timing at which the fundamental current reaches its peak value. Specifically, the timing at which the envelope reaches its peak value is the timing at which the fundamental current reaches its fluctuation center (0).

[0038] The timing at which the envelope of the harmonic current reaches its peak value may be the timing at which the fundamental current reaches its peak value, for example.

[0039] Returning to the explanation of Fig. 5, the signal generating unit 104 generates drive signals for the upper and lower arm switches of the U, V, and W phases by three-phase modulation based on the U-, V-, and W-phase voltage command values ​​VU*, VV*, and VW* and the voltage Vdc of the DC power supply 10 detected by the voltage sensor 23. The generated drive signals are input to the gates of the respective switches. This causes the switching operation of the inverter 20 to be performed.

[0040] In this embodiment, when the rotor rotation speed of the wound-field rotating electric machine 40 is in a high rotation state where the rotor rotation speed is higher than a predetermined rotation speed, the field current flowing through the field winding 70 is made higher than when the rotor rotation speed is not in the high rotation state, and the phase of the stator current flowing through the stator winding 52 is set to a field-weakening phase that weakens the field flux of the field winding 70. Here, the high rotation state of the rotating electric machine 40 includes a rotation state in a rotation speed range where the drive voltage of the stator winding 52 reaches a saturation region, i.e., a field-weakening region. The threshold for determining the high rotation state may be, for example, ½ or ⅓ of the maximum rotation speed of the rotating electric machine 40. Furthermore, the field-weakening phase is the angle between the q axis and a current vector determined by the d-axis current Id and the q-axis current Iq in a dq coordinate system (more specifically, the angle with the counterclockwise direction from the q axis as positive), and is preferably, for example, 45° or greater. In this case, in the powering state, the range of the field weakening phase is 45 to 90°. In the regenerating state, the range of the field weakening phase is 90 to 135°. Note that the range of the field weakening phase may be set to a range other than this, for example, the lower limit of the range of the field weakening phase in the powering state may be 40° and the upper limit may be 85°.

[0041] 7 is a diagram showing the magnetic flux generated between the stator 50 and the rotor 60 in a field-weakening state. In FIG. 7, for example, a U-phase current flows through the U-phase winding (U+, U-), and as a result of this current flow, magnetic fluxes φ1 and φ2 are generated in opposite directions between the stator 50 and the rotor 60. Furthermore, a harmonic current contained in the U-phase current induces a field current in the field winding 70, and this field current generates a field magnetic flux. In FIG. 7, one main pole 62 (on the left side of the figure) of the rotor 60 is an N pole, and the other main pole 62 (on the right side of the figure) is an S pole, and the rotor 60 rotates counterclockwise.

[0042] In Fig. 7, the phase of the stator current is shifted to the advance side, resulting in a field-weakening phase. In this case, the linkage magnetic flux that links with the stator winding 52 is reduced, and the flow of the field current generates a field magnetic flux, thereby suppressing a decrease in the main magnetic flux torque. When the rotating electric machine 40 is in a high rotation state, the current flow control is performed in the state shown in Fig. 7. Control of the stator current and field current when the rotating electric machine 40 is in a high rotation state will be described in detail below.

[0043] 8 shows the relationship between the phase of the field current and the phase of the stator current with respect to the output torque when field weakening is performed in a high rotation state of the rotary electric machine 40. Note that the stator current is constant here.

[0044] As can be seen from Figure 8, when the field current is low, the degree of field weakening of the stator current in ensuring torque is relatively small, but as the field current increases, the degree of field weakening of the stator current in ensuring torque increases. It can also be seen that the output torque increases by increasing the field current and increasing the degree of field weakening of the stator current (increasing the current phase in the figure).

[0045] Next, a problem that arises when field weakening is performed in a high rotation speed state will be described.

[0046] When the field current of the field winding 70 is increased, and a command to increase the field current is issued to increase the field flux, the field current gradually increases after the command to increase the current is issued. In this case, if the phase of the stator current is set to a field-weakening phase before the field current has increased sufficiently (i.e., before the field flux increases due to excitation of the field winding 70), an increase in the drive voltage (required voltage) required to energize the stator winding 52 occurs before the field current increases. For example, when the field current is increased from a state in which the field current is zero, the stator current is initially energized in the field-weakening phase while the field current remains zero. In this case, there is a concern that the rotating electric machine 40 will temporarily enter a reluctance motor state, increasing the inductance on the d-axis and facilitating the flow of magnetic flux, which will increase the required voltage.

[0047] The relationship between the field current and the required voltage will be explained using Figure 9. In Figure 9, a1 to a4 show the relationship between the current phase and voltage when the field current is different. As examples of field current, a1 is 0 A, a2 is 10 A, a3 is 20 A, and a4 is 30 A. For a1 to a4, the effective value of the stator current is constant (250 Arms). For a11, the field current is 30 A and the effective value of the stator current is 150 Arms.

[0048] FIG. 9 shows that when field weakening is performed (for example, when the current phase is 45° or more), the required voltage of the rotating electrical machine 40 increases as the field current decreases, and this tendency becomes more pronounced as the degree of field weakening increases. On the other hand, when the field current is high, the required voltage decreases by using a field weakening phase, and this tendency becomes more pronounced as the field current increases. In other words, when the field current increases, the d-axis inductance of the rotor 60 decreases, making it difficult for magnetic flux caused by the stator current to flow through the field poles. In this case, using a field weakening phase makes it possible to lower the required voltage. Furthermore, when comparing the same field current in a field weakening state, it can be seen that when the stator current is high, the required voltage is lower than when the stator current is low.

[0049] FIG. 10 shows the relationship between current phase and torque. In FIG. 10, b1 to b4 show the relationship between current phase and torque when the field current is different. For example, b1 is 0 A, b2 is 10 A, b3 is 20 A, and b4 is 30 A. The effective value of the stator current is constant. FIG. 10 shows that in a weak field state (for example, phase -60°), the higher the field current, the higher the torque.

[0050] Therefore, in this embodiment, when the field current is increased, the field current increases in response to a command to increase the field current, and the stator current phase is not shifted and remains outside the field weakening phase until the field flux increases. Then, after the field current increases and the field flux increases, the phase of the stator current is shifted to the field weakening phase and the stator current is increased. For example, the state in which the field current reaches the command value (target value) in response to a command to increase the field current is the state in which the field flux is increasing. However, the state in which the field current increases to a predetermined value less than the command value after the command to increase the field current may also be the state in which the field flux is increasing.

[0051] Furthermore, in this embodiment, the field winding 70 is configured to be excited by a harmonic current (harmonic excitation), and in the initial state of the harmonic excitation, it is possible that the field current is not sufficiently induced by the harmonic current, and the field flux is not in a desired state. In this case, if the field flux is not in a desired state, there is a concern that the required voltage will exceed the power supply voltage when the stator current is set to a field-weakening phase, as described above.

[0052] 11 is a time chart showing the transition of one phase of the stator current (U-phase current), the transition of one phase of the drive voltage (U-phase voltage), the transition of the output torque, and the transition of the field current when a predetermined harmonic current is superimposed on the stator current (fundamental current) in a weakened field phase. The rotor rotation speed is 9000 rpm, the effective value of the stator current is 260 Arms, and the stator current phase is -60°.

[0053] In Figure 11, the stator current phase is in the field-weakening phase from the initial state immediately after the start of harmonic excitation. Also, as the U-phase current, which is a harmonic superimposed current, is energized, the field current gradually increases. In this case, the drive voltage exceeds the power supply voltage at the start of harmonic excitation and gradually decreases as the field current increases. Also, the torque gradually increases as the field current increases. However, at the start of harmonic excitation, when the field current is low, the output torque is negative.

[0054] In contrast, in Fig. 12, the amplitude and phase of the stator current are made different between the initial state immediately after the start of harmonic excitation and the subsequent excitation completion state. Note that the rotor rotation speed is 9000 rpm, and in the initial state, the effective value of the stator current is 150 Arms and the stator current phase is -30°, while in the excitation completion state, the effective value of the stator current is 260 Arms and the stator current phase is -60°.

[0055] In FIG. 12, in the initial state, the field current is increasing and sufficient field flux is not generated, so the phase of the stator current (U-phase current) is not set to a field-weakening phase (period t1 to t2 in the figure). Then, at timing t2, the phase of the stator current is shifted to a field-weakening phase, and at timing t3, the amplitude of the stator current is amplified. In this case, after a command to increase the field current is issued, the stator current is shifted to a field-weakening phase and the amplitude of the stator current is increased after the field current has increased. This prevents the U-phase voltage from exceeding the power supply voltage throughout the entire period, including the initial state in FIG. 12. Furthermore, the output torque gradually increases as the field current increases from the initial state. Note that the timing at which the phase of the stator current is shifted to a field-weakening phase and the timing at which the amplitude of the stator current is increased may be the same.

[0056] The amplitude of the fundamental current in the stator current differs between the initial state and the excitation-completed state. Figure 13(a) shows the transitions of the fundamental current and harmonic currents for one phase in the initial state (X1 in Figure 12) and the transitions of the combined current (harmonic superimposed current) of these fundamental current and harmonic current. Figure 13(b) shows the transitions of the fundamental current and harmonic currents for one phase in the excitation-completed state (X2 in Figure 12) and the transitions of the combined current (harmonic superimposed current) of these fundamental current and harmonic current. As shown in these figures, the amplitude of the fundamental current is set low in the initial state, whereas the amplitude of the fundamental current is amplified in the excitation-completed state.

[0057] In this embodiment, the operating range of the rotating electrical machine 40 is divided into a low rotation range, a high rotation / low load range, and a high rotation / high load range, and stator current control and field current control are performed separately in each of these ranges. Figure 14(a) shows the state of energization control in the low rotation range, Figure 14(b) shows the state of energization control in the high rotation / low load range, and Figure 14(c) shows the state of energization control in the high rotation / low load range.

[0058] In the low rotation range shown in Figure 14(a), the stator current phase (fundamental current phase) is set to a phase without field weakening (current phase 0°) or close to it, and when a demand for increased torque arises at low rotation speeds, the torque is increased by increasing the stator current and field current. Because the voltage drop due to back electromotive force and inductance is small in the low rotation range, even if the field flux is increased without field weakening, it can be handled within the power supply voltage. In this case, the settings of the field current and stator current should be determined based on efficiency.

[0059] In the high-speed, low-load region shown in Figure 14(b), the stator current phase (fundamental current phase) is set to a non-field-weakening phase (current phase 0°) or nearby, as in the low-speed region. Increasing the stator current and field current to increase torque in this state raises concerns that the drive voltage may exceed the power supply voltage. Therefore, the stator current phase is not set to a field-weakening phase, and the field current is not increased compared to when the rotation speed is not high (i.e., kept equal to or lower than when the rotation speed is low). Meanwhile, the amplitude of the stator current is increased compared to when the rotation speed is not high. Regarding the setting of the stator current amplitude, for example, the relationship between the command torque and the stator current command value (d- and q-axis command currents Id* and Iq*) may be defined so that, for the same command torque, the stator current command value is larger in the high-speed state than in the low-speed state. In this case, lowering the field current and reducing the interlinkage magnetic flux suppresses the back electromotive force and reduces the drive voltage. Although a small interlinkage magnetic flux results in torque limitations, it is an effective measure in the low load region.

[0060] In the high-speed, high-load region shown in Figure 14(c), the stator current phase (fundamental current phase) is set to a field-weakening phase, and the field current is increased under this condition. In other words, the field current is increased compared to when the rotation speed is not high, and the stator current phase is set to a field-weakening phase. Regarding the setting of the field current, for example, the relationship between the command torque and the field current command value should be determined so that, for the same command torque, the field current command value is larger in the high-speed state than in the low-speed state. In this case, strengthening the field flux reduces the d-axis inductance, enabling improved output, which is an effective measure in the high-load region. Furthermore, the amplitude of the stator current should be increased compared to when the rotation speed is not high. When performing field weakening, the relationship between the current phase and torque is as shown in Figure 8, so adjustments should be made to avoid excessive reduction in the main flux torque.

[0061] FIG. 15 is a flowchart showing the current supply control process in this embodiment, and this process is executed by the control device 30 at predetermined intervals.

[0062] In FIG. 15, in step S11, it is determined whether the rotor 60 is in a predetermined high rotation state. Specifically, it is determined whether the rotor rotation speed is higher than a predetermined rotation speed (e.g., 6000 rpm). At this time, the rotor rotation speed calculated based on the detection value of the angle sensor 22 is acquired (acquisition unit) as a rotation parameter indicating the rotation state of the rotor 60, and it is determined whether the rotor 60 is in a high rotation state based on the rotor rotation speed. If the rotor 60 is not in a high rotation state, the process proceeds to step S12, and if the rotor 60 is in a high rotation state, the process proceeds to step S13. In step S12, the rotating electric machine 40 is controlled in a low rotation mode. That is, the phase of the stator current is not set to a field-weakening phase, and the stator current and field current are controlled based on the command torque.

[0063] In step S13, it is determined whether the rotating electrical machine 40 is in a high-load state where the command torque is greater than a predetermined value (torque determination unit). If it is determined in step S13 that the rotating electrical machine 40 is not in a high-load state (i.e., in a high-speed, low-load state), the process proceeds to step S14, and if it is determined in step S13 that the rotating electrical machine 40 is in a high-load state (i.e., in a high-speed, high-load state), the process proceeds to step S15.

[0064] In step S14, the rotating electric machine 40 is controlled in a high-speed, low-load mode. That is, the phase of the stator current is not set to a field-weakening phase, and the field current is not increased compared to when the rotating electric machine is not in a high-speed state (that is, the field current is set to the same or lower level as when the rotating electric machine is not in a low-speed state), while the amplitude of the stator current is increased compared to when the rotating electric machine is not in a high-speed, high-load mode. In step S15, the rotating electric machine 40 is controlled in a high-speed, high-load mode. That is, the field current is increased compared to when the rotating electric machine is not in a high-speed state, and the phase of the stator current is set to a field-weakening phase. Also, the amplitude of the stator current is increased compared to when the rotating electric machine is not in a high-speed state.

[0065] 16 is a flowchart showing the procedure for increasing the field magnetic flux when the motor is in a high-speed, high-load state. This procedure is executed, for example, in step S15 of FIG.

[0066] 16, in step S21, it is determined whether or not the current situation requires an increase in field magnetic flux. When the vehicle is traveling, for example, step S21 is answered affirmatively when the rotating electric machine 40 is accelerated from a high rotation speed state and the command torque is increased. In other words, step S21 is answered affirmatively when the rotating electric machine 40 transitions from a high rotation speed, low load state to a high rotation speed, high load state. If step S21 is answered affirmatively, the process proceeds to step S22.

[0067] In step S22, a command is issued to start harmonic excitation to increase the field current. Specifically, the amplitude of the harmonic current contained in the stator current is increased. At this time, the command to start harmonic excitation is issued when the phase of the stator current is not in the field-weakening phase. In the following step S23, it is determined whether a predetermined time Ta has elapsed since the command to increase the field current was issued, and if the result of step S23 is affirmative, the process proceeds to the following step S24.

[0068] In step S24, the phase of the stator current is set to a field-weakening phase. In the following step S25, it is determined whether a predetermined time Tb (>Ta) has elapsed since the command to increase the field current was issued, and if the result of step S25 is affirmative, the process proceeds to the following step S26. In step S26, the amplitude of the fundamental wave current is amplified. Note that in the process of FIG. 16, step S25 may be omitted, and field-weakening of the stator current (step S24) and increase in the amplitude of the fundamental wave current (step S26) may be performed once the predetermined time Ta has elapsed since the command to increase the field current was issued.

[0069] According to the present embodiment described above in detail, the following excellent effects can be obtained.

[0070] When the rotor 60 is in a predetermined high rotation speed state, the field current is controlled to be higher than when the rotor 60 is not in the high rotation speed state, and the phase of the stator current is controlled to be a field-weakening phase that weakens the field flux of the field winding 70. In this case, by increasing the field current, the d-axis inductance of the rotor 60 can be reduced while the field flux can be increased. Furthermore, by controlling the stator current in the field-weakening phase, the flux linkage that links with the stator winding 52 is reduced. This makes it possible to increase the output torque of the rotating electric machine 40 while reducing the drive voltage applied to the stator winding 52. As a result, it is possible to reduce the required voltage of the rotating electric machine 40 and improve its output.

[0071] When the rotor 60 is in a predetermined high rotation speed state, in addition to the control to increase the field current and the control to make the phase of the stator current a field-weakening phase, the control to increase the amplitude of the stator current compared to when the rotor 60 is not in a high rotation speed state is configured to perform. This can further reduce the drive voltage applied to the stator winding 52 and increase the torque of the rotating electric machine 40.

[0072] When a command to increase the field current is issued to increase the field flux, the field current gradually increases after the command to increase the current is issued. In this case, if the phase of the stator current is changed to a field-weakening phase before the field current has increased sufficiently (i.e., before the field flux increases due to excitation of the field winding 70), an increase in the drive voltage of the stator winding 52 occurs before the field current increases. In this regard, because the phase of the stator current is changed to a field-weakening phase after the field flux increases in response to a command to increase the field current, it is possible to preferably achieve the effects of reducing the drive voltage applied to the stator winding 52 and increasing the torque of the rotating electric machine 40 during the period including the period immediately after the command to increase the field current.

[0073] If the phase of the stator current is changed to a field weakening phase or the stator current is increased before the field current has increased sufficiently (i.e., before the field flux has increased due to excitation of the field winding 70) after a command to increase the field current is given, an increase in the drive voltage of the stator winding 52 occurs before the increase in the field current. In this regard, by changing the phase of the stator current to a field weakening phase and increasing the stator current after the field flux has increased in response to a command to increase the field current, it is possible to preferably achieve the effects of reducing the drive voltage applied to the stator winding 52 and increasing the torque of the rotating electric machine 40 during a period including the period immediately after the command to increase the field current.

[0074] In a configuration in which a field current is induced in the field winding 70 by the harmonic current contained in the stator current, a combination of the field current and field weakening of the stator current can improve the output of the rotary electric machine 40. In this case, in particular, the harmonic current is switched to a command value corresponding to an increase in the field flux, and after the field flux is increased by the induction of the field current accompanying this switching, the phase of the stator current is set to a field weakening phase. Therefore, during the period including the period immediately after the command for the harmonic current is issued when the field current increases, the effects of reducing the drive voltage applied to the stator winding 52 and increasing the torque of the rotary electric machine 40 can be suitably achieved.

[0075] The required level of output torque differs between high load and low load conditions under high rotation speed conditions. By controlling the stator current and field current while taking this into consideration, it is possible to achieve appropriate current control according to the operating state of the rotating electrical machine 40.

[0076] (Other embodiments) The above embodiment may be modified as follows, for example.

[0077] When the rotor 60 is in a high rotation speed state, and the rotor rotation speed is relatively high, the control device 30 may increase the field current and advance the phase of the stator current compared to when the rotor rotation speed is relatively low. Specifically, when the rotor 60 is in a high rotation speed state, the control device 30 may increase the field current based on the relationship shown in Figure 17(a) when increasing the field current due to harmonic currents contained in the phase currents of each phase (e.g., step S22 of Figure 16). In Figure 17(a), when the rotor rotation speed is less than a predetermined value Nx, the field current is set to a predetermined value (lower limit) regardless of the rotor rotation speed. However, when the rotor rotation speed is equal to or greater than the predetermined value Nx, a relationship is established such that the higher the rotor rotation speed, the higher the field current.

[0078] Furthermore, when the rotor 60 is in a high rotation state, and when the phase of the stator current is set to a field-weakening phase (for example, step S24 in FIG. 16), the control device 30 may advance the phase of the stator current based on the relationship in FIG. 17(b). In FIG. 17(b), a relationship is established in which, in a rotation state in which the rotor rotation speed is less than a predetermined value Nx, the phase of the stator current is set to a predetermined value (most retarded value) regardless of the rotor rotation speed, while, in a high rotation state in which the rotor rotation speed is equal to or greater than the predetermined value Nx, the phase of the stator current is advanced as the rotor rotation speed increases.

[0079] In addition, in FIGS. 17(a) and 17(b), when the rotor 60 is in a high rotation state, the field current and stator current phases may be determined in multiple stages according to the rotor rotation speed.

[0080] The control device 30 may use the correlation between the drive voltage applied to the stator windings 52 and the rotor rotation speed to determine the rotation state of the rotor 60 based on the drive voltage of the stator windings 52. In a rotating electric machine, the higher the rotor rotation speed, the larger the drive voltage of the stator windings 52. In this case, the drive voltage of the stator windings 52 corresponds to the "rotation parameter."

[0081] Furthermore, control device 30 may calculate the rotor rotation speed based on the voltage command value of stator windings 52, and determine the rotation state of rotor 60 based on the rotor rotation speed. In this case, the rotor rotation speed calculated from the voltage command value of stator windings 52 corresponds to the "rotation parameter."

[0082] 15, in the above embodiment, the rotor 60 is compared with a predetermined rotation speed (e.g., 6000 rpm) to determine whether the rotor 60 is in a high rotation state (step S11), and if the rotor 60 is in a high rotation state, the field current is increased compared to when the rotor 60 is not in a high rotation state, and the phase of the stator current is controlled to a field-weakening phase. However, this may be modified. Specifically, instead of determining the rotor rotation state by comparing the rotor rotation speed with a predetermined rotation speed, the relationship in FIGS. 17(a) and 17(b) may be used to increase the field current compared to when the rotor 60 is not in a high rotation state, and to control the phase of the stator current to a field-weakening phase.

[0083] In the above embodiment, the command current calculation unit 101 in Fig. 5 is configured to calculate the d- and q-axis command currents to values ​​that reflect the fundamental current and the harmonic currents. However, this may be modified. For example, the d- and q-axis command currents are calculated based on the command torque so that the fundamental current is reflected, and fundamental voltage command values ​​for the U-, V-, and W-phases are calculated from the d- and q-axis command currents (command current calculation unit 101, current control unit 102, and three-phase conversion unit 103). Meanwhile, harmonic voltage command values ​​for the U-, V-, and W-phases are calculated for the harmonic currents set according to the command torque. Then, the fundamental voltage command values ​​and harmonic voltage command values ​​for the U-, V-, and W-phases are added together to calculate voltage command values ​​for the U-, V-, and W-phases, and the switching control of the inverter 20 is performed based on these voltage command values ​​for each phase.

[0084] The capacitor 90 constituting the resonant circuit may be connected in parallel to the first winding portion 71a instead of the second winding portion 71b. Also, in the resonant circuit, the anode of the diode 80 may be connected to the first winding portion 71a side of the series-connected first and second winding portions 71a, 71b, and the cathode of the diode 80 may be connected to the second winding portion 71b side.

[0085] In the rotor 60, the second winding portion 71b may be disposed closer to the stator 50 in the radial direction than the first winding portion 71a.

[0086] The rotating electric machine is not limited to an inner rotor type rotating electric machine, but may be an outer rotor type rotating electric machine, in which case the main pole portion protrudes radially inward from the rotor core.

[0087] The rotating electric machine is not limited to a star-connected rotating electric machine, but may be a delta-connected rotating electric machine.

[0088] The stator core may not have teeth.

[0089] The configuration for passing a field current through the field winding is not limited to the circuit shown in FIG. 4 , and may include, for example, a configuration including brushes electrically connected to the field winding and a power supply electrically connected to the brushes. In this case, when the rotor 60 is rotating at high speed, the control device 30 controls the field current flowing through the field winding by increasing the output voltage of the power supply electrically connected to the brushes. Note that when brushes are used, it is not necessary to pass harmonic currents through the stator winding to induce a field current.

[0090] The rotating electric machine is not limited to a rotating electric machine used as an in-vehicle main engine, but may also be, for example, a rotating electric machine used as an ISG (Integrated Starter Generator) which is a motor and generator.

[0091] The mobile body on which the control system is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship. Furthermore, the control system is not limited to a system mounted on a mobile body, but may be a stationary system.

[0092] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0093] The technical ideas extracted from the above-described embodiments will be described below. [Configuration 1] The present invention is applied to a system including a wound field type rotating electric machine (40) having a stator (50) including a stator winding (52) and a rotor (60) having a plurality of magnetic poles arranged in the circumferential direction and including a field winding (70) provided for each of the magnetic poles, a control unit that controls a stator current flowing through the stator winding and a field current flowing through the field winding; an acquisition unit that acquires rotation parameters that indicate a rotation state of the rotor; Equipped with The control unit controls the magnitude of the field current and the phase of the stator current based on the rotation parameters, and when the rotor is in a high rotation state where the rotation speed is higher than a predetermined rotation speed, the control unit increases the field current compared to when the rotor is not in the high rotation state, and controls the phase of the stator current to a field-weakening phase that weakens the field flux of the field winding. [Configuration 2] The control device for a rotating electric machine according to configuration 1, wherein, in the high rotation state, when the rotation speed of the rotor is relatively high, the control unit increases the field current and advances the phase of the stator current compared to when the rotation speed is relatively low. [Configuration 3] 3. The control device for a rotating electric machine according to configuration 1 or 2, wherein, when the rotating electric machine is in the high rotation state, the control unit increases the field current compared to when the rotating electric machine is not in the high rotation state, controls the phase of the stator current to the weakened field phase, and increases the amplitude of the stator current compared to when the rotating electric machine is not in the high rotation state. [Configuration 4] The control device for a rotating electric machine according to any one of configurations 1 to 3, wherein when the field current is increased under the high rotation state, the control unit sets the phase of the stator current to the field weakening phase after a state of field flux increase occurs in response to a command to increase the field current. [Configuration 5] The control device for a rotating electric machine according to any one of configurations 1 to 3, wherein when the field current is increased under the high rotation state, the control unit sets the phase of the stator current to the field weakening phase and increases the amplitude of the stator current after a state of increasing field magnetic flux is entered in response to a command to increase the field current. [Configuration 6] The system includes an inverter (20) electrically connected to the stator windings; The rotor has a rotor core (61) and a main pole portion (62) provided for each of the magnetic poles and protruding radially from the rotor core, the field winding has a first winding portion (71a) and a second winding portion (71b) connected in series, the first winding portion and the second winding portion are wound around the respective main pole portions, a rectifying element (80) is connected across both ends of the series-connected body, and a capacitor (90) is connected in parallel to either the first winding portion or the second winding portion; The control unit a fundamental current corresponding to a command torque of the rotary electric machine is caused to flow through the stator winding, and a harmonic current having a shorter period than the fundamental current and for inducing the field current in the field winding is caused to flow through the stator winding, and a switching operation of the inverter is performed; 6. The control device for a rotating electric machine according to any one of configurations 1 to 5, wherein, when in the high rotation state, the harmonic current is switched to a command value corresponding to an increase in field flux, and after the field flux is increased due to the induction of the field current caused by the switching, the phase of the stator current is set to the field-weakening phase. [Configuration 7] a torque determination unit that determines whether a command torque of the rotary electric machine is greater than a predetermined value; The control unit When it is determined that the motor is in the high rotation speed state and the command torque is in a high load state greater than the predetermined value, the field current is increased compared to when the motor is not in the high rotation speed state, and the phase of the stator current is set to the field weakening phase; 7. The control device for a rotating electric machine according to any one of configurations 1 to 6, wherein, when it is determined that the rotating electric machine is in the high rotation state and the command torque is in a low load state smaller than the predetermined value, the phase of the stator current is not set to the field weakening phase, and the field current is not made higher than when the rotating electric machine is not in the high rotation state, while the amplitude of the stator current is made larger than when the rotating electric machine is not in the high rotation state. [Explanation of symbols]

[0094] 30...controller, 40...rotating electric machine, 50...stator, 52...stator winding, 60...rotor, 70...field winding.

Claims

1. The present invention is applied to a system including a wound field type rotating electric machine (40) having a stator (50) including a stator winding (52) and a rotor (60) having a plurality of magnetic poles arranged in the circumferential direction and including a field winding (70) provided for each of the magnetic poles, a control unit that controls a stator current flowing through the stator winding and a field current flowing through the field winding; an acquisition unit that acquires rotation parameters that indicate a rotation state of the rotor; Equipped with The control unit controls the magnitude of the field current and the phase of the stator current based on the rotation parameters, and when the rotor is in a high rotation state where the rotation speed is higher than a predetermined rotation speed, the control unit increases the field current compared to when the rotor is not in the high rotation state and controls the phase of the stator current to a weakened field phase that weakens the field flux of the field winding, thereby reducing the drive voltage applied to the stator winding and increasing the amplitude of the stator current compared to when the rotor is not in the high rotation state.

2. The present invention is applied to a system including a wound field type rotating electric machine (40) having a stator (50) including a stator winding (52) and a rotor (60) having a plurality of magnetic poles arranged in the circumferential direction and including a field winding (70) provided for each of the magnetic poles, a control unit that controls a stator current flowing through the stator winding and a field current flowing through the field winding; an acquisition unit that acquires rotation parameters that indicate a rotation state of the rotor; Equipped with The control unit a control circuit for controlling the magnitude of the field current and the phase of the stator current based on the rotation parameters, and when the rotation speed of the rotor is in a high rotation state higher than a predetermined rotation speed, the field current is made higher than when the rotor is not in the high rotation state, and the phase of the stator current is controlled to a field-weakening phase that weakens the field flux of the field winding, thereby reducing the drive voltage applied to the stator winding; Furthermore, when the field current is increased under the high rotation state, after a state of increased field flux is reached in response to a command to increase the field current, the phase of the stator current is set to the weakening field phase and the amplitude of the stator current is increased.

3. The present invention is applied to a system including a wound field type rotating electric machine (40) having a stator (50) including a stator winding (52) and a rotor (60) having a plurality of magnetic poles arranged in the circumferential direction and including a field winding (70) provided for each of the magnetic poles, a control unit that controls a stator current flowing through the stator winding and a field current flowing through the field winding; an acquisition unit that acquires rotation parameters that indicate a rotation state of the rotor; a torque determination unit that determines whether a command torque of the rotary electric machine is greater than a predetermined value; Equipped with The control unit a control circuit for controlling the magnitude of the field current and the phase of the stator current based on the rotation parameters, and when the rotation speed of the rotor is in a high rotation state higher than a predetermined rotation speed, the field current is made higher than when the rotor is not in the high rotation state, and the phase of the stator current is controlled to a field-weakening phase that weakens the field flux of the field winding, thereby reducing the drive voltage applied to the stator winding; Furthermore, when it is determined that the motor is in the high rotation speed state and the command torque is in a high load state greater than the predetermined value, the field current is increased compared to when the motor is not in the high rotation speed state, and the phase of the stator current is set to the field weakening phase; A control device (30) for a rotating electric machine, which, when it is determined that the rotating electric machine is in the high rotation state and the command torque is in a low load state smaller than the predetermined value, does not set the phase of the stator current to the field weakening phase, does not increase the field current compared to when the rotating electric machine is not in the high rotation state, and increases the amplitude of the stator current compared to when the rotating electric machine is not in the high rotation state.

4. The control device for a rotating electric machine according to any one of claims 1 to 3, wherein, in the high rotation state, when the rotation speed of the rotor is relatively high, the control unit increases the field current and advances the phase of the stator current compared to when the rotation speed is relatively low.

5. A program executed by a computer and applied to a system including a wound field type rotating electric machine (40) having a stator (50) including a stator winding (52) and a rotor (60) having a plurality of magnetic poles arranged in a circumferential direction and including a field winding (70) provided for each of the magnetic poles, a control process for controlling a stator current flowing through the stator winding and a field current flowing through the field winding; an acquisition process for acquiring rotation parameters indicating a rotation state of the rotor; Including, The control processing controls the magnitude of the field current and the phase of the stator current based on the rotation parameters, and when the rotor is in a high rotation state where the rotation speed is higher than a predetermined rotation speed, the program increases the field current compared to when the rotor is not in the high rotation state, and controls the phase of the stator current to a weakened field phase that weakens the field flux of the field winding, thereby reducing the drive voltage applied to the stator winding and increasing the amplitude of the stator current compared to when the rotor is not in the high rotation state.

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