JP2018143054A - vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress variation in output torque of a motor.SOLUTION: When a vehicle controls an inverter in a rectangular-wave control mode, it uses a rectangular-wave voltage obtained by feedback processing. The feedback processing uses an integration gain in such a manner that a difference between first estimated torque and target torque may become 0. The first estimated torque is calculated based on a current in each phase of a motor as well as a rotational angle of the motor detected by a rotational angle detection sensor. When the inverter is controlled in the rectangular-wave control mode, the integration gain is decreased at a predetermined time, compared with times other than the predetermined time. Here, the predetermined time is described as a time when: the frequency of variation in rotational speed of the motor is within a torsional resonance frequency band of an axle; and a difference between the first estimated torque and second estimated torque, which is calculated based on the current and a voltage in each phase of the motor as well as the rotational speed of the motor, is equal to or greater than a predetermined value.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a vehicle, and more particularly to a vehicle including a motor, an inverter, a rotation angle detection sensor, and a control device.

  2. Description of the Related Art Conventionally, a motor drive device has been proposed that includes an inverter that drives a motor and a rotation angle detection sensor that detects the rotation angle of the motor (for example, see Patent Document 1). In this apparatus, the inverter is controlled in a plurality of control modes including a rectangular wave control mode so that the motor is driven with the target torque. When the inverter is controlled in the rectangular wave control mode, the d-axis current and the q-axis current are calculated using each phase current of the motor and the rotation angle of the motor detected by the rotation angle detection sensor, and the calculated d The output torque of the motor is estimated using the shaft current, the q-axis current, and the torque calculation map. Then, the inverter is controlled by adjusting the voltage phase of the rectangular wave voltage so that the difference between the estimated value of the output torque of the motor and the torque command of the motor becomes 0.

JP 2007-159368 A

  In a vehicle equipped with the above-described motor drive device and connected to a drive shaft in which the rotation shaft of the motor is connected to the axle, when controlling the inverter in the rectangular wave control mode, when the rotation speed of the motor changes due to disturbance, Due to the detection delay of the rotation angle sensor, the phase of the estimated value of the output torque of the motor and the phase of the actual torque actually output from the motor may be greatly shifted. If the voltage phase of the rectangular wave voltage is adjusted so that the difference between the estimated value and the torque command is 0 while the phase between the estimated value and the actual torque is greatly deviated, the control response becomes oscillating, and The output torque has a cycle fluctuation shorter than the above-described change. Since the vibration of the vehicle increases when the frequency of such fluctuations falls within the torsional resonance frequency band of the axle, it is desirable to suppress such fluctuations.

  The main purpose of the vehicle of the present invention is to suppress fluctuations in the output torque of the motor when the inverter is controlled in the rectangular wave control mode.

  The vehicle of the present invention employs the following means in order to achieve the main object described above.

The vehicle of the present invention
A motor having a rotating shaft connected to a driving shaft connected to an axle;
An inverter for driving the motor;
A rotation angle detection sensor for detecting a rotation angle of the motor;
A control device for controlling the inverter in a plurality of control modes including a rectangular wave control mode so that the motor is driven with a target torque;
A vehicle comprising:
When the control device controls the inverter in the rectangular wave control mode, a first estimation calculated using the current of each phase of the motor and the rotation angle of the motor detected by the rotation angle detection sensor. Controlling the inverter using a rectangular wave voltage obtained by feedback processing using an integral gain so that the difference between the torque and the target torque becomes a value of 0,
Further, in the case where the control device controls the inverter in the rectangular wave control mode, the frequency of fluctuation in the rotation speed of the motor is within a torsional resonance frequency band of the axle, and the first estimated torque and The difference between the current of each phase of the motor and the voltage of each phase and the second estimated torque calculated using the rotation speed of the motor is greater than a predetermined value when compared to when it is not the predetermined time. To reduce the integral gain,
This is the gist.

  In the vehicle of the present invention, when the inverter is controlled in the rectangular wave control mode, the first estimated torque and the target calculated using the current of each phase of the motor and the rotation angle of the motor detected by the rotation angle detection sensor. The inverter is controlled using a rectangular wave voltage obtained by feedback processing using an integral gain so that the difference from torque becomes 0. When the inverter is controlled in the rectangular wave control mode, the frequency of fluctuation of the motor speed is within the torsional resonance frequency band of the axle, and the first estimated torque, the current of each phase of the motor, and the current of each phase When the difference between the voltage and the second estimated torque calculated using the number of rotations of the motor is greater than or equal to a predetermined value, the integral gain is made smaller than when it is not the predetermined time. When the frequency of fluctuations in the rotational speed of the motor is within the torsional resonance frequency band of the axle, a relatively large vibration occurs due to the resonance. Further, since the first estimated torque is calculated using the current of each phase of the motor and the rotation angle of the motor detected by the rotation angle detection sensor, it is greatly affected by the detection delay of the rotation angle detection sensor. Since the second estimated torque is calculated using the current of each phase of the motor, the voltage of each phase, and the rotation speed of the motor, the second estimated torque is less affected by the detection delay of the rotation angle detection sensor. Therefore, when a delay occurs in the detection value of the rotation angle detection sensor, the first estimated torque deviates from the actual torque actually output from the motor, but the second estimated torque becomes a value close to the actual torque. Therefore, when the frequency of fluctuation of the rotational speed of the motor is in the torsional resonance frequency band of the axle and the difference between the first estimated torque and the second estimated torque is larger than a predetermined value, it is compared with when it is not the predetermined time. By reducing the integral gain, the control response can be suppressed from becoming oscillating. Thereby, the fluctuation | variation of the rotation speed and output torque of a motor can be suppressed.

  In the vehicle of the present invention, when the phase difference between the phase of the first estimated torque and the phase of the second estimated torque is within a predetermined range including 180 °, the first estimated torque and the second estimated torque May be determined to be greater than or equal to the predetermined value. In this case, the difference between the time when the difference between the first estimated torque and the average value of the first estimated torque is 0 and the difference between the second estimated torque and the average value of the second estimated torque is 0. The phase difference may be calculated using a difference between

  Furthermore, in the vehicle of the present invention, the plurality of control modes may include the rectangular wave control mode and a PWM control mode. In this case, in the PWM control mode, the inverter may be controlled using a d-axis current and a q-axis current calculated using the current of each phase of the motor and the rotation angle.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 provided with the motor drive device as one Example of this invention. FIG. 6 is an explanatory diagram for explaining an example of a relationship between a rotational speed Nm of a motor 32, a torque command Tm *, and a control mode Md of an inverter 34. It is a block diagram for demonstrating control of the inverter 34 in a rectangular wave control mode. 4 is a flowchart showing an example of an integral gain setting process routine executed by an electronic control unit 50. It is explanatory drawing which shows the relationship between the electric currents Id and Iq of d axis | shaft and q axis | shaft, and the torque output from the motor 32. FIG. It is explanatory drawing which shows an example of the time change of estimated output torque Trq1, Trq2. When the phase difference θrq is determined to be equal to or larger than the predetermined value θref in the process of step S160, the voltage phase command θp * of the embodiment when the integral gain Ki is set to the value K2 and the processes of steps S130, S150, and S160. Regardless, the voltage phase command θp1 of the first comparative example in which the integral gain Ki is the value K1, the voltage phase command θp2 of the second comparative example that performs rectangular control feedback calculation using the actual torque Tr that is actually output as the estimated torque, It is explanatory drawing which shows an example of the time change of.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 as an embodiment of the present invention. The electric vehicle 20 according to the embodiment includes a motor 32, an inverter 34, a battery 36, a boost converter 40, and an electronic control unit 50, as illustrated.

  The motor 32 is configured as a synchronous generator motor, and includes a rotor in which a permanent magnet is embedded and a stator around which a three-phase coil is wound. The rotor of the motor 32 is connected to a drive shaft 26 connected to the drive wheels 22a and 22b via an axle 23 and a differential gear 24.

  Inverter 34 is connected to motor 32 and connected to boost converter 40 via high-voltage power line 42. The inverter 34 includes six transistors T11 to T16 and six diodes D11 to D16. Two transistors T11 to T16 are arranged in pairs so as to be on the source side and the sink side with respect to the positive electrode bus and the negative electrode bus of the high voltage power line 42, respectively. The six diodes D11 to D16 are respectively connected in parallel to the transistors T11 to T16 in the reverse direction. Each of the three-phase coils (U-phase, V-phase, W-phase) of the motor 32 is connected to each connection point between the transistors T11 to T16 as a pair. Therefore, when a voltage is applied to the inverter 34, the electronic control unit 50 adjusts the ratio of the on-time of the paired transistors T11 to T16, so that a rotating magnetic field is formed in the three-phase coil, and the motor 32 is rotationally driven. A smoothing capacitor 46 is attached to the positive and negative buses of the high voltage system power line 42.

  The battery 36 is configured as, for example, a lithium ion secondary battery or a nickel hydride secondary battery, and is connected to the boost converter 40 via the low voltage system power line 44. A smoothing capacitor 48 is attached to the positive and negative buses of the low voltage system power line 44.

  Boost converter 40 is connected to high voltage power line 42 to which inverter 34 is connected and low voltage power line 44 to which battery 36 is connected. Boost converter 40 includes two transistors T31 and T32, two diodes D31 and D32, and a reactor L. The transistor T31 is connected to the positive bus of the high voltage system power line 42. The transistor T32 is connected to the transistor T31 and the negative buses of the high voltage system power line 42 and the low voltage system power line 44. The two diodes D31 and D32 are respectively connected in parallel to the transistors T31 and T32 in the reverse direction. The reactor L is connected to a connection point between the transistors T31 and T32 and a positive bus of the low voltage system power line 44. The step-up converter 40 adjusts the on-time ratio of the transistors T31 and T32 by the electronic control unit 50 to boost the power of the low voltage system power line 44 and supply it to the high voltage system power line 42. The power of the high voltage system power line 42 is stepped down and supplied to the low voltage system power line 44.

  The electronic control unit 50 is configured as a microprocessor centered on the CPU 52, and includes a ROM 54 for storing a processing program, a RAM 56 for temporarily storing data, and an input / output port in addition to the CPU 52.

  Signals from various sensors are input to the electronic control unit 50 via input ports. As a signal input to the electronic control unit 50, for example, a rotation angle detection sensor that detects the rotation angle (rotation position) of the rotor of the motor 32 (for example, a resolver and an R that converts a signal from the resolver into a digital value). The rotation angle θm of the rotor of the motor 32 from a known rotation angle detection sensor 32a provided with a / D converter) and the current 32 flowing from the current sensors 32u and 32v for detecting the current flowing in each phase of the motor 32 to the motor 32. Examples thereof include phase currents Iu, Iv, and phase voltages Vu, Vv, Vw from a voltage sensor 32b that detects a voltage of each phase of the motor 32. Moreover, the voltage Vb from the voltage sensor 36a attached between the terminals of the battery 36 and the current Ib from the current sensor 36b attached to the output terminal of the battery 36 can also be mentioned. Furthermore, the voltage VH of the capacitor 46 (high voltage system power line 42) from the voltage sensor 46a attached between the terminals of the capacitor 46, and the capacitor 48 (low voltage from the voltage sensor 48a attached between the terminals of the capacitor 48). The voltage VL of the system power line 44) can also be mentioned. In addition, the ignition signal from the ignition switch 60 and the shift position SP from the shift position sensor 62 that detects the operation position of the shift lever 61 can also be cited. Further, the accelerator opening Acc from the accelerator pedal position sensor 64 that detects the depression amount of the accelerator pedal 63, the brake pedal position BP from the brake pedal position sensor 66 that detects the depression amount of the brake pedal 65, and the vehicle speed sensor 68 The vehicle speed V can also be mentioned.

  Various control signals are output from the electronic control unit 50 through an output port. Examples of the signal output from the electronic control unit 50 include a switching control signal to the transistors T11 to T16 of the inverter 34 and a switching control signal to the transistors T31 and T32 of the boost converter 40. The electronic control unit 50 calculates the electrical angle θe and the rotational speed Nm of the motor 32 based on the rotational angle θm of the rotor of the motor 32 from the rotational angle detection sensor 32a. Further, the electronic control unit 50 calculates the storage ratio SOC of the battery 36 based on the integrated value of the current Ib of the battery 36 from the current sensor 36b. Here, the storage ratio SOC is the ratio of the capacity of power that can be discharged from the battery 36 to the total capacity of the battery 36.

  In the electric vehicle 20 of the embodiment thus configured, the electronic control unit 50 performs the following traveling control. In the travel control, the required torque Td * required for the drive shaft 26 is set based on the accelerator opening Acc and the vehicle speed V, the set required torque Td * is set as the torque command Tm * of the motor 32, and the motor 32 Is controlled by the torque command Tm * to perform switching control of the transistors T11 to T16 of the inverter 34. Further, the target voltage VH * of the high voltage system power line 42 is set so that the motor 32 can be driven with the torque command Tm *, and the boost converter 40 is set so that the voltage VH of the high voltage system power line 42 becomes the target voltage VH *. The transistors T31 and T32 are controlled to be switched.

  Here, the control of the inverter 34 will be described. In the embodiment, for the inverter 34, a sine wave PWM (pulse width modulation) control mode, an overmodulation PWM control mode, a rectangular wave control mode, based on the target operating point (torque command Tm * and rotation speed Nm) of the motor 32. Any one of these is controlled as the control mode Md. Here, the sine wave PWM control mode is a control mode in which the inverter 34 is controlled so that a pseudo three-phase AC voltage is applied (supplied) to the motor 32. The overmodulation PWM control mode has an overmodulation voltage. The rectangular wave control mode is a control mode in which the inverter 34 is controlled so that a rectangular wave voltage is applied to the motor 32. FIG. 2 is an explanatory diagram for explaining an example of the relationship between the rotational speed Nm of the motor 32, the torque command Tm *, and the control mode Md of the inverter 34. As shown in the figure, the control mode Md of the inverter 34 includes a sine wave PWM control mode, an overmodulation PWM control mode, and a rectangular wave control mode from the side where the rotational speed Nm of the motor 32 and the torque command Tm * are small to the large side. It is determined to be.

  In the sine wave PWM control mode and the overmodulation PWM control mode, the electronic control unit 50 first determines that the sum of currents flowing in the respective phases (U phase, V phase, W phase) of the motor 32 is 0, and is a current sensor. Using the phase currents Iu and Iv of the motor 32 detected by 32u and 32v and the electrical angle θe calculated based on the rotation angle θm of the rotor of the motor 32 detected by the rotation angle detection sensor 32a, U-phase and V-phase phase currents Iu and Iv are coordinate-converted into d-axis and q-axis currents Id and Iq (three-phase to two-phase conversion). Subsequently, current commands Id * and Iq * for the d and q axes in the dq coordinate system are set from the torque command Tm * and a predetermined map. Next, the d-axis and q-axis voltage commands Vd * and Dq are used as feedback terms based on the differences ΔId and ΔIq between the d-axis and q-axis current commands Id * and Iq * and the d-axis and q-axis currents Id and Iq, respectively. Vq * is calculated. Then, using the electrical angle θe of the motor 32, the d-axis and q-axis voltage commands Vd * and Vq * are coordinate-converted into the voltage commands Vu *, Vv * and Vw * for each phase (2-phase to 3-phase conversion). The PWM signals of the transistors T11 to T16 are generated by comparing the voltage commands Vu *, Vv *, Vw and the carrier voltage, and the switching control of the transistors T11 to T16 is performed using this PWM signal.

  Next, the operation of the electric vehicle 20 of the embodiment configured as described above, particularly the operation when controlling the inverter 34 in the rectangular wave control mode will be described. FIG. 3 is a block diagram for explaining the control of the inverter 34 in the rectangular wave control mode in the electric vehicle 20.

  In the rectangular wave control mode, as shown in the figure, the electronic control unit 50 first converts the U-phase and V-phase currents Iu and Iv into the d-axis by the same processing as in the sine wave PWM control mode and overmodulation PWM control mode. , And q-axis currents Id and Iq are converted into coordinates (three-phase to two-phase conversion). Subsequently, the estimated output torque Trq1 estimated to be output from the motor 32 is set based on the d-axis and q-axis currents Id and Iq (estimated torque setting). Then, an integral gain Ki for rectangular feedback control is set (FB gain setting). The setting of the integral gain Ki will be described later. Then, using the set integral gain Ki and a predetermined proportional gain Kp, the voltage phase command θp * is expressed by the following equation (1) so that the difference between the estimated output torque Trq1 and the torque command Tm * is canceled. Calculate (rectangular control feedback calculation). When the voltage phase command θp * is thus calculated, rectangular wave signals Vu, Vv, Vw are generated so that a rectangular wave voltage based on the voltage phase command θp * is applied to the motor 32 (switching pattern output). Then, by switching the generated rectangular wave signals Vu, Vv, Vw to the inverter 34, switching control of the transistors T11 to T16 of the inverter 34 is performed. The electronic control unit 50 executes such a series of processes every predetermined time Tc (for example, every several msec). In this way, the currents Id and Iq of the d-axis and q-axis are calculated using the same state quantities (phase currents Iu and Iv and the rotation angle θm) as in the sine wave PWM control mode and the overmodulation PWM control mode. , Iq, the voltage phase command θp * is calculated so that the difference between the estimated output torque Trq1 and the torque command Tm * is canceled, and a rectangular wave voltage based on the calculated voltage phase command θp * is applied to the motor 32. Further, by controlling the inverter 34, the output torque from the motor 32 is suppressed from changing suddenly when the control mode is switched between the sine wave PWM control mode, the overmodulation PWM control mode, and the rectangular wave control.

  θp * = Kp ・ (Tm * -Trq1) + ∫Ki ・ (Tm * -Trq1) dt (1)

  Next, the setting of the integral gain Ki described above will be described. FIG. 4 is a flowchart showing an example of an integral gain setting process routine executed by the electronic control unit 50.

  When this routine is executed, the electronic control unit 50 determines the phase currents Iu and Iv of the U phase and V phase, the phase voltages Vu, Vv and Vw of the U phase, V phase and W phase, and the rotation speed Nm of the motor 22. A process of inputting the rotation angle θm is executed (step S100). As the phase currents Iu and Iv, those detected by the current sensors 22u and 22v are input. The phase voltages Vu, Vv, and Vw are those detected by the voltage sensor 32b. The rotation speed Nm is input based on the rotation angle θm of the rotor of the motor 22. The rotation angle θm is input as detected by the rotation angle detection sensor 32a.

  Subsequently, the estimated output torque Trq1 estimated to be output from the motor 22 is set based on the d-axis and q-axis currents Id and Iq (step S110). This process is a process corresponding to the estimated torque setting described above. The estimated output torque Trq1 is set by determining the relationship between the currents Id and Iq of the d-axis and q-axis and the torque output from the motor 22 by experiment or analysis and storing them as a map. The torque corresponding to when the currents Id and Iq are given is set to the estimated output torque Trq1. FIG. 5 is an explanatory diagram showing the relationship between the d-axis and q-axis currents Id and Iq and the torque output from the motor 22.

  Subsequently, the estimated output torque Trq2 is calculated using the following equation (2) (step S120). As shown in the equation (2), the estimated output torque Trq2 is assumed that the sum of the currents flowing through the phases (U phase, V phase, W phase) of the motor 22 is 0, and the phase currents Iu, Iv, Iw (= 0−Iu−Iv), voltages Vu, Vv, Vw, and rotation speed Nm. The rotation speed Nm is calculated using the rotation angle θm detected by the rotation angle detection sensor 32a. In general, when an error due to a detection delay of the rotation angle detection sensor 32a occurs, the difference between the rotation speed Nm and the actual rotation speed of the motor 22 is not so large. Therefore, the estimated output torque Trq2 is close to the torque actually output from the motor 22.

  Trq2 = (Iu ・ Vu + Iv ・ Vv + Iw ・ Vw) / Nm (2)

  Subsequently, it is determined whether or not the fluctuation amount ΔNm of the rotational speed Nm exceeds the predetermined fluctuation amount dNmref (step S130). The fluctuation amount ΔNm is calculated by subtracting the rotation speed Nm input in the process of step S100 when this routine was executed last time from the rotation speed Nm of the motor 32 input in the process of step S100. The predetermined fluctuation amount dNmref is a threshold value for determining whether or not the rotational speed Nm of the motor 32 is fluctuated due to disturbance, and is set to 50 rpm, 100 rpm, 150 rpm, or the like, for example.

  If it is determined in step S130 that the variation ΔNm is equal to or less than the predetermined variation dNmref, it is determined that the rotational speed Nm of the motor 32 has not changed, and the value K1 is set to the integral gain Ki (step S130). S140), this routine is finished. The value K1 is a predetermined value as an integral gain for quickly canceling the difference between the torque command Tm * and the estimated output torque Trq1. When the integral gain Ki is set in this way, the voltage phase is calculated using equation (1) so that the difference between the torque command Tm * and the estimated output torque Trq1 is canceled using the set integral gain Ki and the proportional gain Kp described above. The command θp * is calculated, and rectangular wave signals Vu, Vv, Vw are generated so that a rectangular wave voltage based on the voltage phase command θp * is applied to the motor 32. Then, by switching the generated rectangular wave signals Vu, Vv, Vw to the inverter 34, switching control of the transistors T11 to T16 of the inverter 34 is performed. Thereby, the torque output from the motor 32 can be quickly brought close to the torque command Tm *.

  When it is determined in step S130 that the variation ΔNm is less than the predetermined variation dNmref, it is determined whether or not the frequency fnm of variation in the rotational speed Nm is near the torsional resonance frequency fr (step S150). Here, the torsional resonance frequency fr is a frequency at which resonance occurs in the drive system (the motor 32, the differential gear 24, and the drive wheels 22a and 22b) connected to the axle 23 due to the torsion of the axle 23. In the process of step S150, when the frequency fnm is a frequency within a predetermined frequency band (resonance frequency band) centered on the resonance frequency fr, it is determined that the frequency fnm is near the resonance frequency fr.

  When the frequency fnm of the fluctuation of the rotational speed Nm is not near the torsional resonance frequency fr, it is determined that no vibration has occurred in the vehicle, the value K1 is set to the integral gain Ki (step S140), and this routine is terminated. . When such an integral gain Ki is set, the voltage phase command θp * is calculated using the set integral gain Ki and the above-described proportional gain Kp so that the difference between the torque command Tm * and the estimated output torque Trq1 is canceled, Rectangular wave signals Vu, Vv, and Vw are generated so that a rectangular wave voltage based on the voltage phase command θp * is applied to the motor 32. Then, by switching the generated rectangular wave signals Vu, Vv, Vw to the inverter 34, switching control of the transistors T11 to T16 of the inverter 34 is performed. Thereby, the torque output from the motor 32 can be quickly brought close to the torque command Tm *.

  When the frequency fnm of the fluctuation in the rotational speed Nm is near the torsional resonance frequency fr, it is determined that the vehicle is vibrating or possibly vibrating, and then the estimated output torque Trq1 and the estimated output torque Trq2 It is determined whether or not the phase difference θrq is equal to or greater than a predetermined value θref (step S160). The predetermined value θref is a value obtained in advance through experiments and analysis as a phase difference that increases the difference between the estimated output torque Trq1 and the estimated output torque Trq2, and is set to 180 ° in the embodiment. FIG. 6 shows an example of temporal changes in the estimated output torques Trq1 and Trq2. In the figure, the solid line shows an example of the time change of the estimated output torque Trq2. A broken line indicates an example of a time change of the estimated output torque Trq1. As shown in the figure, the estimated output torques Trq1 and Trq2 are sinusoidal, and the phase of the estimated output torque Trq1 becomes slower than the phase of the estimated output torque Trq2 due to the detection delay of the rotation angle detection sensor 32a. The rotation angle detection sensor 32a desirably has good responsiveness. However, if the responsiveness is too good, noise resistance is lowered, so that the responsiveness is slightly lowered. Therefore, when the rotation speed Nm of the motor 32 changes due to disturbance, a detection delay of the rotation angle θm of the motor 32 by the rotation angle detection sensor 32a occurs. Since such a detection delay occurs, as shown in the figure, the phase of the estimated output torque Trq1 is delayed with respect to the phase of the estimated output torque Trq2.

  More specifically, the determination in step S160 is performed as follows. First, torque average values Trq1_av and Trq2_av, which are average values of the estimated output torques Trq1 and Trq2, are calculated using the following equations (3) and (4). In formulas (3) and (4), “Trq1_N” and “Trq2_N” are set or calculated in the processing of steps S110 and S120 when this routine is executed N times (N is a real number greater than or equal to 1). Estimated output torque Trq1, Trq2. The value Nth is calculated using the following equation (5). In Expression (5), “ωe” is a resonance frequency (torsion resonance frequency fr) of torsional vibration of the drive system including the motor 32. Examples of the drive system include a drive system (motor, drive wheel, differential gear, etc.) connected to the drive shaft when the rotating shaft of the motor 32 is connected to the drive shaft of the vehicle. “N” is reset to 0 when the number of repetitions of this routine reaches the value Nth.

  Nth = (1 / ωe) / Tc (5)

  Then, the torque average value Trq1_av is subtracted from the estimated output torque Trq1, and the variation ΔTrq1 of the estimated output torque Trq1 from the torque average value Trq1_av is calculated. The torque average value Trq2_av is subtracted from the estimated output torque Trq2 to calculate the fluctuation amount ΔTrq2 of the estimated output torque Trq2 from the torque average value Trq2_av. Then, by determining whether or not the difference Td between the time when the fluctuation amount ΔTrq1 takes the value 0 and the time when the fluctuation amount ΔTrq2 takes the value 0 is one half or more of the period Tt of the estimated output torque Trq2. When the difference Td is equal to or greater than the period Tt, it is determined that the phase difference θrq is equal to or greater than a predetermined value θref.

  When it is determined in step S160 that the phase difference θrq is less than the predetermined value θref, it is determined that the estimated output torque Trq1 is not delayed with respect to the estimated output torque Trq2, and the value K1 is set to the integral gain Ki. (Step S140), and this routine is finished. When such an integral gain Ki is set, the voltage phase command θp * is calculated using the set integral gain Ki and proportional gain Kp so that the difference between the torque command Tm * and the estimated output torque Trq1 is canceled out. Rectangular wave signals Vu, Vv, and Vw are generated so that a rectangular wave voltage based on the command θp * is applied to the motor 32. Then, by switching the generated rectangular wave signals Vu, Vv, Vw to the inverter 34, switching control of the transistors T11 to T16 of the inverter 34 is performed. Thereby, the torque output from the motor 32 can be quickly brought close to the torque command Tm *.

  When it is determined in step S160 that the phase difference θrq is greater than or equal to the predetermined value θref, the integral gain Ki is set to a value K2 smaller than the value K1 (step S170), and this routine is terminated. When the integral gain Ki is set in this way, the voltage phase command θp * is calculated so that the difference between the torque command Tm * and the estimated output torque Trq1 is canceled using the set integral gain Ki and proportional gain Kp. Rectangular wave signals Vu, Vv, and Vw are generated so that a rectangular wave voltage based on the command θp * is applied to the motor 32. Then, by switching the generated rectangular wave signals Vu, Vv, Vw to the inverter 34, switching control of the transistors T11 to T16 of the inverter 34 is performed.

  FIG. 7 shows the voltage phase command θp * of the embodiment when the integral gain Ki is set to the value K2 when the phase difference θrq is determined to be equal to or larger than the predetermined value θref in the process of step S160, and steps S130, S150, Regardless of the processing of S160, the voltage phase command θp1 of the first comparative example in which the integral gain Ki is the value K1, and the voltage phase of the second comparative example that performs rectangular control feedback calculation using the actual torque Tr that is actually output as the estimated torque. It is explanatory drawing which shows an example of the time change of instruction | command (theta) p2. In the figure, the solid line is the voltage phase command θp * of the embodiment. The broken line is the voltage phase command θp1 of the first comparative example. The one-dot chain line is the voltage phase command θp2 of the second comparative example. As shown in the figure, the voltage phase command θp * of the embodiment is smaller in delay than the voltage phase command θp2 of the second comparative example compared to the voltage phase command θp1 of the first comparative example. Thus, by calculating the voltage phase command θp * with the integral gain Ki as the value K2, the voltage phase command θp * can be brought close to the voltage phase command θp2 of the second comparative example. Thereby, the rotation speed fluctuation | variation and torque fluctuation | variation of the motor 32 by a control response becoming vibration can be suppressed. Therefore, the vibration of the vehicle can be suppressed.

  According to the electric vehicle 20 of the embodiment described above, when controlling the inverter 34 in the rectangular wave control mode, the phase currents Iu, Iv, Iw of the motor 32 and the rotation angle θm detected by the rotation angle detection sensor 32a Is used to control the inverter 34 using a rectangular wave voltage obtained by feedback processing using the integral gain Ki so that the difference between the estimated output torque Trq1 calculated using and the target torque Tm * becomes 0. When the frequency fnm of the fluctuation of the rotation speed Nm is within the resonance frequency band and the difference θrq between the phase of the estimated output torque Trq1 and the phase of the estimated output torque Trq2 is equal to or greater than the predetermined phase θref, the integral gain Ki is By setting the value K2 smaller than K1, fluctuations in the output torque of the motor 32 can be suppressed.

  In the electric vehicle 20 of the embodiment, it is determined whether or not the phase difference θrq between the estimated output torque Trq1 and the estimated output torque Trq2 is greater than or equal to a predetermined value θref in the process of step S160. Since it suffices to determine whether or not the difference from the estimated output torque Trq2 is greater than or equal to a predetermined value, it may be determined using a method different from whether or not the phase difference θrq is greater than or equal to the predetermined value θref.

  In the electric vehicle 20 of the embodiment, the boost converter 40 is provided between the battery 36 and the inverter 34, but the boost converter 40 may not be provided.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor 32 corresponds to the “motor”, the inverter 34 corresponds to the “inverter”, the rotation angle detection sensor 32 a corresponds to the “rotation angle detection sensor”, and the electronic control unit 50 becomes the “control device”. Equivalent to.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the vehicle manufacturing industry.

  20 electric vehicle, 22a, 22b drive wheel, 23 axle, 24 differential gear, 26 drive shaft, 32 motor, 32a rotation angle detection sensor, 32u, 32v, 36b current sensor, 34 inverter, 36 battery, 32b, 36a, 46a, 48a voltage sensor, 40 boost converter, 42 high voltage power line, 44 low voltage power line, 46, 48 capacitor, 50 electronic control unit, 52 CPU, 54 ROM, 56 RAM, 60 ignition switch, 61 shift lever, 62 Shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 brake pedal, 66 brake pedal position sensor, 68 vehicle speed sensor, D11 to D16, D31, D32 diode, L reaction Toll, T11-T16, T31, T32 transistors.

Claims (1)

A motor having a rotating shaft connected to a driving shaft connected to an axle;
An inverter for driving the motor;
A rotation angle detection sensor for detecting a rotation angle of the motor;
A control device for controlling the inverter in a plurality of control modes including a rectangular wave control mode so that the motor is driven with a target torque;
A vehicle comprising:
When the control device controls the inverter in the rectangular wave control mode, a first estimation calculated using the current of each phase of the motor and the rotation angle of the motor detected by the rotation angle detection sensor. Controlling the inverter using a rectangular wave voltage obtained by feedback processing using an integral gain so that the difference between the torque and the target torque becomes a value of 0,
Further, in the case where the control device controls the inverter in the rectangular wave control mode, the frequency of fluctuation in the rotation speed of the motor is within a torsional resonance frequency band of the axle, and the first estimated torque and The difference between the current of each phase of the motor and the voltage of each phase and the second estimated torque calculated using the rotation speed of the motor is greater than a predetermined value when compared to when it is not the predetermined time. To reduce the integral gain,
vehicle.

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