Vehicle control device

Abstract

To suppress torque fluctuations during switching between control based on pulsed torque commands and control based on normal torque commands, and to reduce vibrations caused by resonance generated in a drive transmission mechanism.SOLUTION: In a vehicle drive device, a torque command generation part selectively executes discontinuous command generation processing, which generates discontinuous command values as torque commands according to requested torque, and normal command generation processing, which generates command values as torque commands that continuously change according to the requested torque. When switching from the normal command generation processing to the discontinuous command generation processing, the torque command generation part further executes first vibration damping processing (#5), in which a notch filter is applied. The notch filter attenuates vibrations at target frequencies corresponding to the resonance frequency of the drive transmission mechanism, which transmits power between the rotating electric machine and wheels, in response to the torque commands.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 10-243680 discloses a control device that controls the drive of a rotating electric machine based on a pulse-shaped torque command value whose average value coincides with a specified required torque and whose peak value coincides with a torque value that can drive the rotating electric machine with high efficiency. Regardless of the required torque, the rotating electric machine can be driven in an efficient operating range, allowing the rotating electric machine to operate with high energy efficiency. Therefore, improvement in the power consumption rate (electricity cost) of hybrid vehicles and electric vehicles can be expected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-243680 Summary of the Invention [Problem to be solved by the invention]

[0004] Comparing a pulse-like discontinuous torque command with a normal continuous torque command, the normal torque command provides better responsiveness for rotating electric machine control based on the torque command. Therefore, a pulse-like discontinuous torque command is often used in situations where the required torque is relatively stable, such as when the vehicle is cruising, rather than in situations where the required torque fluctuates significantly. Therefore, control based on the pulse-like torque command and control based on the normal torque command can be switched as needed. In particular, when switching from control based on the normal torque command to control based on the pulse-like torque command, fluctuations in the output torque of the rotating electric machine are likely to occur. Furthermore, resonance with the frequency of the fluctuation component when torque fluctuations occur can also cause vibrations in the drive transmission mechanism that transmits power between the rotating electric machine and the wheels. If this vibration is transmitted to the occupants, it can lead to a deterioration in ride comfort.

[0005] In view of the above, it is desirable to suppress torque fluctuations when switching between control based on a pulsed torque command and control based on a normal torque command, thereby reducing vibrations due to resonance occurring in the drive transmission mechanism. [Means for solving the problem]

[0006] In view of the above, a vehicle drive device is a vehicle control device that controls a vehicle equipped with a rotating electric machine as a driving force source for wheels, and includes a torque command generation unit that generates a torque command, which is a command for causing the rotating electric machine to output a required torque, based on a required torque, which is the torque that is required to be transmitted to the wheels. The torque command generation unit selectively executes a discontinuous command generation process that generates a discontinuous command value as the torque command according to the required torque, and a normal command generation process that generates a command value that changes continuously according to the required torque as the torque command. When switching from the normal command generation process to the discontinuous command generation process, the vehicle drive device further executes a first vibration suppression process that applies a notch filter to the torque command to reduce vibrations of a target frequency that corresponds to a resonant frequency of a drive transmission mechanism that transmits power between the rotating electric machine and the wheels.

[0007] According to this configuration, the notch filter can effectively reduce vibrations due to resonance in the drivetrain when switching from a normal torque command, which has a continuously changing value, to a torque command with a discontinuous value. This reduces vehicle vibrations, improving passenger comfort. In particular, the notch filter reduces vibrations at target frequencies corresponding to the resonant frequencies of the drivetrain. This effectively reduces vibrations due to resonance in the drivetrain even when the rotating electric machine is driven based on a discontinuous torque command value. That is, according to this configuration, torque fluctuations are suppressed when switching between control based on a pulsed torque command and control based on a normal torque command, thereby reducing vibrations due to resonance in the drivetrain.

[0008] Further features and advantages of the vehicle control device will become apparent from the following description of exemplary, non-limiting embodiments that refer to the drawings. [Brief explanation of the drawings]

[0009] [Figure 1] Schematic block diagram showing an example of a drive control system for a rotating electric machine [Figure 2] Schematic control block diagram of a rotating electrical machine via an inverter [Figure 3] FIG. 1 is a diagram illustrating an example of a drive transmission mechanism between a rotating electric machine and wheels; [Figure 4] A diagram showing the operating range of a rotating electrical machine as a function of rotational speed and torque. [Figure 5] FIG. 1 is a diagram showing the relationship between a normal continuous torque command and a discontinuous torque command. [Figure 6] FIG. 1 is a waveform diagram showing an example of resonant vibration that occurs in a drive transmission mechanism when switching from a normal continuous torque command to a discontinuous torque command. [Figure 7] Graph showing the relationship between notch filter gain and elapsed time [Figure 8] 1 is a waveform diagram showing a torque command having a pulse width modulation waveform and a waveform obtained when a notch filter is applied to the torque command; [Figure 9] 1 is a waveform diagram showing a comparison example of resonant vibration when a notch filter is applied to a torque command having a pulse width modulation waveform and when a notch filter is not applied to the torque command; [Figure 10] Control block diagram showing an example of rotation speed feedback vibration suppression control [Figure 11] FIG. 10 is a waveform diagram showing a comparison example between a case where a torque for rotational speed feedback vibration suppression control is added to a torque command after switching from a discontinuous torque command to a normal continuous torque command and a case where the torque is not added. [Figure 12] 1 is a waveform diagram showing a comparison example of resonant vibration when a torque of rotational speed feedback vibration suppression control is added to a normal continuous torque command and when it is not added. [Figure 13] 10 is a flowchart showing an example of vibration suppression processing; DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a vehicle control device will be described with reference to the drawings. The schematic block diagram of Fig. 1 shows an example of a drive control system for a rotating electric machine 4. The schematic control block diagram of Fig. 2 shows an example of a control form for the rotating electric machine 4 via an inverter 7. Fig. 3 shows an example of a drive transmission mechanism 5 between the rotating electric machine 4 and wheels W.

[0011] The vehicle control device 1 controls at least an AC rotating electric machine 4 that is a driving force source for wheels W. As shown in FIG. 1, the drive control system for the rotating electric machine 4 includes the vehicle control device 1 and an inverter 7. In this embodiment, the vehicle control device 1 includes a driving control function unit (for example, driving control device 2) and a rotating electric machine control function unit (for example, rotating electric machine control device 3). The driving control device 2 controls the rotating electric machine 4 to generate a required torque Tmg in response to the driver's operation of an accelerator pedal, a brake pedal, or the like (all not shown), or commands from an adaptive cruise control system, a parking assistance system, an automatic braking system, or the like (all not shown). * The rotary electric machine control device 3 generates the required torque Tmg by, for example, current feedback control, which will be described later. * The rotating electrical machine 4 is driven and controlled via the inverter 7 so as to output the above.

[0012] In this embodiment, the rotating electric machine 4 includes a stator 42 having a multi-phase (here, three-phase) stator coil 43, and a rotor 41 having a field magnet. If the rotating electric machine 4 is a permanent magnet synchronous rotating electric machine (PMSM: Permanent Magnet Synchronous Motor), the rotor 41 includes a permanent magnet. If the rotating electric machine 4 is an electrically excited synchronous rotating electric machine (EESM: Electrically Excited Synchronous Motor), the rotating electric machine 4 includes an electromagnet using a field winding (rotor coil) instead of a permanent magnet as a field source. In this embodiment, the rotating electric machine 4 will be described as a PMSM.

[0013] 2, the vehicle control device 1 includes a current feedback control unit 12 and a modulation unit 13. In this embodiment, the current feedback control unit 12 and the modulation unit 13 are provided in the rotary electric machine control device 3. The current feedback control unit 12 is configured to * Torque command T based on * Based on the rotational position of the rotor 41 (magnetic field pole position), the rotational speed of the rotor 41, and the currents flowing through the stator coils 43 of each of the three phases, current feedback control using, for example, vector control is performed to drive and control the rotating electric machine 4 via the inverter 7. In the vector control method, feedback control is performed by converting the currents flowing through the stator coils of each phase into vector components of the d-axis, which is the direction of the magnetic field in the rotor 41, and the q-axis, which is orthogonal to the d-axis (a direction leading the magnetic field direction by an electrical angle of π / 2). The coordinate system after the coordinate conversion is called a dq-axis orthogonal coordinate system. Vector control is well known, so a detailed description will be omitted. The modulator 13 modulates the voltage command generated by the current feedback controller 12 to generate a pulse signal for controlling the switching of the switching elements of the inverter 7.

[0014] The current flowing through the stator coil 43 is detected by a current sensor 61. The rotational position and rotational speed of the rotor 41 are detected by a rotation sensor 62, such as a resolver or an inductive position sensor. The rotating electric machine control device 3 (current feedback control unit 12) is configured to have various functional units for current feedback control, and each functional unit is realized by cooperation between hardware such as a microcomputer configured with an electronic circuit as its core and software (program). Note that the vehicle control device 1 is configured to have various functional units in addition to the current feedback control unit 12, modulation unit 13, and torque command generation unit 11 (described later), and each functional unit is realized by cooperation between hardware such as a microcomputer configured with an electronic circuit as its core and software (program).

[0015] The stator coil 43 is connected to the DC power supply 6 via the inverter 7. A DC link capacitor 63 (smoothing capacitor) that smoothes the voltage on the DC side of the inverter 7 is provided on the DC side of the inverter 7, i.e., between the inverter 7 and the DC power supply 6. The rotating electrical machine control device 3 controls the switching of the inverter 7, which is made up of a plurality of switching elements, and causes the inverter 7 to convert power between DC and multi-phase (three-phase in this embodiment) AC.

[0016] The inverter 7 is configured with a plurality of switching elements. The inverter 7 has a plurality of sets (three sets in this example) of arms for one AC phase, each set being a series circuit of an upper-stage switching element on the positive side of DC and a lower-stage switching element on the negative side. The switching elements are power transistors such as IGBTs (Insulated Gate Bipolar Transistors), power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), and HEMTs (High Electron Mobility Transistors).

[0017] The DC power supply 6 is configured by, for example, a rechargeable secondary battery (battery) such as a lithium ion battery, an electric double layer capacitor, etc. When the rotating electric machine 4 is the driving power source of the vehicle as in this embodiment, the DC power supply 6 is a high-voltage, large-capacity DC power supply, and its rated voltage is, for example, 200 to 800 volts.

[0018] The rotating electric machine 4 has a function as a motor that receives power from the DC power supply 6 to generate power, and a function as a generator that receives power from the wheels W to generate power. That is, the rotating electric machine 4 generates driving force by running using the power stored in the DC power supply 6, and also generates power using the driving force transmitted from the wheels W to charge the DC power supply 6.

[0019] As shown in FIG. 3 , in this embodiment, the drive transmission mechanism 5 that transmits power between the rotating electric machine 4 and the wheels W includes an input member 51, a gear mechanism 50, and a drive shaft 59. The input member 51 is connected to the rotor shaft 40 that rotates integrally with the rotor 41 of the rotating electric machine 4, and rotates integrally with the rotor shaft 40 and the rotor 41. The input member 51 is drivingly connected to a transmission (here, a reducer) configured, for example, by a spur gear counter gear mechanism, a planetary gear mechanism, or the like. The transmission (reduction gear) may have a fixed gear ratio (fixed reduction ratio), or may be a stepped transmission (reduction gear). The reducer is drivingly connected to a differential gear mechanism 55 (distribution differential gear mechanism) that distributes power to a pair of wheels W. The differential gear mechanism 55 distributes power to a pair of drive shafts 59, and power from the rotating electric machine 4 is transmitted to the pair of wheels W via the pair of drive shafts 59. The differential gear mechanism 55 may be configured by a bevel gear type or a planetary gear type. In this embodiment, an electric vehicle having only the rotating electric machine 4 as a driving force source for the wheels W is exemplified, but this does not preclude a hybrid vehicle also having an internal combustion engine mounted thereon.

[0020] In addition, when a reducer using a planetary gear mechanism is provided and the reducer is arranged coaxially with the rotor 41, the differential gear mechanism 55 can be arranged on a separate, parallel axis from the rotor 41, and the vehicle drive device 10 including the rotating electric machine 4 can have, for example, a two-shaft configuration. In addition, when a reducer using a counter gear mechanism is provided, the vehicle drive device 10 can have a three-shaft configuration with three parallel axes, or a two-shaft configuration with two parallel axes in which the differential gear mechanism 55 is arranged coaxially with the rotor 41, folding back from the reducer. In addition, the vehicle drive device 10 can have a single-shaft configuration in which one drive shaft 59 penetrates radially inside the rotor shaft 40, and the rotor 41, the reducer using a planetary gear mechanism, and the differential gear mechanism 55 using a planetary gear mechanism are arranged coaxially. Naturally, the vehicle drive device 10 may be configured with four or more rotating axes.

[0021] In this specification, the term "driving connection" refers to a state in which two rotating elements are connected to each other so as to transmit a driving force, and includes a state in which the two rotating elements are connected to rotate integrally, or a state in which the two rotating elements are connected to each other so as to transmit a driving force via one or more transmission members. Examples of such transmission members include various components that transmit rotation at the same speed or at variable speeds, such as shafts, gear mechanisms, belts, and chains. The transmission members may also include engagement devices that selectively transmit rotation and driving force, such as friction engagement devices and meshing engagement devices. In this specification, the term "integrally rotated" refers to integral rotation regardless of whether the components are separable or inseparable. In other words, multiple components that rotate integrally may be integrally formed from the same material, or may be made of separate materials and integrated by welding, spline connection, or the like.

[0022] As described above, the current feedback control unit 12 calculates the required torque Tmg, which is the torque that is required to be transmitted to the wheels W. * Based on this, current feedback control is performed to drive and control the rotating electric machine 4 via the inverter 7. Here, the "torque required to be transmitted to the wheels W" is considered to be equivalent to the "torque to be output from the rotating electric machine 4", and the "required torque" is defined as "Tmg * " Required torque Tmg * is provided from the cruise control device 2 based on information from the accelerator pedal, etc., as described above.

[0023] As shown in FIG. 2, the vehicle control device 1 of this embodiment calculates the required torque Tmg * Based on this, the rotating electric machine 4 is supplied with a required torque Tmg * The torque command T * That is, the torque command generating unit 11 generates the required torque Tmg * Based on this, the rotating electric machine 4 is requested to generate a torque Tmg * Torque command T to output *In this embodiment, the torque command generating unit 11 performs the torque command generating process to generate the required torque Tmg * The torque command T * and the discontinuous command generation process to generate the required torque Tmg * The torque command T * The process is configured to be able to selectively execute a normal command generation process that generates a command as follows:

[0024] As will be described later, in the present embodiment, in the discontinuous command generation process, the torque command T is generated as a pulse width modulation waveform that switches between an ON state and an OFF state at a switching timing defined based on a control period Pcnt that is shorter than the set carrier period Pca. * For example, it is preferable that the carrier period Pca is set to about 10 [Hz]. The control period Pcnt is approximately 1000 times the carrier period, or approximately 5 to 20 [kHz]. The carrier period Pca may be predetermined as a fixed value, or may be variably set within a predetermined range. The torque command generation unit 11 may be provided in the travel control device 2 or in the rotating electrical machine control device 3.

[0025] Torque command T of pulse width modulation waveform * When the rotating electric machine 4 is driven by the carrier frequency, the on-state and the off-state are switched within the carrier period Pca, and therefore, torque fluctuations according to the carrier frequency may occur in the output torque of the rotating electric machine 4. For this reason, the carrier period Pca is set to be equal to the torque command T * The period is set so that torque fluctuations of the rotating electric machine 4, which is drive-controlled by the torque fluctuation control circuit, are not perceived by vehicle occupants. Perception by occupants includes vibrations caused by torque fluctuations and sounds generated by torque fluctuations. For example, the sounds (audible noise) are evaluated based on frequencies observed in a path from the mount of the rotating electric machine 4 as an input to the seat rails that secure the seat in place inside the vehicle cabin, through experiments and simulations using an actual vehicle.

[0026] 4 and 5, the torque command T * As shown in FIG. 5, the torque command generation process (discontinuous command generation process = pulse width modulation command generation process) for generating the required torque Tmg * is provided to the torque command generator 11 as a continuously changing command value. The torque command generator 11 calculates the required torque Tmg at a strobe point (or a compare point) defined in the carrier period Pca. * In this embodiment, the torque command generator 11 acquires the value of the required torque Tmg at the starting point of the carrier period Pca. * The latched required torque Tmg is fetched. * The value of is the torque command T generated as a pulse width modulated waveform. * This corresponds to the average value in the carrier period Pca of the PWM average command value Tpwm0 * It is called.

[0027] The carrier period Pca is controlled by a carrier counter. The carrier counter is a counter that increments from zero at a control period Pcnt that is shorter than the carrier period Pca. When it reaches a set maximum value, it returns to zero and repeats the counting operation. In this embodiment, the value of the carrier counter is referred to as a counter value CNT. If this maximum value is fixed, the carrier period Pca becomes a fixed value. If the maximum value is variable, the carrier period Pca can be made variable. Naturally, this counter may be in a form that decrements from the maximum value to zero, or may be a timer that measures from the maximum value to zero.

[0028] Incidentally, the rotating electric machine 4 has an operating region where loss is small and it can operate with high energy efficiency. FIG. 4 shows the operating region of the rotating electric machine 4 indicated by the rotation speed and torque of the rotating electric machine 4. The first region R1 in FIG. 4 is a region where energy efficiency is higher than that of the second region R2, and the second region R2 is a region where energy efficiency is higher than that of the third region R3. For example, when the speed of the rotating electric machine 4 is "V1", the torque "Tef" is a highly efficient torque that the rotating electric machine 4 can output with high energy efficiency. In the pulse width modulation command generation process, the torque command T in the ON state is * The torque command T is set so that the on-torque value Ton, which is the value of * is generated. The carrier frequency (1 / carrier period Pca) is a frequency that is sufficiently high relative to the frequency at which the average torque that balances with the running resistance RL changes. Therefore, torque fluctuations of the high-frequency components that correspond to the carrier frequency and are included in the output torque of the rotating electric machine 4 are not transmitted to the rotating shaft of the wheel W, and only the low-frequency components (average torque) of the output torque are transmitted to the wheel W.

[0029] In this embodiment, the torque command T * In other words, the torque command generating unit 11 generates a torque (high efficiency torque Tef) that is set in accordance with the rotation speed of the rotating electrical machine 4 and falls within a high efficiency range (for example, a first region R1) in which the efficiency of the rotating electrical machine 4 is higher than a predetermined specified value, by using the torque command T * (on-torque value Ton), and zero is the torque command T * The value (off torque value Toff) is set to be the value of the torque required for the DC power supply 6 to be turned on. When the pulse width modulation waveform is in the off state, it is preferable to control all switching elements of the inverter 7 to be in the off state and shut down the inverter 7. Since no current flows from the DC power supply 6 to the stator coil 43 via the inverter 7, it is possible to improve the power efficiency (power consumption rate).

[0030] The high efficiency range may be set on a map such as that shown in FIG. 4, or may be set based on an efficiency (for example, an index obtained by dividing output power by power consumption) determined according to the vehicle speed (the rotation speed of the rotating electric machine 4).

[0031] In the pulse width modulation command generation process, the torque integral value in the carrier period Pca is first calculated as the PWM average command value Tpwm0 * To match the PWM basic command Tpwm * Specifically, the torque command generation unit 11 calculates an on-duty Don, which is the on-state period of the pulse width modulation waveform. Since the off-duty Doff, which is the off-state period of the pulse width modulation waveform, is the period obtained by subtracting the on-duty Don from the carrier period Pca, it is sufficient to calculate the on-duty Don. The torque command generation unit 11 generates a PWM basic command Tpwm using the following equation (1): * Calculate the on-duty Don of

[0032] Don(for Tpwm * )=(Tpwm0 * / Tef)·Pca···(1)

[0033] The on-duty Don calculated in this way is an ideal value, as will be described later. The vehicle control device 1 including the torque command generation unit 11 is configured with a processor such as a microcomputer as its core, and executes processing depending on a control period that depends on a clock or the like. For this reason, command values ​​transmitted between functional units, information input and acquired from the outside, and information and signals output to the outside change for each control period determined by the processor. In the pulse width modulation command generation process, the PWM torque command Tpwm having a pulse width modulation waveform is also a signal (information) that changes for each control period. The PWM torque command Tpwm of this embodiment also changes for each control period Pcnt. The torque command generation unit 11 generates a torque command (PWM torque command Tpwm) as a pulse width modulation waveform that switches between an on state and an off state at a switching timing defined based on the control period Pcnt, which is shorter than the carrier period Pca, during a set carrier period Pca. In contrast, the PWM basic command Tpwm * is the required torque Tmg * This is a virtual and ideal command that is set as a waveform that switches between an ON state and an OFF state in response to the command, regardless of the control period Pcnt.

[0034] As described above, the resolution of the PWM torque command Tpwm depends on the control period Pcnt. The on-duty Don of the PWM torque command Tpwm is the product of the control period Pcnt and the counter value CNT (for example, "CNTon") corresponding to the on-period, as shown in the following equation (2).

[0035] Don(for Tpwm)=Pcnt·CNT···(2) (Don(for Tpwm)=Pcnt·CNTon···(2))

[0036] In this embodiment, as shown in the following formula (3), the PWM basic command Tpwm *The counter value CNT (=CNTon) corresponding to the on-duty Don of the PWM torque command Tpwm is calculated by dividing the on-duty Don by the control period Pcnt. In this embodiment, the calculation is performed using an integer operator (such as Int), and the counter value CNT is calculated by rounding down.

[0037] CNT = Don(for Tpwm * ) / Pcnt···(3) (CNTon=Don(for Tpwm * ) / Pcnt···(3))

[0038] The on-duty Don of the PWM torque command Tpwm calculated by rounding down is the PWM basic command Tpwm in each carrier period Pca. * The length is less than the on-duty Don.

[0039] As described above, the torque command generator 11 calculates the required torque Tmg * The torque command T * and the discontinuous command generation process (here, pulse width modulation command generation process) that generates the required torque Tmg * The command value (e.g., the required torque Tmg) changes continuously depending on the * The torque command T * The process is configured to be able to selectively execute a normal command generation process that generates a command as follows:

[0040] Pulse-shaped discontinuous torque command (for example, PWM torque command Tpwm) and normal continuous torque command (for example, Tmg *), the normal torque command provides better responsiveness in rotating electrical machine control based on the torque command. It is possible to improve responsiveness by shortening the carrier period Pca, for example, but shortening the off-duty Doff also shortens the period in which no current flows through the stator coil 43, which tends to reduce the effect of improving the power consumption rate by using the PWM torque command Tpwm. Therefore, a pulse-like discontinuous torque command is used when the required torque Tmg is not fluctuating significantly, and the required torque Tmg * is often used in a relatively stable situation, for example, when the vehicle is cruising. Therefore, control based on a pulsed torque command and control based on a normal torque command can be switched appropriately.

[0041] However, due to differences in responsiveness in rotating electric machine control, fluctuations are likely to occur in the output torque of the rotating electric machine 4 when the attribute of the torque command is switched. In particular, fluctuations are likely to occur in the output torque of the rotating electric machine 4 when switching from control based on a normal torque command to control based on a pulsed torque command. Furthermore, resonance with the frequency of the fluctuation component when torque fluctuations occur may also cause vibrations in the drive transmission mechanism 5 (mainly the drive shaft 59) that transmits power between the rotating electric machine 4 and the wheels W. If this vibration is transmitted to the occupants, it will lead to a decrease in ride comfort.

[0042] 6 shows an example in which a transition from normal command generation processing (Normal) to pulse width modulation command generation processing (PWM) at time t1 occurs, and then a transition back to normal command generation processing (Normal) at time t3 occurs. The waveforms show, from the top to bottom, (1) the output torque of the rotating electric machine 4, (2) the resonance component of the drive shaft 59 extracted by a band-pass filter from the vibration component contained in the output torque of the rotating electric machine 4, and (3) G vibrations generated by the resonance component of the torque transmitted to the drive shaft 59. It can be seen that G vibrations with large amplitude occur in a first period B1 after control is switched from control based on the normal torque command to control based on a pulsed torque command, and in a second period B2 after control based on the pulsed torque command is switched to control based on the normal torque command.

[0043] Note that G vibration occurs throughout the entire period between time t1 and time t3, i.e., the period during which control based on the PWM torque command Tpwm is being executed. This vibration is caused by the carrier frequency of the PWM torque command Tpwm, and has a higher frequency than the vibration component due to resonance described above. Therefore, it is difficult for occupants to sense and does not pose a problem. The vehicle control device of this embodiment is configured to suppress torque fluctuations when switching between control based on a pulsed torque command and control based on a normal torque command, thereby reducing vibration due to resonance occurring in the drivetrain mechanism.

[0044] The torque command generation unit 11 that executes the torque command generation process generates the torque command T * In contrast, the resonance frequency of the drive transmission mechanism 5 that transmits power between the rotating electric machine 4 and the wheels W (the natural angular frequency ω n The first damping process is then performed to apply a notch filter that reduces vibrations at a target frequency corresponding to the target frequency. The target frequency is determined from a resonance frequency that occurs in the drive transmission mechanism 5, such as the drive shaft 59. Naturally, the target frequency may be set to have a certain bandwidth.

[0045] The first damping process, which applies a notch filter, is * The torque command T generated by the torque command generator 11 is fed forward. * = PWM torque command Tpwm) is U(s), the notch filter is N(s), and the output (i.e., the torque command T * ) is Y(s), and the feedforward control is expressed by the following equation (4).

[0046]

number

[0047] where: s : Laplace operator ω n : Natural angular frequency (parameter that indicates speed of response) ζ: damping coefficient (a parameter that indicates stability) is.

[0048] When viewed from the output Y(s), equation (4) is expressed by the following equation (5).

[0049]

number

[0050] In this embodiment, a notch filter with gain as shown in the following equations (6) and (7) is used as the notch filter N(s), where G represents the gain.

[0051]

number

[0052] In this embodiment, in the first vibration suppression process, after switching from the normal command generation process to the discontinuous command generation process, the torque command generation unit 11 changes the gain G so as to gradually reduce the notch effect of the notch filter to zero. That is, when switching from the normal command generation process to the discontinuous command generation process at time t1, as shown in FIG. 7 , the notch filter N(s) is immediately applied to the PWM torque command Tpwm at time t1, and the gain G is gradually changed from zero to 1 as time approaches t2. As is clear from equation (7), when the gain G increases to 1, the second term in the denominator of the right-hand side of equation (7) becomes zero, and the notch effect becomes zero. This process of changing the gain so as to gradually reduce the notch effect of the notch filter to zero is referred to as a "notch effect reduction process." The first vibration suppression process (notch effect reduction process) is preferably started simultaneously with switching from the normal command generation process to the discontinuous command generation process.

[0053] By reducing the notch effect over time in this way, it is possible to achieve notch effect reduction processing with a simple control configuration. However, this does not preclude reducing the notch effect in response to a decrease in vibration due to resonance, for example, based on the detection of vibration of the drive shaft 59.

[0054] FIG. 8 shows a simulated waveform of the PWM torque command Tpwm when switching from the normal command generation process to the discontinuous command generation process. The dashed line shows the PWM torque command Tpwm without the notch filter, and the solid line shows the PWM torque command Tpwm with the notch filter. As is clear from FIG. 8, applying the notch filter distorts the rectangular wave of the PWM torque command Tpwm, and the on-torque value Ton and the off-torque value Toff do not become constant values. With regard to the on-torque value Ton, the high-efficiency torque Tef cannot be used, making it difficult to achieve the effect of improving efficiency using the PWM torque command Tpwm. Furthermore, with regard to the off-torque value Toff, it is impossible to execute control (e.g., shutdown control) to set the output torque of the rotating electrical machine 4 to zero [Nm], making it difficult to achieve the effect of improving efficiency.

[0055] As is clear from the first period B1 in Fig. 6, vibrations due to resonance occurring in the drive transmission mechanism become a problem for a while after switching from normal command generation processing to discontinuous command generation processing. Therefore, by operating the notch filter only during the period when G vibrations become a problem, the effect of improving efficiency can be obtained by controlling the rotating electrical machine 4 using the PWM torque command Tpwm.

[0056] Fig. 9 shows a comparison of simulated waveforms of resonant vibration when a notch filter is applied to the PWM torque command Tpwm and when it is not applied. As in Fig. 8, the dashed line shows the PWM torque command Tpwm without the notch filter applied, and the solid line shows the PWM torque command Tpwm with the notch filter applied. As is clear from Fig. 9, by applying the notch filter, G vibration is significantly suppressed.

[0057] On the other hand, when switching from discontinuous command generation processing to normal command generation processing, the torque command T * Even if a notch filter is applied, it is difficult to obtain an effect. * does not fluctuate significantly, especially when the vehicle is cruising at a nearly constant speed. Therefore, it is difficult for a resonant frequency component with the drive transmission mechanism 5 to occur. However, immediately after the switching, G vibration occurs as shown in the second period B2 in Figure 6.

[0058] Therefore, in this embodiment, after switching from discontinuous command generation processing to normal command generation processing, the torque command generation unit 11 executes second vibration suppression processing to output torque in the opposite phase to the vibration of the drive transmission mechanism 5 to the rotary electric machine 4. The second vibration suppression processing is executed by feedback control. FIG. 10 is a control block diagram showing an example of second vibration suppression control by rotation speed feedback vibration suppression control. Based on the rotation speed ω of the rotary electric machine 4 detected by the rotation sensor 62, vibration components are extracted by passing the signal through a high-pass filter HPF, a band-pass filter BPF, and a gain amplifier, and a vibration suppression torque in the opposite phase to the vibration of the drive transmission mechanism 5 is obtained. The current feedback control unit 12 receives a torque command T * (In this case, the required torque Tmg is generated by the normal command generation process.) * The torque obtained by combining the rotational speed feedback vibration suppression control (indicated as ) and the vibration suppression torque is input as a command. The second vibration suppression process (rotation speed feedback vibration suppression control) is preferably started simultaneously with the switch from the discontinuous command generation process to the normal command generation process.

[0059] Figure 11 shows the change from a discontinuous torque command to a normal continuous torque command T * After switching to the second damping control, the torque command T *11 shows the simulated waveforms of the command input to current feedback control unit 12 when damping torque is applied by rotation speed feedback damping control to the motor and when it is not applied. As in FIG. 8, the dashed line shows the normal torque command when the second damping process is not being executed, and the solid line shows the normal torque command when the second damping process is being executed. As is clear from FIG. 11, by executing the second damping process, the normal torque command (Tmg * ) with a damping torque superimposed.

[0060] Fig. 12 shows a comparison example of simulation waveforms of resonant vibration when the second vibration damping control is executed and when it is not executed. As in Fig. 11, the dashed line shows the G vibration when the second vibration damping process is not executed, and the solid line shows the G vibration when the second vibration damping process is executed. As is clear from Fig. 12, it can be seen that the G vibration is significantly suppressed by executing the second vibration damping process.

[0061] An example of vibration damping processing including the first vibration damping processing and the second vibration damping processing will be described below with reference to a flowchart shown in FIG.

[0062] When the vibration suppression process is executed, it is first determined whether or not the PWM command is valid (step #1). As described above, the torque command generation unit 11 selectively executes the discontinuous command generation process and the normal command generation process. Therefore, in step #1, the torque command T * is the PWM torque command Tpwm.

[0063] The torque command T being generated by the torque command generating unit 11 * is the PWM torque command Tpwm, the torque command generation unit 11 activates the notch timer. This activation includes continuing to activate an already-operating notch timer. In this embodiment, the notch timer is an up-timer whose timer value increases as time passes. Therefore, the torque command generation unit 11 increments the value of the notch timer by one.

[0064] As will be described later, the torque command T * If the normal torque command is generated, the notch timer stops with the timer value remaining at zero (step #7). In step #1 of the previous loop in this flowchart, a normal torque command is generated, and in step #1 of the current loop, if a PWM torque command Tpwm is generated, the torque command T generated by the torque command generator 11 is * In this case, the process switches from normal command generation to discontinuous command generation. In this case, the stopped notch timer is started in step #2 and the timer value is incremented by one.

[0065] The torque command T generated by the torque command generating unit 11 has already * However, if the process has switched from the normal command generation process to the discontinuous command generation process, the notch timer has already been started. The torque command generation unit 11 keeps the notch timer running and increments the timer value by one.

[0066] Next, the torque command generator 11 adjusts the notch gain. Specifically, the notch gain is adjusted so that the notch effect decreases as the timer value increases (step #3). Next, it is determined whether the timer value is less than a predetermined timer threshold TH (step #4). The timer threshold TH is set in step #3 to a value at which the notch gain linked to the timer value of the notch timer reaches zero. If the timer value is less than the timer threshold TH, a first vibration suppression process (feedforward vibration suppression control) is executed using the gain adjusted in step #3 (step #5). If the timer value is equal to or greater than the timer threshold TH in step #4, the gain has decreased until the notch effect reaches zero. This means that the notch filter is essentially non-functional. Therefore, vibration suppression control is disabled (step #6).

[0067] After determining in step #4 that the timer value is equal to or greater than the timer threshold value TH, the notch timer may be stopped with the timer value held, or may continue incrementing until it is fixed at the maximum value. If the timer value is equal to or greater than the timer threshold value TH, the process branches from step #4 to step #6 while the torque command generation unit 11 continues to generate the PWM torque command Tpwm. Therefore, the notch filter does not act, and the vehicle control device 1 converts the PWM torque command Tpwm into the torque command T * The rotating electric machine 4 can be driven and controlled as a result.

[0068] The torque command T generated by the torque command generating unit 11 * However, when the PWM torque command Tpwm is switched to the normal torque command, the determination result in step #1 becomes No, and the timer value of the notch timer is reset to zero and stopped (step #2). Thereafter, if the normal command generation process continues, the notch timer remains stopped. Then, as described above with reference to FIG. 10 etc., the torque command generation unit 11 executes the second vibration suppression process (rotation speed feedback vibration suppression control). The second vibration suppression control is executed throughout the entire period in which the normal command generation process is executed.

[0069] The vehicle control device (1) described above will be briefly summarized below.

[0070] In one aspect, the vehicle drive device (1) is a vehicle control device (1) for controlling a vehicle equipped with a rotating electric machine (4) as a driving force source for wheels (W), and is configured to transmit a required torque (Tmg) to the wheels (W). * ) to the rotating electrical machine (4), * ) is the torque command (T * a torque command generating unit (11) that generates the required torque (Tmg * ) according to the torque command (T * (Tpwm)) and the discontinuous command generation process to generate the required torque (Tmg* ) is set to the torque command (T * ) and, when switching from the normal command generation process to the discontinuous command generation process, the torque command (T * ) is subjected to a first vibration damping process in which a notch filter is applied to reduce vibrations at a target frequency corresponding to a resonance frequency of a drive transmission mechanism (5) that transmits power between the rotating electric machine (4) and the wheels (W).

[0071] According to this configuration, the notch filter can effectively reduce vibrations due to resonance occurring in the drivetrain (5) when switching from a normal torque command, whose value changes continuously, to a torque command whose value changes discontinuously. Therefore, vehicle vibrations can be reduced, improving passenger comfort. In particular, the notch filter reduces vibrations at target frequencies corresponding to the resonant frequencies of the drivetrain (5). Therefore, even when the rotating electric machine (4) is driven based on a discontinuous torque command value, vibrations due to resonance occurring in the drivetrain (5) can be effectively reduced. That is, according to this configuration, torque fluctuations can be suppressed when switching between control based on a pulsed torque command and control based on a normal torque command, thereby reducing vibrations due to resonance occurring in the drivetrain (5).

[0072] In the vehicle control device (1), it is preferable that, in the first vibration suppression process, after switching from the normal command generation process to the discontinuous command generation process, the torque command generation unit (11) changes a gain (G) so as to gradually reduce the notch effect of the notch filter to zero.

[0073] When a notch filter is applied, the waveform of the discontinuous torque command becomes distorted, and the improvement in efficiency of the rotating electrical machine drive by using the discontinuous torque command may be limited or may even decrease. With this configuration, the gain (G) of the notch filter is gradually reduced, thereby shortening the time during which the notch filter is applied. Therefore, it is easy to obtain the effect of improving the energy efficiency of the rotating electrical machine control using the discontinuous torque command.

[0074] In the vehicle drive device (1), it is preferable that, after switching from the discontinuous command generation process to the normal command generation process, the torque command generation unit (11) executes a second vibration suppression process in which a torque in the opposite phase to the vibration of the drive transmission mechanism (5) is output to the rotating electric machine (4).

[0075] This configuration effectively reduces vibrations occurring in the drivetrain (5) even after switching from a discontinuous torque command to a normal continuous torque command, thereby reducing vehicle vibrations and improving passenger comfort.

[0076] In the vehicle drive device (1), the torque command generation unit (11) In the discontinuous command generation process, the torque command (T) is generated as a pulse width modulation waveform that switches between an ON state and an OFF state at a switching timing defined based on a control period (Pcnt) that is shorter than a set carrier period (Pca). * ), The pulse width modulation waveform is set in accordance with the rotation speed (ω) of the rotating electric machine (4), and a torque that falls within a high efficiency range (R1), which is an operating range in which the efficiency of the rotating electric machine (4) is higher than a predetermined specified value, is set by the torque command (T * ) value (Ton) and zero is generated as the value (Toff) for the pulse width modulated waveform off state.

[0077] According to this configuration, when the pulse width modulation waveform is in an on state, the rotating electric machine (4) is driven with a highly efficient torque, and when the pulse width modulation waveform is in an off state, the rotating electric machine (4) is driven so as not to output any torque, so that the rotating electric machine (4) can be driven efficiently. [Explanation of symbols]

[0078] 1: Vehicle control device, 4: Rotating electric machine, 5: Drive transmission mechanism, 11: Torque command generation unit, G: Gain, Pca: Carrier period, Pcnt: Control period, R1: First region (high efficiency range), T * : Torque command, Tmg * : required torque, W: wheel, Y: output, ω: rotation speed

Claims

1. A vehicle control device for controlling a vehicle equipped with a rotating electric machine as a driving force source for wheels, a torque command generation unit that generates, based on a required torque that is a torque that is required to be transmitted to the wheels, a torque command that is a command for causing the rotating electric machine to output the required torque, The torque command generation unit a discontinuous command generating process for generating a discontinuous command value as the torque command in accordance with the required torque; a normal command generation process for generating, as the torque command, a command value that continuously changes in accordance with the required torque; When switching from the normal command generation process to the discontinuous command generation process, the vehicle control device further executes a first vibration suppression process that applies a notch filter to the torque command to reduce vibrations of a target frequency corresponding to a resonance frequency of a drive transmission mechanism that transmits power between the rotating electric machine and the wheels.

2. 2. The vehicle control device according to claim 1, wherein, in the first vibration suppression process, after switching from the normal command generation process to the discontinuous command generation process, the torque command generation unit changes a gain so as to gradually reduce a notch effect of the notch filter to zero.

3. 3. The vehicle control device according to claim 1, wherein after switching from the discontinuous command generation process to the normal command generation process, the torque command generation unit executes a second vibration suppression process to cause the rotating electric machine to output a torque in an opposite phase to a vibration of the drive transmission mechanism.

4. The torque command generation unit In the discontinuous command generation process, the torque command is generated as a pulse width modulated waveform that switches between an ON state and an OFF state at a switching timing defined based on a control period shorter than a set carrier period, 3. The vehicle control device according to claim 1, wherein the pulse width modulation waveform is set in accordance with a rotation speed of the rotating electric machine, and a torque command value when the pulse width modulation waveform is in an ON state is a torque that falls within a high efficiency range, which is an operating range in which the efficiency of the rotating electric machine is higher than a predetermined specified value, and zero is generated as a value when the pulse width modulation waveform is in an OFF state.

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