Motor control method and motor control device

Abstract

To properly perform battery warm-up control in a motor control system in which battery charging / discharging power is determined according to a request output to a polyphase motor.SOLUTION: A motor control method includes generating a switching command signal Sp by pulse width modulation based on a carrier signal C and a phase voltage command value, and controlling power to be supplied from a battery 30 to a polyphase motor 10 by operating an inverter 40 on the basis of the switching command signal Sp. In a case where it is determined that the temperature of the battery 30 is low, at least two phases of the carrier signal C are set to different values, and the switching command signal Sp is generated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor control method and a motor control device. [Background technology]

[0002] Patent Document 1 describes a warm-up control device that controls the charging and discharging of a battery mounted on a hybrid vehicle and uses the internal heat generated by the battery to raise the temperature. In particular, the battery warm-up control described in Patent Document 1 promotes the temperature rise of the battery by adopting a charging pattern that alternates between charging and discharging in a pulsed manner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-332777 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the battery warm-up control of Patent Document 1 does not take into consideration application to a motor control system that determines the battery charge / discharge power according to the required output (required driving force or required regenerative power) for a load (particularly a polyphase motor). In such a motor control system, the battery charge / discharge power is determined in consideration of the control of the polyphase motor output, so there are cases where the warm-up control that changes the battery charging pattern described above cannot be smoothly applied.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to realize more suitable warm-up control of a battery in a motor control system that determines the charge / discharge power of a battery according to the required output of a polyphase motor. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a motor control method for generating switching command signals by pulse width modulation based on a carrier signal and phase voltage command values, and operating an inverter based on the switching command signals to control power supplied from a battery to a polyphase motor. In this motor control method, when it is determined that the battery is at a low temperature, the switching command signals are generated by setting at least two phases of the carrier signal to mutually different values. [Effects of the Invention]

[0007] According to the present invention, it is possible to realize more suitable warm-up control of a battery in a motor control system that determines the charge / discharge power of a battery according to the required output of a polyphase motor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a motor control system in which a motor control method according to each embodiment is executed. [Figure 2] FIG. 2 is a diagram illustrating an embodiment of frequency control. [Figure 3] FIG. 3 is a diagram illustrating an embodiment of frequency control. [Figure 4] FIG. 4 is a diagram illustrating an embodiment of frequency control. [Figure 5] FIG. 5 is a diagram illustrating an embodiment of the transfer characteristic improvement process. [Figure 6] FIG. 6 is a diagram illustrating an embodiment of the transfer characteristic improvement process. [Figure 7] FIG. 7 is a diagram illustrating an embodiment of the transfer characteristic improvement process. [Figure 8] FIG. 8 is a diagram illustrating an embodiment of modulation factor adjustment control. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] [First embodiment] 1 is a block diagram showing the configuration of a motor control system 100 in which a motor control method according to this embodiment is executed. As shown in the figure, the motor control system 100 is mainly composed of a motor 10, a motor control device 20, a battery 30, and an inverter 40.

[0011] The motor 10 is configured, for example, by an interior permanent magnet (IPM) type three-phase synchronous motor.

[0012] The motor control device 20 calculates a phase voltage command value corresponding to the AC voltage to be applied to the motor 10 based on a torque command value determined according to a desired required output, and calculates a modulation factor M (U-phase modulation factor M) based on the phase voltage command value and the battery voltage. u , V-phase modulation rate M v , W-phase modulation rate M w ) is calculated.

[0013] The motor control device 20 also generates a PWM (Pulse Width Modulation) signal S from a modulation factor M and a carrier signal (carrier C) generated by a predetermined carrier generator. p More specifically, the motor control device 20 generates the modulation factor M u ,M v ,M w and the carrier C of each phase u ,C v ,C w The magnitude relationship between and is compared, and the on / off pattern (duty pattern) of each switching element SW is determined based on the comparison result, and this is output as the PWM signal S p In particular, the motor control device 20 determines the U-phase modulation rate M u is U-phase carrier C u When the value of the switching element SW corresponding to the U phase is larger than uIf the V-phase duty pattern and the W-phase duty pattern are set in the same way, the upper arm is turned on and the lower arm is turned off when the V-phase duty pattern and the W-phase duty pattern are set in the same way.

[0014] Furthermore, the motor control device 20 of this embodiment uses the temperature detection value of the battery 30 (hereinafter simply referred to as the “battery temperature T B In the basic control mode, the motor control device 20 uses a basic carrier C1 (to be described later) to generate a PWM signal S p On the other hand, in the warm-up control mode, the motor control device 20 generates the PWM signal S using a warm-up carrier C2 (described later) that is different from the basic carrier C1. p The basic control mode and the warm-up control mode will be described in detail later.

[0015] The motor control device 20 is realized by a computer that includes a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and input / output interface (I / O interface) and is programmed to be able to execute the above-mentioned components. The motor control device 20 can also be configured by multiple computer hardware components that execute each process in a distributed manner.

[0016] The inverter 40 includes a smoothing capacitor 42 connected in parallel to the battery 30, and each of the switching elements SW described above. Furthermore, the inverter 40 controls each of the switching elements SW in accordance with a switching pattern defined by a PWM signal generated by the motor control device 20. u The device is provided with a driving circuit (not shown) for driving the device.

[0017] The battery 30 is configured by an in-vehicle secondary battery such as a lithium ion secondary battery.

[0018] The processing by the motor control device 20 will be described in detail below. B is equal to or greater than a predetermined threshold temperature, the basic control mode is executed, while the battery temperature T B If the battery temperature T is lower than the threshold temperature, the warm-up control mode is executed. B It is determined appropriately from the viewpoint of determining whether the value of the temperature is decreasing.

[0019] The basic control mode is a control mode in which a carrier C is set to determine a duty pattern according to a phase voltage command value based on a torque command value of the motor 10, taking into consideration energy efficiency (electricity cost). In particular, in the basic control mode, the PWM signal S is generated using a basic carrier C1 in which the phases of the respective phases are set to the same value. p Generate.

[0020] On the other hand, the warm-up control mode is a control mode that sets a carrier C that determines a duty pattern that promotes the temperature rise of the battery 30 while satisfying the torque command value of the motor 10 in a low-temperature environment, etc. In particular, in the warm-up control mode, a warm-up carrier C2 that is different from the basic carrier C1 is used to generate the PWM signal S p Generate.

[0021] Here, the warm-up carrier C2 is set to have different values ​​for at least two of the phases. In particular, in this embodiment, as shown in FIG. 1, the U-phase carrier C2 u The phase of the V-phase carrier C2 v and W-phase carrier C2 w The phases are determined to be shifted by 180° with respect to each other.

[0022] As a result, in the warm-up control mode, the warm-up carrier C2 with a phase difference between each phase is used to control the switching elements SW of each phase. u ,SW v ,SW w Therefore, each switching element SW u ,SW v ,SW wIn the basic control mode, a current amplitude (hereinafter also referred to as "ripple current I") larger than that in the basic control mode can be generated in the bus bar 44 electrically connecting the inverter 40 and the smoothing capacitor 42. Then, this ripple current I is transmitted to the battery 30 via the electrical connection 50 between the inverter 40 and the battery 30, thereby inducing a ripple current I' having the same frequency component as the carrier frequency f in the battery 30. As a result, the current flowing through the battery 30 (the amount of heat generated) increases due to the generation of the ripple current I', and the temperature rise is promoted.

[0023] For the sake of simplicity, in FIG. 1, the modulation factor M of each phase is assumed to be when the motor 10 is stopped. u ,M v ,M w On the other hand, when the motor is driven, the modulation factor M of each phase is synchronized with the driving conditions (phase voltage command value, motor induced voltage, etc.). u ,M v ,M w changes, but the above control logic is still applicable in this case.

[0024] The effects of the motor control method of this embodiment described above will now be summarized.

[0025] In the motor control method of this embodiment, a switching command signal (PWM signal S) is generated by pulse width modulation based on a carrier signal (carrier C) and a phase voltage command value. p ) and generates the PWM signal S p In particular, in this motor control method, when it is determined that the battery 30 is at a low temperature, the inverter 40 is operated to control the power supplied from the battery 30 to the polyphase motor (motor 10). In particular, in this motor control method, when it is determined that the battery 30 is at a low temperature, the PWM signal S is generated based on a warm-up carrier signal (warm-up carrier C2) in which at least two phases of the carrier C are set to mutually different values. p Generate.

[0026] As a result, the PWM signal S is generated based on the phase voltage command value corresponding to the required output of the motor 10. pand supplies power from the battery 30 to the motor 10, the simple method of adjusting the phase of the carrier C can increase the self-heating of the battery 30 and promote warm-up. As a result, in situations where warm-up is required, such as in low-temperature environments, it is possible to increase the temperature-raising effect of the battery 30 while maintaining control over the motor 10, thereby improving the charge and discharge characteristics.

[0027] In particular, in this embodiment, the phase voltage command value corresponding to the required output of the motor 10 is maintained, while the phase of the carrier C is adjusted to increase the current flowing to the battery 30, thereby promoting temperature rise. Therefore, it is possible to raise the temperature of the battery 30 while minimizing the impact on the drive control of the motor 10.

[0028] More specifically, in this embodiment, the battery temperature T B When the temperature is equal to or higher than a predetermined threshold temperature, the PWM signal S is generated from the basic carrier signal (basic carrier C1) in which the phases of the respective phases are set to be the same. p On the other hand, the basic control mode is executed to generate the battery temperature T B When the temperature is lower than the predetermined threshold temperature, the PWM signal S is generated from the warm-up carrier signal (warm-up carrier C2) in which at least two phases are set to different values. p The warm-up control mode is executed to generate the

[0029] This allows the carrier C to be appropriately selected between the basic carrier C1 and the warm-up carrier C2 depending on whether or not warm-up of the battery 30 is required. Therefore, a specific control logic is realized that enables the basic carrier C1, which is more suitable for controlling the drive of the motor 10, to be used in situations where warm-up of the battery 30 is not required, while the warm-up carrier C2, which is more suitable for raising the temperature of the battery 30, to be used in situations where warm-up is required.

[0030] Furthermore, this embodiment provides a motor control device 20 suitable for executing the above motor control method.

[0031] In this embodiment, the U-phase carrier C2 in the warm-up carrier C2 u The phase of the V-phase carrier C2 v and W-phase carrier C2 w However, the example in which the carriers C2 for the warm-up are shifted by 180° with respect to each phase of the carriers C2 for the warm-up u ,C2 v ,C2 w The specific aspects of the phase setting are not limited to this, and can be adjusted appropriately taking into consideration the balance between the effect on the drive control of the motor 10 and the magnitude of the effect on the temperature rise of the battery 30.

[0032] [Second embodiment] The second embodiment will be described below. Note that in the following embodiments, the description of the same configuration as that described in the previous embodiment will be omitted as appropriate.

[0033] The motor control device 20 of this embodiment performs control (hereinafter also referred to as "frequency control") to further promote the temperature rise of the battery 30 by changing the carrier frequency f in addition to the carrier phase described above between the basic control mode and the warm-up control mode.

[0034] Specifically, motor control device 20 sets carrier frequency f (i.e., the frequency of basic carrier C1) in basic control mode to fundamental frequency f1. Note that fundamental frequency f1 is a frequency that is appropriately determined taking into consideration factors such as reducing switching loss when driving motor 10.

[0035] Meanwhile, the motor control device 20 sets the carrier frequency f during the warm-up control mode (i.e., the frequency of the warm-up carrier C2) to a warm-up frequency f2 that is different from the fundamental frequency f1. The warm-up frequency f2 is determined appropriately from the viewpoint of further enhancing the temperature rise effect of the battery 30 during warm-up.

[0036] In particular, in this embodiment, the transfer characteristic T from the ripple current I generated in the bus bar 44 to the ripple current I′ induced in the battery 30 is I´ / IThe warm-up frequency f2 is determined taking into consideration (f), as will be explained in detail below.

[0037] FIG. 2A is a diagram showing the main part of the circuit configuration between the battery 30 and the inverter 40 in this embodiment.

[0038] As already explained, the ripple current I' generated in the battery 30 is induced by the ripple current I generated in the bus bar 44 of the inverter 40. Therefore, the transfer characteristic T from the ripple current I to the ripple current I' is I´ / I (f) depends on the configuration of the electrical connection 50 between the bus bar 44 and the battery 30.

[0039] More specifically, assuming the circuit configuration shown in FIG. 2(A), the transfer characteristic T I´ / I (f) is determined by the capacitance of the smoothing capacitor 42 and the parasitic inductance L of the electrical connection 50.

[0040] FIG. 2(B) shows the transfer characteristic T I´ / I FIG.

[0041] As shown in the figure, the transfer characteristic T I´ / I (f) shows the primary low-pass filter characteristics based on the ripple current I of the bus bar 44. Therefore, assuming the above circuit configuration, the lower the carrier frequency f, the shorter the transfer characteristic T I´ / I In other words, the lower the carrier frequency f, the larger the ripple current I' induced for the same ripple current I.

[0042] For this reason, in this embodiment, the warm-up frequency f2 is set lower than the fundamental frequency f1 (first frequency control), which increases the ripple current I' during the warm-up control mode, thereby increasing the amount of self-heat generation of the battery 30.

[0043] According to the motor control method of the present embodiment described above, in the basic control mode, the carrier frequency f of the basic carrier C1 is set to a predetermined basic frequency f1, while in the warm-up control mode, the carrier frequency f of the warm-up carrier signal (warm-up carrier C2) is set to a warm-up frequency f2 that is different from the basic frequency f1.

[0044] This allows the carrier frequency f to be switched between values ​​suitable for each mode during non-warm-up (basic control mode) and warm-up (warm-up control mode). More specifically, during non-warm-up, the PWM signal S suitable for driving the motor 10 is p , and the PWM signal S p A specific control logic for generating the

[0045] In particular, in this embodiment, the warm-up frequency f2 is set lower than the fundamental frequency f1.

[0046] As a result, assuming a specific circuit configuration (FIG. 2A) between the battery 30 and the inverter 40, a specific control logic for further enhancing the temperature rise effect of the battery 30 during warm-up is realized.

[0047] [Third embodiment] In this embodiment, an example will be described in which motor control device 20 executes second frequency control. More specifically, in the second frequency control, warm-up frequency f2 is set so that the effective value of the current flowing through battery 30 is greater than the effective value of the phase current of motor 10. The effective values ​​of the current flowing through battery 30 and the phase current of motor 10 can each be calculated from values ​​detected by current sensors (not shown).

[0048] This makes it possible to further increase the ripple current I' in the warm-up control mode, thereby further enhancing the effect of raising the temperature of the battery 30.

[0049] [Fourth embodiment] In this embodiment, an example will be described in which the motor control device 20 executes the third frequency control. In particular, in this embodiment, in the same circuit configuration (FIG. 3A) as the circuit configuration (FIG. 2A) described in the second embodiment, the internal resistance R of the battery 30 becomes equal to or less than a certain value (more specifically, the battery temperature T B transfer characteristic T I´ / I The warm-up frequency f2 is determined taking into consideration (f).

[0050] Figure 3(B) shows the transfer characteristic T for a specific scene, assuming the circuit configuration of Figure 3(A). I´ / I FIG.

[0051] During the warm-up control mode, when the internal resistance R of the battery 30 is particularly low, a resonance phenomenon occurs between the capacitance of the smoothing capacitor 42 and the parasitic inductance L of the electrical connection 50. Therefore, as shown in FIG. 3(B), the transfer characteristic T I´ / I (f) shows a profile having a peak at a specific frequency (resonant frequency). Therefore, in this scenario, by setting the warm-up frequency f2 to be the same as the resonant frequency or a frequency in the vicinity thereof, the temperature rise effect of the battery 30 can be further improved.

[0052] The resonance frequency is calculated in advance from the known capacitance and parasitic inductance L of the smoothing capacitor 42 and stored, and is referred to by the motor control device 20 as appropriate.

[0053] As described above, in this embodiment, the inverter 40 includes the smoothing capacitor 42 connected in parallel to the battery 30. In the warm-up control mode, the warm-up frequency f2 is set to be substantially the same as the resonant frequency in a resonant system including the smoothing capacitor 42 and the parasitic inductance L generated by the electrical connection 50 between the battery 30 and the smoothing capacitor 42.

[0054] As a result, the transfer characteristic T I´ / IConsidering (f), it is possible to determine the warm-up frequency f2 that suitably promotes the self-heating of the battery 30. As a result, it is possible to further improve the effect of raising the temperature of the battery 30 during the warm-up control mode.

[0055] [Fifth embodiment] In this embodiment, a fourth aspect of frequency control will be described.

[0056] 4(A) is a diagram showing the main parts of the circuit configuration between the battery 30 and the inverter 40 in this embodiment. As shown in the figure, in the circuit configuration of this embodiment, a resonance characteristic adjustment capacitor 60 is provided between the smoothing capacitor 42 of the inverter 40 and the battery 30, and connected in parallel therewith. That is, the circuit configuration of FIG. 4(A) differs from the circuit configuration of FIG. 3(A) in that the resonance characteristic adjustment capacitor 60 is provided.

[0057] By providing the resonance characteristic adjusting capacitor 60 in this way, the characteristics of the electrical connection 50 from the inverter 40 to the battery 30 are changed. Therefore, the characteristics of the resonance system are adjusted for the circuit configuration of FIG. 3(A) to change the transfer characteristic T I´ / I The profile (peak frequency, peak position and / or peak width) of (f) can be varied.

[0058] Figure 4(B) shows the transfer characteristic T I´ / I As shown in the figure, the transfer characteristic T I´ / I In (f), the transfer characteristic T I´ / I Compared to (f), the peak width is narrower and the peak height is greater. Therefore, by setting the warm-up frequency f2 equal to the resonant frequency, the value of the ripple current I' per ripple current I becomes larger, and the temperature rise effect of the battery 30 can be further improved.

[0059] As described above, in this embodiment, the resonance characteristic adjusting capacitor 60 connected in parallel to the battery 30 is provided at the electrical connection 50 between the battery 30 and the smoothing capacitor 42 .

[0060] This changes the characteristics of the resonant system in the circuit configuration including the inverter 40 and the battery 30, and the transfer characteristic T I´ / I In particular, in this embodiment, the profile of the transfer characteristic T I´ / I The profile (f) is adjusted to have a higher value at the frequency where the frequency f2 for warming up reaches its peak (i.e., the resonant frequency). Therefore, by matching the warming-up frequency f2 with the resonant frequency, the temperature rise effect of the battery 30 can be further improved.

[0061] In particular, with the control of this embodiment, even in a situation where the internal resistance of the battery 30 is low, such as in an extremely low temperature environment, it is possible to appropriately encourage the self-heating of the battery 30 and achieve a sufficient temperature increase effect.

[0062] In this embodiment, an example has been described in which the resonance characteristics (transfer characteristic profile) is changed by connecting the resonance characteristic adjustment capacitor 60 in parallel to the battery 30, assuming the circuit configuration shown in Fig. 4(A). However, the specific configuration for changing the resonance characteristics is not limited to this, and can be changed as appropriate depending on the assumed circuit configuration, etc.

[0063] [Sixth embodiment] In this embodiment, a fifth aspect of frequency control will be described.

[0064] Specifically, in this embodiment, the current of the battery 30 corresponding to the change in the carrier frequency f during the warm-up control mode is measured, and a process (frequency search process) is executed to determine the warm-up frequency f2 according to the measurement result.

[0065] More specifically, in the frequency search process, the carrier frequency f is swept within a predetermined range, starting from a predetermined timing such as the start of the warm-up control mode. Then, the frequency at which the current of the battery 30 is maximized within the swept range is identified, and the identified frequency is set as the warm-up frequency f2. Furthermore, the frequency search process is executed at predetermined time intervals, and the warm-up frequency f2 is updated as appropriate.

[0066] This makes it possible to determine the warm-up frequency f2 that can induce a high ripple current I' appropriately in accordance with the actual current behavior of the battery 30 during the warm-up control mode.

[0067] According to the motor control method of the present embodiment described above, in the warm-up control mode, a frequency search process is executed to search for and set the warm-up frequency f2 at predetermined time intervals. In particular, in the frequency search process, the carrier frequency f is changed within a predetermined search range, the current of the battery 30 is observed, and the frequency at which the current of the battery 30 is highest within the search range is set as the warm-up frequency f2.

[0068] This allows the battery temperature T B Even if the frequency at which a high ripple current I' can be realized changes due to a change in the frequency at which the ripple current I' can be maximized, the frequency at which the ripple current I' can be maximized can be appropriately identified and set as the warm-up frequency f2. This further improves the temperature increase effect of the battery 30 in the warm-up control mode.

[0069] As explained in the fourth embodiment, the transfer characteristic T I´ / I When (f) has a profile with a peak at the resonance frequency, a frequency range including the peak may be specified in advance to perform the frequency search process. This allows the transfer characteristic T I´ / I In particular, as explained in the fifth embodiment, the frequency at which the transfer characteristic T I´ / I If the peak width of (f) is relatively narrow (relatively sharp), a frequency search process is performed to obtain the transfer characteristic T I´ / I By more reliably identifying the frequency at which (f) peaks, it is possible to more reliably prevent a significant decrease in ripple current I' (a decrease in the temperature-raising effect of battery 30) caused by setting warm-up frequency f2 at a frequency that is different from the frequency.

[0070] [Seventh embodiment] In this embodiment, the motor control device 20 has a transfer characteristic T I´ / I An example of executing control to further improve (f) (hereinafter referred to as "transfer characteristic improvement processing") will be described.

[0071] FIG. 5A shows the transfer characteristic T from the ripple current I to the ripple current I′ in this embodiment. I´ / I 1 is a diagram showing a circuit configuration that determines (f). As shown in the figure, in the circuit configuration of this embodiment, the smoothing capacitor 42 of the inverter 40 is composed of two capacitor elements 42a, 42b connected in parallel to the battery 30. Of these two, the capacitor element 42a, which is provided on the bus bar 44 side, is provided with a switch 70. The motor control device 20 controls the on / off operation of the switch 70, thereby switching the electrical connection between the capacitor element 42a and the battery 30 between a connected state (on state) and a disconnected state (off state).

[0072] In particular, in this embodiment, the motor control device 20 turns on the switch 70 when the temperature rise rate of the battery 30 is equal to or greater than a predetermined threshold rate. On the other hand, when the temperature rise rate of the battery 30 is less than the threshold rate, the motor control device 20 turns off the switch 70 (first transfer characteristic improvement process). The temperature rise rate of the battery 30 can be determined, for example, from changes over time in the temperature sensor value.

[0073] FIG. 5B shows the transfer characteristic T I´ / I FIG.

[0074] As shown in the figure, when the switch 70 is turned off and the capacitor element 42a is electrically disconnected from the battery 30, the transfer characteristic T I´ / I Therefore, if the temperature rise rate of the battery 30 does not reach the desired rate during warm-up, the value of the transfer characteristic T I´ / I(f) can be improved, and the temperature rise of the battery 30 can be further accelerated.

[0075] According to the motor control method of this embodiment described above, in the warm-up control mode, the switch 70 that switches the electrical connection and disconnection between the inverter 40 and the battery 30 is operated based on a temperature parameter (rate of temperature rise) that indicates the temperature of the battery 30, and the ripple current (i.e., ripple current I') generated in the battery 30 per current (i.e., per ripple current I) flowing through the electrical wiring of the inverter 40 is increased.

[0076] As a result, the transfer characteristic improvement process is executed as appropriate depending on the temperature rise state of the battery 30 during the warm-up control mode, so that the temperature rise effect of the battery 30 can be further improved.

[0077] In particular, the smoothing capacitor 42 of the inverter 40 of this embodiment is composed of a plurality of (two in this embodiment) capacitor elements 42a, 42b connected in parallel to the battery 30. In the warm-up control mode, if the temperature rise rate of the battery 30 is less than a predetermined threshold rate, the switch 70 is operated to electrically disconnect one of the capacitor elements 42a, 42b (capacitor element 42a in this embodiment) from the battery 30.

[0078] This makes it possible to appropriately detect a situation in which the intended effect of increasing the temperature of the battery 30 is not being achieved during warm-up, and to execute processing to improve the effect of increasing the temperature.

[0079] [Eighth embodiment] In this embodiment, a second aspect of the transfer characteristic improvement process will be described.

[0080] FIG. 6 is a diagram showing the main part of the circuit configuration between the battery 30 and the inverter 40 in this embodiment.

[0081] As shown in the figure, battery 30 includes a plurality of (two in the figure) unit power storage units 30a, 30b connected in parallel to inverter 40. Furthermore, unit power storage units 30a, 30b are provided with switches 70a, 70b, respectively, for switching electrical connection between inverter 40.

[0082] In the warm-up control mode, motor control device 20 turns on or off each of switches 70a, 70b individually in accordance with the magnitude of the temperature variation between unit power storage units 30a, 30b.

[0083] More specifically, when the temperature variation is equal to or greater than a certain value, the unit power storage unit 30a, 30b that has a relatively higher temperature is identified. Then, for example, when the unit power storage unit 30a has a relatively high temperature, the switch 70a is turned off and the switch 70b is turned on. As a result, the unit power storage unit 30a that has a relatively high temperature is electrically disconnected from the inverter 40, and only the unit power storage unit 30b that has a relatively low temperature is electrically connected to the inverter 40. Note that the on / off control of the switches 70a, 70b is performed using the same logic even when the unit power storage unit 30b has a relatively high temperature.

[0084] As a result, in a scene where there is a large temperature variation between unit power storage units 30a and 30b, the transfer characteristic T I´ / I The gain (f) (ripple current I' per ripple current I) can be concentrated on unit power storage unit 30b at a relatively low temperature, so that the temperature rise of unit power storage unit 30b can be prioritized.

[0085] As described above, in this embodiment, battery 30 includes a plurality of unit power storage units 30 a, 30 b. In the warm-up control mode, when the temperature variation between unit power storage units 30 a, 30 b is equal to or greater than a certain value, unit power storage unit 30 a having a relatively higher temperature among unit power storage units 30 a, 30 b is electrically disconnected from inverter 40.

[0086] This allows the temperature of unit power storage unit 30b, which has a relatively low temperature, to be raised preferentially even if there is a large temperature difference between unit power storage units 30a, 30b during warm-up. As a result, the temperatures of the plurality of unit power storage units 30a, 30b can be raised evenly, and the time required for raising the temperature of the entire battery 30 to a desired temperature (warm-up time) can be shortened.

[0087] The circuit configuration shown in this embodiment is just an example, and any circuit configuration can be adopted as long as it is possible to turn on / off the electrical connection between the multiple unit power storage units and the inverter 40 in accordance with temperature variations.

[0088] [Ninth embodiment] In this embodiment, a third aspect of the transfer characteristic improvement process will be described.

[0089] In particular, in the present embodiment, similarly to the ninth embodiment, the battery 30 includes a plurality of (two in the figure) unit power storage units 30a, 30b. The electrical connection state of each of the unit power storage units 30a, 30b to the inverter 40 is individually switched according to the temperature of the battery 30.

[0090] FIG. 7 is a diagram showing the main part of the circuit configuration between the battery 30 and the inverter 40 in this embodiment.

[0091] As shown in the figure, with the circuit configuration of this embodiment, the electrical connection state (parallel, series, or non-connection) of each unit power storage unit 30a, 30b to the inverter 40 can be switched by individually operating each switch 70c, 70d, 70e depending on the temperature of the battery 30.

[0092] Specifically, in the basic control mode, motor control device 20 sets switch 70c to ON, switch 70d to OFF, and switch 70e to OFF. On the other hand, in the warm-up control mode, motor control device 20 sets switch 70c to OFF, switch 70d to ON, and switch 70e to ON.

[0093] As a result, when not warmed up (when the motor is normally driven), unit power storage units 30a, 30b are connected in series to inverter 40, ensuring high battery output. On the other hand, when warmed up, unit power storage units 30a, 30b are connected in series to inverter 40. This reduces the combined internal resistance of battery 30, and transfer characteristic T I´ / I (f) is improved, and the temperature rise of the battery 30 is further accelerated.

[0094] As described above, in this embodiment, battery 30 includes a plurality of unit power storage units 30 a, 30 b. In the basic control mode, each of unit power storage units 30 a, 30 b is directly connected to inverter 40. On the other hand, in the warm-up control mode, each of unit power storage units 30 a, 30 b is connected in parallel to inverter 40.

[0095] This ensures high battery output in the basic control mode, while maintaining the transfer characteristic T I´ / I A control logic that improves (f) and further enhances the temperature rise effect of the battery 30 is realized.

[0096] The circuit configuration shown in this embodiment is just an example, and any circuit configuration can be adopted as long as it is possible to switch the connection between the multiple unit power storage units and the inverter 40 between direct connection and parallel connection in the basic control mode and the warm-up control mode.

[0097] [Tenth embodiment] In this embodiment, the motor control device 20 executes modulation factor adjustment control in the warm-up control mode to adjust the modulation factor M in order to promote the temperature rise of the battery 30.

[0098] Specifically, in the modulation factor adjustment control of this embodiment, the modulation factor M is determined so that the direction of the resultant magnetomotive force generated in the motor 10 coincides with the rotor magnetic pole position.

[0099] Fig. 8(A) is a diagram showing the modulation factor M adjusted by modulation factor adjustment control, the phase current of the motor 10 according to the modulation factor M, and the time evolution of the average value of each phase current (particularly the average value per carrier period). Fig. 8(B) is a phasor diagram showing the relationship between the phase current vector, the direction of the resultant magnetomotive force, and the rotor magnetic pole position when modulation factor adjustment control is executed.

[0100] As shown in the figure, in the modulation factor adjustment control, the modulation factor M is adjusted so that the direction of the resultant vector of each phase current vector (i.e., the direction of the resultant magnetomotive force created by each phase current vector) on a phasor display based on a three-phase AC coordinate system coincides with the rotor magnetic pole position (i.e., the d-axis direction) detected in advance by a predetermined sensor or the like.

[0101] According to the motor control method of the present embodiment described above, in the warm-up control mode, the modulation factor M based on the phase voltage command value is determined so that the direction of the resultant magnetomotive force generated in the motor 10 coincides with the rotor magnetic pole position. In particular, the direction of the resultant magnetomotive force is determined by the average value per carrier period of each phase current.

[0102] As a result, as described above, during the warm-up control mode, the PWM signal S is output from the warm-up carrier C2, which is different from the basic control mode. p Therefore, it is possible to more reliably prevent the generation of a torque that would otherwise affect the drive control of the motor 10 (such as the generation of an unintended motor torque).

[0103] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. Furthermore, the above embodiments can be combined in any manner possible. [Explanation of symbols]

[0104] 10 Motor 20 Motor control device 30 Battery 40 inverter 42 Smoothing capacitor 50 Electrical Connections 60 Resonance characteristic adjustment capacitor 70 Switch 100 Motor Control System

Claims

1. A motor control method for generating a switching command signal by pulse width modulation based on a carrier signal and a phase voltage command value, and controlling power supplied from a battery to a polyphase motor by operating an inverter based on the switching command signal, comprising: when it is determined that the battery is at a low temperature, the phases of at least two of the carrier signals are set to values ​​different from each other to generate the switching command signal; Motor control methods.

2. 2. The motor control method of claim 1, When the battery temperature is equal to or higher than a predetermined threshold temperature, a basic control mode is executed in which the switching command signal is generated from a basic carrier signal in which the phases of the respective phases are set to be identical to each other; When the battery temperature is lower than the threshold temperature, a warm-up control mode is executed in which the switching command signal is generated from a warm-up carrier signal in which at least two phases are set to different values. Motor control methods.

3. 3. The motor control method according to claim 2, In the basic control mode, the carrier frequency of the basic carrier signal is set to a predetermined basic frequency; In the warm-up control mode, the carrier frequency of the warm-up carrier signal is set to a warm-up frequency different from the fundamental frequency. Motor control methods.

4. 4. The motor control method according to claim 3, The warm-up frequency is set lower than the fundamental frequency. Motor control methods.

5. 4. The motor control method according to claim 3, The warm-up frequency is set so that the effective value of the current flowing through the battery is greater than the effective value of the phase current of the polyphase motor. Motor control methods.

6. 4. The motor control method according to claim 3, the inverter includes a smoothing capacitor connected in parallel to the battery; In the warm-up control mode, The warm-up frequency is set to be substantially equal to a resonant frequency in a resonant system including a capacitance of the smoothing capacitor and a parasitic inductance generated by an electrical connection between the battery and the smoothing capacitor. Motor control methods.

7. 7. A motor control method according to claim 6, comprising: a resonance characteristic adjusting capacitor connected in parallel to the battery is provided in the electrical connection between the battery and the smoothing capacitor; Motor control methods.

8. 4. The motor control method according to claim 3, In the warm-up control mode, a frequency search process is executed to search for and set the warm-up frequency at predetermined time intervals; In the frequency search process, Varying the carrier frequency within a predetermined search range and observing the current of the battery; a frequency at which the current of the battery is highest in the search range is set as the warm-up frequency; Motor control methods.

9. 3. The motor control method according to claim 2, In the warm-up control mode, operating a switch that switches an electrical connection state between the inverter and the battery to increase a ripple current generated in the battery per current flowing through the electrical connection of the inverter compared to when the basic control mode is executed; Motor control methods.

10. 10. The motor control method of claim 9, further comprising: the smoothing capacitor of the inverter is composed of a plurality of capacitor elements, In the warm-up control mode, When the rate of temperature rise of the battery is less than a predetermined threshold rate, one of the capacitor elements is electrically disconnected from the battery. Motor control methods.

11. 10. The motor control method of claim 9, further comprising: the battery includes a plurality of unit power storage units, In the warm-up control mode, when the temperature variation among the unit power storage units is equal to or greater than a certain value, electrically disconnecting the unit power storage unit having a relatively high temperature from the inverter; Motor control methods.

12. 10. The motor control method of claim 9, further comprising: the battery includes a plurality of unit power storage units, In the basic control mode, each unit power storage unit is directly connected to the inverter, In the warm-up control mode, the unit power storage units are connected in parallel to the inverter. Motor control methods.

13. 3. The motor control method according to claim 2, In the warm-up control mode, a modulation factor based on the phase voltage command value is determined so that the direction of a resultant magnetomotive force generated in the polyphase motor coincides with a rotor magnetic pole position; the direction of the resultant magnetomotive force is determined by an average value per carrier period of each phase current of the polyphase motor. Motor control methods.

14. A motor control device that generates a switching command signal by pulse width modulation based on a carrier signal and a phase voltage command value, and controls power supplied from a battery to a polyphase motor by operating an inverter based on the switching command signal, when it is determined that the battery is at a low temperature, the phases of at least two of the carrier signals are set to values ​​different from each other to generate the switching command signal; Motor control device.

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