Charge / discharge control method and charge / discharge control device

Abstract

One embodiment of the present invention is a charge / discharge control method in which a step-up converter or a step-down converter is configured using a rotary electric machine and an inverter, and the charging or discharging of a battery is controlled. In the charge / discharge control method, a rotation angle of the rotary electric machine is detected, and a first direction, which is a direction of a magnetic flux generated by a permanent magnet, and a second direction, which is orthogonal to the first direction, are specified on the basis of the rotation angle. When the battery is charged by external equipment or when the battery is caused to discharge electricity to the external equipment, a switching element is driven so as to generate a coil magnetic flux along the second direction.

Description

Charge / discharge control method and charge / discharge control device

[0001] The present invention relates to a charge / discharge control method and a charge / discharge control device for controlling the charging or discharging of a battery.

[0002] US11171504B2 discloses a charging device that uses an inverter of a motor drive system and a three-phase AC motor as a boost converter when charging a battery from an external power source. More specifically, this charging device performs interleaving control that controls the switching operation of the inverter so that currents with different phases each of which is one-third of a cycle flow through the coils of each phase of the motor.

[0003] In interleaved control, the motor coils generate magnetic flux in sequence for each phase. For example, the U-phase coil, V-phase coil, and W-phase coil generate magnetic flux in this order during one cycle. Over one cycle, the average magnetic flux generated by the coils of the U, V, and W phases is approximately zero. For this reason, even if the motor coils are used as inductors for a boost converter, the motor does not actually rotate.

[0004] However, with interleaved control, the magnetic flux acting on the permanent magnets of the motor changes spatially and temporally, which increases losses due to eddy currents generated in the permanent magnets and makes it easy for the temperature of the motor (especially the permanent magnets) to rise.

[0005] The present invention aims to provide a charge / discharge control method and a charge / discharge control device that configure a converter using a coil of a rotating electric machine such as an electric motor and an inverter that drives the rotating electric machine, and that can suppress temperature rise of the rotating electric machine when controlling charging or discharging of a battery.

[0006] One aspect of the present invention is a charge / discharge control method for controlling charging or discharging of the battery when an external device is connected to a rotating electric machine system including a battery, a rotating electric machine that rotates due to the action of a permanent magnet magnetic flux generated by a permanent magnet and a coil magnetic flux that is a composite magnetic flux of magnetic flux generated by multiple phase coils, and an inverter that uses multiple switching elements to convert DC power output from the battery to AC power supplied to the coils. The charge / discharge control method detects a rotation angle of the rotating electric machine and identifies a first direction, which is the direction of magnetic flux generated by the permanent magnet, and a second direction, which is perpendicular to the first direction, based on the rotation angle. Then, when charging the battery with the external device or discharging the battery toward the external device, the switching elements are driven to generate coil magnetic flux along the second direction.

[0007] FIG. 1 is a block diagram showing a schematic configuration of a rotating electric machine system. FIG. 2 is a schematic circuit diagram of the rotating electric machine system. FIG. 3 is an equivalent circuit for the U phase when a boost converter is configured. FIG. 4 is a block diagram showing a configuration of a controller when a DC / DC converter is configured using an inverter and a rotating electric machine. FIG. 5 is an explanatory diagram showing coil magnetic flux generated in a rotating electric machine during charge / discharge control. FIG. 6 is a graph showing the relationship between charge output and magnet temperature when rapid charging is performed for 30 minutes. FIG. 7 is a graph showing three-phase currents, output currents before smoothing, and output currents after smoothing under charge / discharge control of a comparative example. FIG. 8 is a graph showing three-phase currents, output currents before smoothing, and output currents after smoothing under charge / discharge control of this embodiment. FIG. 9 is an explanatory diagram showing the division of control regions in a UVW coordinate system. FIG. 10 is a block diagram showing a preferred controller configuration when the average values ​​of currents flowing through the coils of each phase are equalized.

[0008] [Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0009] Fig. 1 is a block diagram showing a schematic configuration of a rotating electric machine system 100. The rotating electric machine system 100 is, for example, a vehicle drive system or a power generation system mounted on an electric vehicle such as a hybrid vehicle or an electric car. Therefore, as shown in Fig. 1, the rotating electric machine system 100 includes a battery 10, an inverter 11, a rotating electric machine 12, and a controller 13. Of these, the inverter 11 and the rotating electric machine 12 are, for example, formed substantially integrally to form a so-called electric power train 14. Furthermore, an external facility 15 may be connected to the rotating electric machine system 100.

[0010] The battery 10 is a rechargeable DC power supply. The battery 10 supplies power to drive the rotating electric machine 12. That is, when driving the rotating electric machine 12, the battery 10 supplies a DC voltage V ｄｃ On the other hand, when the rotating electrical machine 12 generates electric power, the battery 10 is charged with that electric power.

[0011] When the external equipment 15 is a quick charger or the like, the battery 10 is charged by the power supplied by the external equipment 15 via the electric power train 14. At this time, the input voltage V ＩＮ is boosted by the electric power train 14 as needed. This results in an output voltage V suitable for charging. ＯＵＴ In this embodiment, the battery 10 is charged by the voltage (DC voltage V ｄｃ ) is, for example, 800 V. The quick charger connected as the external equipment 15 is a DC power supply, and its voltage (input voltage V ＩＮ ) is, for example, 400 V or 800 V. Therefore, when a 400 V quick charger is connected, the output voltage V ＯＵＴ is boosted to 800V.

[0012] When the external equipment 15 is a device or the like that consumes power, the battery 10 can discharge and supply power to the external equipment 15 via the electric power train 14. At this time, the input voltage to the external equipment 15 is stepped down by the electric power train 14 as necessary.

[0013] The inverter 11 converts DC power output by the battery 10 into AC power and supplies it to the rotating electric machine 12. This drives the rotating electric machine 12. On the other hand, when the rotating electric machine 12 generates electric power, the inverter 11 converts the AC power generated by the rotating electric machine 12 into DC power and supplies it to the battery 10.

[0014] When an external facility 15 is connected to the rotating electric machine system 100, the inverter 11 can configure a boost converter or a buck converter together with the rotating electric machine 12. Specifically, all or part of the switching elements and free wheel diodes that configure the inverter 11 are used as elements of the boost converter or the buck converter. When the external facility 15 is a quick charger or the like, the inverter 11 configures a boost converter together with the rotating electric machine 12, and the input voltage V ＩＮ The output voltage V ＯＵＴ is applied to the battery 10. When the external equipment 15 is a device that consumes power, the inverter 11 and the rotating electric machine 12 form a step-down converter. This allows the external equipment 15 to be supplied with power from the battery 10 at the required voltage.

[0015] The rotating electric machine 12 is an electric motor or a generator. When the rotating electric machine 12 is an electric motor, the rotating electric machine system 100 is a drive system for an electric vehicle or the like that is equipped with the rotating electric machine 12. When the rotating electric machine 12 is a generator, the rotating electric machine system 100 is a power generation system for a hybrid vehicle or the like that is equipped with the rotating electric machine 12. In this embodiment, the rotating electric machine 12 is an electric motor for driving a vehicle.

[0016] The rotating electric machine 12 is an AC synchronous motor with embedded permanent magnets and has multiple phases. Therefore, the rotating electric machine 12 includes a rotor with embedded permanent magnets 40 (see FIG. 5 ) and a stator with multiple independent coils. The rotating electric machine 12 rotates due to the interaction between the magnetic flux generated by the permanent magnets (hereinafter referred to as permanent magnet magnetic flux) and the composite magnetic flux (hereinafter referred to as coil magnetic flux) generated by the multiple-phase coils. The multiple-phase coils are connected in a so-called star connection (Y connection) and have a neutral point. In this embodiment, the rotating electric machine 12 is a three-phase AC synchronous motor with embedded permanent magnets. Therefore, the rotating electric machine 12 includes a rotor with permanent magnets 40 and a stator with UVW three-phase stator coils connected in a Y connection.

[0017] When the external equipment 15 is connected to the rotating electric machine system 100, the rotating electric machine 12 and the inverter form a boost converter or a buck converter. Specifically, the coils of each phase are used as inductors of the boost converter or the buck converter. In this case, one terminal of the external equipment 15 is connected to the neutral point of the rotating electric machine 12.

[0018] The current flowing through the coils of each phase (UVW) (hereinafter referred to as the three-phase current I ＵＶＷ ), and neutral point voltage V ｎ , the rotation angle θ of the rotor (permanent magnet 40) ｒ can be detected at any timing. ＵＶＷ is detected by the current sensor 16. The neutral point voltage V ｎ is detected by the voltage sensor 17. The rotation angle θ ｒ is detected by the rotation sensor 18. The rotation angle θ ｒ is measured counterclockwise in the UVW coordinate system, with the position of the U-phase coil (U) as the reference angle (0°).

[0019] The controller 13 is a control device that comprehensively controls the operation of each part of the rotating electric machine system 100. The controller 13 is configured, for example, by one or more computers, and is programmed to cause each part to perform a predetermined operation. In this embodiment, the controller 13 is a charge / discharge control device that controls charging or discharging of the battery 10 by configuring a DC / DC converter using the inverter 11 and the rotating electric machine 12. A charge / discharge control program for operating the inverter 11 and the rotating electric machine 12 as a DC / DC converter may be provided in a form stored in a storage medium.

[0020] Specifically, the controller 13 controls the overall operation of the rotating electric machine system 100 by inputting a PWM (pulse width modulation) signal to the inverter 11. For example, the controller 13 generates a PWM signal (referred to as a rotation control PWM signal) for controlling the rotation of the rotating electric machine 12, and controls the rotation speed and torque of the rotating electric machine 12 by inputting this to the inverter 11. The controller 13 generates the rotation control PWM signal based on, for example, the amount of accelerator operation or the like.

[0021] In this embodiment, even when an external facility 15 is connected to the rotating electric machine system 100, the controller 13 inputs a PWM signal (hereinafter referred to as a converter PWM signal) to the inverter 11 to operate the electric power train 14 as a DC / DC converter. This allows the inverter 11 and the rotating electric machine 12 to function as a step-up converter or a step-down converter. The controller 13 controls the three-phase current I ＵＶＷ , neutral point voltage V ｎ , and the rotation angle θ ｒ A PWM signal for the converter is generated based on the

[0022] The external equipment 15 is equipment, a device, or the like that is provided separately from the vehicle on which the rotating electric machine system 100 is mounted. The external equipment 15 supplies power to the rotating electric machine system 100, or is supplied with power from the rotating electric machine system 100. The external equipment 15 that supplies power to the rotating electric machine system 100 is, for example, a rapid charger or other charger installed in a charging station. The external equipment 15 that receives power from the rotating electric machine system 100 is, for example, outdoor equipment. In the following, the external equipment 15 is assumed to be a rapid charger. Therefore, the external equipment 15 charges the battery 10 when connected to the rotating electric machine system 100.

[0023] Fig. 2 is a schematic circuit diagram of the rotating electric machine system 100. As shown in Fig. 2, the battery 10 includes a battery main body 21 and relay switches 22a and 22b. The inverter 11 includes a smoothing capacitor 23 and a bridge circuit 24. The rotating electric machine 12 includes a U-phase coil (U), a V-phase coil (V), and a W-phase coil (W) as multi-phase coils.

[0024] The bridge circuit 24 has legs L corresponding to the UVW phases. Ｕ , L Ｖ , L Ｗ Each leg L Ｕ , L Ｖ , L Ｗ Each of the inverters 11 consists of two arms, an upper arm and a lower arm, and the coils U, V, and W of each phase are connected between them. Each arm is formed by a switching element and a freewheeling diode. The controller 13 inputs a PWM signal to the inverter 11 to control the timing of turning on (conducting) and off (disconnecting) the switching element of each arm.

[0025] Furthermore, the rotating electrical machine system 100 includes relay switches 25, 26, and 27, a capacitor 28, and an external input / output terminal 29. These are components for connecting the external equipment 15 and the rotating electrical machine system 100.

[0026] The relay switch 25 is provided between a first terminal of the external input / output terminal 90 and one end of the battery 10, and the relay switch 26 is provided between a second terminal of the external input / output terminal 90 and the other end of the battery 10. The relay switch 27 is provided on a line connecting the first terminal of the external input / output terminal 90 and the neutral point of the rotating electric machine 12. The capacitor 28 is provided between the relay switch 27 and the neutral point of the rotating electric machine 12 so as to connect the first and second terminals of the external input / output terminal 90 in parallel.

[0027] The relay switches 25, 26, and 27 are each independently turned on / off by the controller 13. When there is no need to step up or step down the voltage, the relay switches 25 and 26 are turned on (conductive), and the relay switch 27 is turned off (disconnected). As a result, the external equipment 15 is directly connected to the battery 10 without going through the inverter 11 and the rotating electric machine 12. On the other hand, when there is a need to step up or step down the voltage, the relay switch 25 is turned off, and the relay switches 26 and 27 are turned on. As a result, the external equipment 15 is connected to the battery 10 via the rotating electric machine 12 and the inverter 11.

[0028] Figure 3 shows an equivalent circuit for the U phase when a boost converter is configured. As shown in Figure 3, when a boost converter is configured with the inverter 11 and the rotating electric machine 12, the upper arm switching element is maintained in the off state, and the lower arm switching element is controlled to be on / off. The coil of the rotating electric machine 12 (here, the U-phase coil) functions as an inductor of the boost converter. While the boost converter configuration for the U phase is shown here, the V phase and W phase are configured in the same way. The boost converters for each of the U, V, and W phases are connected in parallel to the battery 10.

[0029] Therefore, any one of the boost converters for the U, V, and W phases can be selected and used. In this embodiment, when the inverter 11 and the rotating electrical machine 12 are used as boost converters, the boost converters for all phases are used.

[0030] Furthermore, because the boost converters for each phase are connected in parallel, the on / off timing of the switching elements can be determined substantially independently for each phase. However, when current flows through the coils of each phase, torque is typically generated in the rotating electric machine 12. Therefore, when the inverter 11 and the rotating electric machine 12 are used as a boost converter, it is necessary to suppress the torque generated by the rotating electric machine 12 to an extent that the rotating electric machine 12 does not substantially rotate. The extent to which the rotating electric machine 12 does not substantially rotate refers to, for example, an extent to which an electric parking brake (so-called park lock) is not broken. In other words, when a boost converter is configured using the inverter 11 and the rotating electric machine 12 and the battery 10 is charged, at least the rotating electric machine 12 is maintained in a non-rotating state.

[0031] In addition, I １ is the output current before smoothing, and I ２ represents the output current after smoothing. When a step-down converter is configured using the inverter 11 and the rotating electric machine 12, the on / off of the upper arm switching element is controlled, and the lower arm switching element is maintained in the off state, in contrast to the step-up converter.

[0032] 4 is a block diagram showing the configuration of the controller 13 when a DC / DC converter is configured using the inverter 11 and the rotating electric machine 12. As shown in FIG. 4, the controller 13 includes a voltage controller 31, a current command generator 32, a coordinate converter 33, a current controller 34, and a PWM signal generator 35.

[0033] The voltage controller 31 detects the neutral point voltage V ｎ and the neutral point voltage V ｎ (hereinafter referred to as the neutral point voltage command V ｎ ＊ ) and based on this, the neutral point current command I ｎ ＊ More specifically, the voltage controller 31 calculates the neutral point voltage V by PI (Proportional-Integral) control, PID (Proportional-Integral-Differential) control, or the like. ｎ is the neutral point voltage command Vｎ ＊ The neutral point current command I ｎ ＊ Determine.

[0034] Neutral point current command I ｎ ＊ is the current flowing through the neutral point of the rotating electrical machine 12 (hereinafter referred to as the neutral point current I ｎ The neutral point voltage command V ｎ ＊ is set in advance by a higher-level controller (not shown) based on the specific characteristics of the external equipment 15 connected to the rotating electrical machine system 100. ｎ ＊ In any case, in this embodiment, the neutral point voltage command V ｎ ＊ is predetermined.

[0035] The current command generator 32 generates a neutral point current command I ｎ ＊ and the detected rotation angle θ ｒ Based on this, the dq axis current command I ｄｑ ＊ Calculate the dq axis current command I ｄｑ ＊ is a command for a current component in the dq-axis coordinate system that rotates together with the rotor of the rotating electrical machine 12, i.e., the d-axis current I ｄ Command for (d-axis current command I ｄ ＊ ) and q-axis current I ｑ Command for (q-axis current command I ｑ ＊ ), is a general term for

[0036] The current command generator 32 generates the dq-axis current command I so that at least the rotating electric machine 12 does not generate any torque and maintains a non-rotating state. ｄｑ ＊ The current command generator 32 determines the neutral point current I ｎ is the neutral point current command I ｎ ＊ The dq axis current command I ｄｑ＊ Furthermore, the current command generator 32 determines the dq-axis current command I ｄｑ ＊ Determine.

[0037] In order to satisfy these conditions, the current command generator 32 essentially controls the d-axis current I ｄ does not flow, and the q-axis current I ｑ flows, and the three-phase current I ＵＶＷ The rotation angle θ is set so that the phase of at least one phase current differs from the phase of the other phase current. ｒ The dq-axis current command I ｄｑ ＊ That is, the dq-axis current command I calculated by the current command generator 32 is ｄｑ ＊ When current flows through the coils (boost converter) of each phase according to the above, the three-phase current I ＵＶＷ The phase (current phase) of at least one of the three phases is different from that of the other phases, and these three phase currents I ＵＶＷ The dq axis current I ｄｑ is converted into the q-axis current I ｑ The result is that only

[0038] The coordinate converter 33 converts the detected three-phase current I ＵＶＷ and the detected rotation angle θ ｒ Based on this, the d-axis current I ｄ and q-axis current I ｑ (Hereinafter, dq-axis current I ｄｑ (called "(x,y)") is calculated.

[0039] The current controller 34 outputs the dq axis current command I ｄｑ ＊ and the dq axis current I ｄｑ Based on this, the three-phase voltage command V ＵＶＷ ＊ More specifically, the current controller 34 calculates the actual d-axis current I by PI control, PID control, etc. ｄｑ is the dq axis current command I ｄｑ ＊ The three-phase voltage command V ＵＶＷ ＊ This three-phase voltage command VＵＶＷ ＊ is the neutral point current I ｎ While maintaining the three-phase current I ＵＶＷ Therefore, the three-phase voltage command V calculated by the current controller 34 is ＵＶＷ ＊ is essentially a command (current phase command) for the phase of the current flowing through each phase. ＵＶＷ ＊ is the U-phase voltage command V Ｕ ＊ , V-phase voltage command V Ｖ ＊ , and W-phase voltage command V Ｗ ＊ is a general term for

[0040] The PWM signal generator 35 generates a DC voltage V ｄｃ and three-phase voltage command V ＵＶＷ ＊ Based on this, a PWM signal is generated that determines the timing of switching each switching element of the inverter 11 according to a predetermined PWM method such as space vector PWM control. Here, the PWM signal generated by the PWM signal generator 35 is a PWM signal for the converter. The PWM signal generator 35 can generate PWM signals independently for the switching elements of each of the UVW phases. That is, the PWM signal generator 35 generates PWM signals for the leg L. Ｕ , L Ｖ , L Ｗ A different PWM signal can be generated for each of the pulses.

[0041] In this embodiment, the PWM signal generator 35 particularly generates a first PWM signal (hereinafter referred to as PWM １ ) and the second PWM signal (hereinafter referred to as PWM ２ Two types of PWM signals are generated: １ determines the timing for switching at least one of the switching elements for each of the UVW phases. ２ determines the timing for switching the switching elements of the other phases. １ and PWM ２The timing (phase) for switching the switching elements is different for the UVW phases. １ and a phase for switching the switching element according to the PWM ２ The current phase differs from the phase in which the switching element is switched according to the current.

[0042] This PWM １ and PWM ２ By switching the switching elements of each phase by the above, the rotating electric machine 12 does not generate torque substantially, and maintains a non-rotating state, while the neutral point current I ｎ is the neutral point current command I ｎ ＊ , and furthermore, the generation of eddy currents in the permanent magnet 40 is suppressed.

[0043] The following will describe in detail the operation of the charge / discharge control that controls the charging or discharging of the battery 10 using the DC / DC converter configured by the inverter 11 and the rotating electrical machine 12 as described above.

[0044] When the inverter 11 and the rotating electric machine 12 constitute a DC / DC converter, the controller 13 detects the rotation angle θ of the rotating electric machine 12 using the rotation sensor 18. ｒ After that, the controller 13 detects (acquires) the rotation angle θ ｒ Based on this, the controller 13 identifies a first direction, which is the direction of the permanent magnet magnetic flux, and a second direction perpendicular to the first direction. In a rotating coordinate system (dq-axis coordinate system) that rotates together with the rotor, the first direction is the d-axis direction, and the second direction is the q-axis direction. Then, as described above, the controller 13 generates the dq-axis current command I ｄｑ ＊ is determined, and the PWM signal generator 35 calculates the dq axis current command I ｄｑ ＊ PWM based on １ and PWM ２ Then, the controller 13 generates this PWM １ and PWM ２By controlling the operation of the switching elements of each phase according to the above, the three-phase current I is generated so that the coil magnetic flux generated in the rotating electric machine 12 is generated along the second direction (q-axis direction). ＵＶＷ Adjust the phase of the signal.

[0045] 5 is an explanatory diagram showing the coil magnetic flux generated in the rotating electric machine 12 during charge / discharge control. When the inverter 11 and the rotating electric machine 12 are used as a DC / DC converter, the direction in which the permanent magnet 40 embedded in the rotor faces varies depending on the timing at which the rotation of the rotating electric machine 12 is stopped. For simplicity, however, it is assumed here that the N pole of the permanent magnet 40 faces the U-phase coil (U). In this case, the controller 13 controls the current (W-phase current I Ｗ ) phase by PWM １ and the current flowing through the U-phase coil (U) and the V-phase coil (V) (U-phase current I Ｕ and V-phase current I Ｖ ) phase by PWM ２ The controller 13 controls the PWM １ and PWM ２ The phase difference between the coil magnetic flux Φ and the coil magnetic flux Φ is set to 1 / 2 of the carrier wave period. As a result, the coil magnetic flux Φ is alternately generated in the positive direction of the q axis as shown in FIG. 5(A) and in the negative direction of the q axis as shown in FIG. 5(B). The coil magnetic flux Φ is the magnetic flux Φ generated by the coils of each of the U, V, and W phases. Ｕ , φ Ｖ , φ Ｗ is the resultant magnetic flux.

[0046] In this way, when the coil magnetic flux Φ is generated along the q-axis direction, the q-axis current I ｑ flows, but the d-axis current I ｄ is practically zero (even if it occurs, it is very little). ｄｑ In the situation where both of these flow, the q-axis current I ｑ Generally, the magnitude of the torque generated by the rotating electric machine 12 is determined. However, as described above, the d-axis current I ｄWhen the q-axis current I does not flow and the coil magnetic flux Φ does not include a component along the d-axis direction, the rotary electric machine 12 does not generate torque, and even if the rotary electric machine 12 generates torque, it is very small. Therefore, the rotary electric machine 12 can maintain a state where it has stopped rotating. In particular, in this embodiment, the q-axis current I ｑ generates a coil magnetic flux Φ alternately in the positive and negative directions of the q-axis, so that the time average value of the coil magnetic flux Φ is substantially zero. ｑ According to the above, the rotating electric machine 12 does not generate any torque, so the rotating electric machine 12 can maintain a state in which it has stopped rotating.

[0047] Furthermore, in FIG. 5 , for ease of explanation, the permanent magnet 40 is depicted elongated in the d-axis direction. However, in practice, the permanent magnet 40 is typically plate-shaped and thin in the d-axis direction. Therefore, when a coil magnetic flux Φ is generated along the d-axis direction, eddy currents are likely to be generated in the permanent magnet 40. The temperature of the rotating electric machine 12 (particularly the rotor) increases due to eddy current losses (hereinafter referred to as eddy current loss). However, when a coil magnetic flux Φ is generated along the q-axis direction, eddy currents are unlikely to be generated due to the actual shape of the permanent magnet 40. Therefore, by generating a coil magnetic flux Φ along the q-axis direction, eddy current loss and the temperature increase of the rotating electric machine 12 due to eddy current loss are suppressed. In other words, according to the above-described charge / discharge control, when a DC / DC converter is configured using the inverter 11 and the rotating electric machine 12, the phase of current flowing through each phase is adjusted so that a coil magnetic flux Φ is generated along the q-axis direction. This suppresses eddy current loss and the temperature increase of the rotating electric machine 12 due to eddy current loss.

[0048] FIG. 6 shows the charging output P ｃ and magnet temperature T ｍａｇ Graph 41 is a graph showing the relationship between the charging output P ｃ and magnet temperature T ｍａｇ Graph 42 shows the relationship between the charging output P ｃ and magnet temperature T ｍａｇ The charge / discharge control of the comparative example is performed with respect to the rotation angle θ ｒThat is, regardless of the orientation of the permanent magnet 40, control is performed to pass currents to the UVW phases with a phase shift of 1 / 3 cycle. Also, taking into consideration the heat resistance of the rotor and other components, the magnet temperature T ｍａｇ An upper limit value Th is previously determined for the variable .times. ...

[0049] In the charge / discharge control of the comparative example, the rotation angle θ ｒ Regardless of the magnet temperature T ｍａｇ is likely to rise, and the charging output P ｃ When the power consumption exceeds approximately 60 kW, the magnet temperature T ｍａｇ On the other hand, in the charge / discharge control of this embodiment, the three-phase current I is controlled so that only the coil magnetic flux Φ substantially along the q-axis direction is generated. ＵＶＷ Therefore, in the charge / discharge control of this embodiment, as shown in graph 42, the phase of the magnet temperature T ｍａｇ The temperature rise is suppressed, and the charging output P is up to about 200 kW. ｃ And the magnet temperature T ｍａｇ Therefore, a 30-minute rapid charge can be performed without the battery voltage reaching the upper limit value Th.

[0050] FIG. 7 shows the three-phase current I ＵＶＷ , the output current before smoothing I １ , and the smoothed output current I ２ 10 is a graph showing the three-phase current I flowing due to the charge / discharge control of the comparative example. ＵＶＷ As shown in Figure 7(A), the current ripples of each phase, which are generated by the switching of the switching elements, are also shifted by 1 / 3 of a cycle for each phase, so that the current ripples of each of the U, V, and W phases are partially cancelled out. Therefore, as shown in Figure 7(B), the output current I before smoothing, which is the sum of the output currents of each phase, １ As shown in FIG. 7C, the current ripple is suppressed. Then, as shown in FIG. 7C, the smoothed output current I ２The current ripple is suppressed to about 1 A peak-to-peak. ２ is, for example, about 200 A.

[0051] FIG. 8 shows the three-phase current I ＵＶＷ , the output current before smoothing I １ , and the smoothed output current I ２ 10 is a graph showing the three-phase current I that flows due to the charge / discharge control of this embodiment. ＵＶＷ As shown in FIG. 8A, the UV phase and the W phase have different phases. Therefore, the U-phase current I Ｕ and V-phase current I Ｖ and the W-phase current I Ｗ Since the timing (phase) of occurrence of the current ripples is different between the current ripples of the phases I and I, these are partially cancelled out. Therefore, as shown in FIG. 8B, in this embodiment, the output current I before smoothing, which is the sum of the output currents of the phases, is １ As shown in FIG. 8C, the current ripple is suppressed. Then, as shown in FIG. 8C, the smoothed output current I ２ The current ripple is suppressed to about 4 A peak-to-peak. ２ Considering that the magnet temperature T ｍａｇ This suppresses the rise in the current and reduces the current ripple.

[0052] In the above example, when the permanent magnet 40 has its N pole facing the U-phase coil (U), the controller 13 controls the W-phase by PWM. １ and UV phase is controlled by PWM. ２ By controlling the W-phase current I Ｗ and U-phase current I Ｕ and V-phase current I Ｖ However, the phase is different between the rotation angle θ ｒ If different, PWM １ , PWM ２ The combination of phases to be controlled, i.e., the combination of phase currents that cause the phases to differ, is different. ｒ Based on PWM１ Phase and PWM controlled by ２ This section describes in detail how to select the phase to be controlled.

[0053] The controller 13 calculates the rotation angle θ in the current command generator 32. ｒ Based on the above, the controller 13 determines a first coil group consisting of one or more coils (stator coils) from the coils of the multiple phases, and a second coil group consisting of a combination of coils different from the first coil group. Then, the controller 13 controls the phases having the coils belonging to the first coil group by PWM. １ and the phase having the coils belonging to the second coil group is controlled by PWM. ２ In this way, the controller 13 causes the timing of switching the switching elements to differ between the phase having the coils belonging to the first coil group and the phase having the coils belonging to the second coil group.

[0054] More specifically, the controller 13 controls the rotation angle θ ｒ Based on this, the d-axis current I ｄ The controller 13 then selects the coil of the phase for which the difference is smallest as the coil belonging to the first coil group. The controller 13 then selects the coil of the phase that does not belong to the first coil group from among the coils of the multiple phases of the rotating electric machine 12 as the coil belonging to the second coil group.

[0055] In simple terms, the controller 13 determines that the coils whose direction is closest to the q-axis (second direction) belong to the first coil group. In the example described above (see FIG. 5), the U-phase has a d-axis current I ｄ is the phase in which the d-axis current I ｄ Therefore, in the above example, the W-phase coil, which is one of the V-phase coil and the W-phase coil, is selected as the coil belonging to the first coil group, and the remaining U-phase coil and V-phase coil are selected as the coils belonging to the second coil group.

[0056] In particular, when the rotating electric machine 12 has a UVW three-phase coil, the controller 13 calculates the rotation angle θ ｒ The coils belonging to the first coil group and the second coil group can be selected based on the above.

[0057] 9 is an explanatory diagram showing division of the control region in the UVW coordinate system. As shown in FIG. 9, the UVW coordinate system is a coordinate system in which the magnetic flux φ generated by the U-phase coil is Ｕ Direction of I Ｕ ＋ Axis (0°), magnetic flux φ generated by V-phase coil Ｖ Direction of I Ｖ ＋ Axis (120°), magnetic flux φ generated by W-phase coil Ｗ Direction of I Ｗ ＋ In the UVW coordinate system, the I axis is Ｕ － The axis is an axis in the 180° direction, and I Ｖ － The axis is in the 300° direction, and the I Ｗ － The axis is in the 60° direction.

[0058] The controller 13 controls the rotation angle θ ｒ However, the coils belonging to the first coil group and the second coil group can be selected depending on which area of ​​the area (angular range) surrounded by these axes the coils belong to. Specifically, the controller 13 selects the first coil group and the second coil group according to Table 1 below.

[0059]

[0060] 1st area S １ I Ｕ ＋ Axis and I Ｗ － The second region S is the region between the axes (the region between 0° and 60°). ２ I Ｗ － Axis and I Ｖ ＋ The third region S is the region between the axes (the region between 60° and 120°). ３ I Ｖ ＋ Axis and I Ｕ － The fourth region S is the region between the axes (the region between 120° and 180°). ４ I Ｕ － Axis and I Ｗ＋ The fifth region S is the region between the axes (the region between 180° and 240°). ５ I Ｗ ＋ Axis and I Ｖ － The sixth region S is the region between the axes (the region between 240° and 300°). ６ I Ｖ － Axis and I Ｕ ＋ The area between the axes (areas of 300° or more and less than 360°). １ ~S ６ corresponds to a "sector" used when controlling the rotation of the rotating electrical machine 12 by vector control.

[0061] As in the above embodiment, it is preferable that the controller 13 drives the switching elements of each phase so as to alternately generate a coil magnetic flux Φ directed in the positive direction of the q-axis and a coil magnetic flux Φ directed in the negative direction of the q-axis. １ and PWM ２ However, if the coil magnetic flux Φ is generated along the q-axis direction, the magnet temperature T ｍａｇ The rise of is suppressed, and the PWM that achieves this １ and PWM ２ If there is a phase difference between the two, the current ripple is also suppressed. １ and PWM ２ The phase difference does not have to be half the period of the carrier wave. １ and PWM ２ The phase difference is set to 1 / 2 of the carrier wave period, and PWM １ Phase and PWM controlled by ２ When the phases of the current ripples of the phases driven by the inverter are shifted by 180°, the current ripples are most effectively suppressed.

[0062] Furthermore, when a DC / DC converter is configured using the inverter 11 and the rotating electric machine 12 as in the above embodiment, it is preferable that the controller 13 drives the switching elements of each phase so that current flows through the coils of all phases. As described above, the DC / DC converters of each phase are connected in parallel to the battery 10, so the controller 13 can charge or discharge the battery 10 without using the DC / DC converters of some phases. However, if current is made to flow through the coils of all phases and the neutral point current I ｎ When some phases are not used, the DC current loss P ｄｃ (Conduction loss) is reduced.

[0063] DC current loss P in the coil of each phase ｄｃ is expressed by the following formula (1): Ｕ , R Ｖ , and R Ｗ is the conduction resistance of the coils of each phase U, V, and W. Since the coils of each phase U, V, and W are equivalent, R Ｕ , R Ｖ , and R Ｗ The values ​​are equal.

[0064]

[0065] As can be seen from equation (1), the DC current loss P in the coil of each phase ｄｃ is most reduced when the neutral point current I ｎ Distribute evenly to each UVW phase, and Ｕ =I Ｖ =I Ｗ =I ｎ That is, the controller 13 drives the switching elements of each phase so that the average value of the current flowing through the coils of each phase is equal, thereby reducing the DC current loss P ｄｃ In this way, when the average values ​​of the currents flowing through the coils of each phase are to be equal, it is particularly preferable that the controller 13 be configured as follows.

[0066] 10 is a block diagram showing a preferred configuration of the controller 13 when the average value of the current flowing through the coils of each phase is made equal. As shown in FIG. 10, when the average value of the current flowing through the coils of each phase is made equal, the controller 13 omits the coordinate converter 33. Also, the current command generator 32 generates the neutral point current command I ｎ ＊ and rotation angle θ ｒ Based on this, the three-phase current I ＵＶＷ (hereinafter referred to as the three-phase current command I ＵＶＷ ＊ The current controller 34 is configured to calculate the three-phase current command I ＵＶＷ ＊ and the detected three-phase current I ＵＶＷ Based on this, the three-phase voltage command V ＵＶＷ ＊ In this way, the conversion to the dq-axis coordinates is omitted, and the three-phase current I ＵＶＷ is the three-phase current command I ＵＶＷ ＊ In particular, if PI control or the like is performed to follow the three-phase current I ＵＶＷ The average value of (I ｎ / 3) can be made equal.

[0067] In the above embodiment, when a DC / DC converter is configured using the inverter 11 and the rotating electric machine 12, the controller 13 can arbitrarily set or change the frequency (carrier frequency) of the carrier wave that drives the inverter 11. Therefore, when a DC / DC converter is configured using the inverter 11 and the rotating electric machine 12, it is preferable that the controller 13 drives the switching elements of each phase at a carrier frequency that is higher than the carrier frequency used to drive (rotate) the rotating electric machine 12. This is because the higher the carrier frequency, the higher the switching frequency of the switching elements of each phase, and the output current I １ , I ２ This is because the current ripple is reduced.

[0068] In the above embodiment, when a DC / DC converter is configured using the inverter 11 and the rotating electric machine 12, the controller 13 can drive the DC / DC converter of each phase in any of a continuous mode, a critical mode, and a discontinuous mode. The continuous mode is a mode in which a current flows continuously through a coil (inductor), and the current flowing through the coil is always maintained in a state greater than zero. The discontinuous mode is a mode in which the current flowing through the coil becomes zero for a certain period of time, and is discontinuous. The critical mode is a mode in which a switching element is turned on (conducted) at the timing when the current flowing through the coil becomes zero.

[0069] However, when a DC / DC converter is configured using the inverter 11 and the rotating electric machine 12, it is preferable that the controller 13 drives at least one phase of the DC / DC converter in a critical mode. That is, the controller 13 controls the PWM so that the switching element is switched from an off state to an on state when the current flowing through the coil of at least one phase among the coils of multiple phases becomes zero. １ and PWM ２ In the example described above (see FIG. 8A), the U-phase current I Ｕ and V-phase current I Ｖ When the voltage V t reaches zero, the switching elements of all phases are turned on. As a result, the U-phase and V-phase DC / DC converters are driven in critical mode, and the W-phase DC / DC converter is driven in continuous mode. In this way, driving at least one phase of the DC / DC converter in critical mode reduces the loss (switching loss) caused by the switching of the switching elements.

[0070] As described above, the charge / discharge control method according to this embodiment is a method for controlling the charge / discharge of a battery 10, a permanent magnet magnetic flux generated by the permanent magnet 40, and a magnetic flux φ generated by the coils of multiple phases (U, V, W). Ｕ , φ Ｖ , φ Ｗ and a coil magnetic flux Φ, which is a composite magnetic flux of the two coils. ｄｃWhen an external facility 15 is connected to a rotating electric machine system 100 including an inverter 11 that converts AC power into AC power to be supplied to a coil, the rotating electric machine 12 and the inverter 11 are used to form a step-up converter or a step-down converter, and the charging and discharging of the battery 10 are controlled. ｒ and the rotation angle θ ｒ Based on this, a first direction (d-axis) which is the direction of the permanent magnet magnetic flux and a second direction (q-axis) which is perpendicular to the first direction are identified, and when the battery 10 is charged by the external equipment 15 or when the battery 10 is discharged towards the external equipment 15, the switching element is driven to generate a coil magnetic flux Φ along the second direction (q-axis).

[0071] In this way, when a DC / DC converter is configured using the rotating electric machine 12 and the inverter 11, the rotation angle θ ｒ The second direction (q-axis) is determined based on the above equation, and the coil magnetic flux Φ is generated in that direction. This prevents the rotating electric machine 12 from rotating and reduces the magnet temperature T ｍａｇ This is because the coil magnetic flux Φ is generated along the second direction (q-axis), making it difficult for eddy currents to be generated in the permanent magnet 40.

[0072] In the charge / discharge control method according to the above embodiment, the timing of switching the switching elements is made different between at least one phase and the other phases, thereby generating a coil magnetic flux Φ along the second direction (q-axis).

[0073] In this way, by making the timing of switching the switching elements different between at least one phase and the other phases, the rotating electric machine 12 does not rotate and the rotating electric machine 12 (magnet temperature T ｍａｇ ) rise, and the output current I １ , I ２ The current ripple in the phases is reduced because the current ripples in each phase at least partially cancel each other out.

[0074] In the charge / discharge control method according to the above embodiment, the rotation angle θ ｒBased on this, a first coil group consisting of one or more coils and a second coil group consisting of a combination of the coils different from the first coil group are determined from the coils of the multiple phases (U, V, W).Then, the timing of switching the switching elements is made different between the phase having the coils belonging to the first coil group and the phase having the coils belonging to the second coil group.

[0075] In this way, by determining the first coil group and the second coil group and differentiating the timing of switching the switching elements in each group, it is possible to generate the coil magnetic flux Φ in the second direction (q-axis) particularly easily and accurately. Therefore, the rotating electric machine 12 is not rotated, and the rotating electric machine 12 (magnet temperature T ｍａｇ ) is easier to suppress the rise.

[0076] In the charge / discharge control method according to the above embodiment, the rotary electric machine 12 has a U-phase coil, a V-phase coil, and a W-phase coil as coils of multiple phases, and in a UVW coordinate system in which the direction of the magnetic flux generated by the U-phase coil is 0°, the direction of the magnetic flux generated by the V-phase coil is 120°, and the direction of the magnetic flux generated by the W-phase coil is 240°, the rotation angle θ ｒ The first region S is from 0° to 60° １ and the rotation angle θ ｒ The fourth region S is between 180° and 240°. ４ If the rotation angle θ is θ 1 , the W-phase coil is selected as the first coil group, and the U-phase coil and the V-phase coil are selected as the second coil group. ｒ The second region S is between 60° and 120°. ２ and the rotation angle θ ｒ The fifth region S is between 240° and 300°. ５ If the rotation angle θ is θ 1 , the U-phase coil is selected as the first coil group, and the V-phase coil and the W-phase coil are selected as the second coil group. ｒ The third region S is between 120° and 180°. ３ and the rotation angle θ ｒ The sixth region S is between 300° and 360°. ６ If so, the V-phase coil is selected for the first coil group, and the W-phase coil and the U-phase coil are selected for the second coil group.

[0077] In this way, by selecting the first coil group and the second coil group according to the region corresponding to the sector of the vector control, it is possible to generate the coil magnetic flux Φ in the second direction (q-axis) particularly easily and accurately according to the direction of the permanent magnet 40, which can be oriented in any direction. Therefore, it is possible to prevent the rotating electric machine 12 from rotating and to prevent the rotating electric machine 12 (magnet temperature T ｍａｇ ) is easier to suppress the rise.

[0078] In the charge / discharge control method according to the above embodiment, the switching element is driven to alternately generate a coil magnetic flux Φ directed in the positive direction of the second direction (q-axis) and a coil magnetic flux Φ directed in the negative direction of the second direction (q-axis).

[0079] In this way, when the coil magnetic flux Φ is alternately generated in the positive and negative directions of the q axis, the rotating electric machine 12 does not rotate, and the rotating electric machine 12 (magnet temperature T ｍａｇ ) rise, and the output current I １ , I ２ The current ripple is particularly likely to be reduced.

[0080] In the charge / discharge control method according to the above embodiment, the switching elements are driven so as to pass current through the coils of all phases (U, V, W).

[0081] In this way, when a DC / DC converter for all phases is used, the DC current loss P ｄｃ As a result, the power transmission efficiency is improved.

[0082] In the charge / discharge control method according to the above embodiment, in particular, the switching elements are driven so as to equalize the average values ​​of the currents flowing through the coils of each phase (U, V, W).

[0083] In this way, the DC current loss P in the coil of each phase ｄｃ Therefore, the power transmission efficiency is particularly improved.

[0084] In the charge / discharge control method according to the above embodiment, the switching elements are driven at a frequency higher than the frequency (carrier frequency) when driving the rotating electrical machine 12 .

[0085] In this way, when the inverter 11 is driven at a frequency higher than the frequency (carrier frequency) when driving the rotating electrical machine 12, the current ripple is reduced, and therefore the power transmission efficiency is improved.

[0086] In the charge / discharge control method according to the above embodiment, when the current flowing through the coil in at least one of the multiple phase coils (U, V, W) becomes zero, the switching element is switched from the off state to the on state.

[0087] In this way, when at least one phase of the DC / DC converter is driven in the transition mode, switching loss is reduced, resulting in improved power transmission efficiency.

[0088] The charge / discharge control device according to the above embodiment is a battery 10, a permanent magnet magnetic flux generated by the permanent magnet 40, and a magnetic flux φ generated by the coils of multiple phases (U, V, W). Ｕ , φ Ｖ , φ Ｗ and a coil magnetic flux Φ, which is a composite magnetic flux of the two coils. ｄｃ When an external facility 15 is connected to a rotating electric machine system 100 including the rotating electric machine 12 and the inverter 11, a step-up converter or a step-down converter is configured using the rotating electric machine 12 and the inverter 11, and a charge / discharge control device (controller 13) controls charging or discharging of the battery 10. The charge / discharge control device (controller 13) controls the charging or discharging of the battery 10 based on the detected rotation angle θ of the rotating electric machine 12. ｒ Based on this, a first direction (d-axis) that is the direction of the magnetic flux generated by the permanent magnet 40 and a second direction (q-axis) that is perpendicular to the first direction are identified. Then, when the battery 10 is charged by the external equipment 15 or when the battery 10 is discharged toward the external equipment 15, the switching element is driven to generate a coil magnetic flux Φ along the second direction (q-axis).

[0089] In this way, when a DC / DC converter is configured using the rotating electric machine 12 and the inverter 11, the rotation angle θ ｒThe second direction (q-axis) is determined based on the above equation, and the coil magnetic flux Φ is generated in that direction. This prevents the rotating electric machine 12 from rotating and reduces the magnet temperature T ｍａｇ This is because the coil magnetic flux Φ is generated along the second direction (q-axis), making it difficult for eddy currents to be generated in the permanent magnet 40.

[0090] Although the embodiments of the present invention have been described above, the configurations described in the above embodiments merely show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

Claims

1. A charge / discharge control method for controlling charging or discharging of a battery when an external equipment is connected to a rotating electric machine system including a battery, a rotating electric machine that rotates by the action of a coil magnetic flux, which is a composite magnetic flux of a permanent magnet magnetic flux generated by a permanent magnet and a magnetic flux generated by a coil of multiple phases, and an inverter that uses multiple switching elements to convert DC power output by the battery to AC power supplied to the coil, the charge / discharge control method comprising: detecting a rotation angle of the rotating electric machine; identifying a first direction, which is the direction of the permanent magnet magnetic flux, and a second direction perpendicular to the first direction, based on the rotation angle; and driving the switching elements to generate the coil magnetic flux along the second direction when the battery is charged by the external equipment or when the battery is discharged towards the external equipment.

2. A charge / discharge control method according to claim 1, wherein the coil magnetic flux is generated along the second direction by making the timing of switching the switching elements different between at least one phase and other phases.

3. A charge / discharge control method as described in claim 2, comprising: determining, based on the rotation angle, from the coils of a plurality of phases, a first coil group consisting of one or more of the coils, and a second coil group consisting of a combination of the coils different from the first coil group; and differentiating the timing of switching the switching elements for a phase having a coil belonging to the first coil group and a phase having a coil belonging to the second coil group.

4. A charge / discharge control method according to claim 3, wherein the rotating electric machine has a U-phase coil, a V-phase coil, and a W-phase coil as the coils of the multiple phases, and in a UVW coordinate system in which the direction of magnetic flux generated by the U-phase coil is 0°, the direction of magnetic flux generated by the V-phase coil is 120°, and the direction of magnetic flux generated by the W-phase coil is 240°, when the rotation angle is in a first region of 0° to 60° and when the rotation angle is in a fourth region of 180° to 240°, the W-phase coil is selected for the first coil group, and the U-phase coil and the V-phase coil are selected for the second coil group, when the rotation angle is in a second region of 60° to 120° and when the rotation angle is in a fifth region of 240° to 300°, the U-phase coil is selected for the first coil group, and the V-phase coil and the W-phase coil are selected for the second coil group, a charge / discharge control method comprising: selecting the V-phase coil for the first coil group, and selecting the W-phase coil and the U-phase coil for the second coil group, when the rotation angle is in a third region from 120° to 180° and when the rotation angle is in a sixth region from 300° to 360°.

5. A charge / discharge control method according to any one of claims 1 to 4, comprising driving the switching element to alternately generate the coil magnetic flux oriented in the positive direction of the second direction and the coil magnetic flux oriented in the negative direction of the second direction.

6. A charge / discharge control method according to any one of claims 1 to 4, comprising driving the switching elements so as to pass current through the coils of all phases.

7. A charge / discharge control method according to any one of claims 1 to 4, comprising driving the switching elements so as to equalize average values ​​of currents flowing through the coils of each phase.

8. A charge / discharge control method according to any one of claims 1 to 4, wherein the switching element is driven at a frequency higher than a frequency at which the rotating electric machine is driven.

9. A charge / discharge control method according to any one of claims 1 to 4, comprising switching the switching element from an off state to an on state when the current flowing through the coil in at least one of the multiple phases of the coil becomes zero.

10. A charge / discharge control device that, when an external equipment is connected to a rotating electric machine system including a battery, a rotating electric machine that rotates by the action of a coil magnetic flux, which is a composite magnetic flux of a permanent magnet magnetic flux generated by a permanent magnet and a magnetic flux generated by a coil of multiple phases, and an inverter that uses multiple switching elements to convert DC power output by the battery to AC power supplied to the coil, forms a step-up converter or a step-down converter using the rotating electric machine and the inverter, and controls charging or discharging of the battery, wherein the charge / discharge control device identifies a first direction, which is the direction of the magnetic flux generated by the permanent magnet, and a second direction perpendicular to the first direction, based on the detected rotation angle of the rotating electric machine, and drives the switching elements to generate the coil magnetic flux along the second direction when the battery is charged by the external equipment or when the battery is discharged towards the external equipment.

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