Vehicle control device

Abstract

To reduce the torque error that occurs in a pulse-shaped torque command depending on the resolution of the control, and control a rotating electrical machine with an appropriate torque command according to the required torque.SOLUTION: A torque command generation unit of a vehicle control device executes a torque command generation process to generate a torque command Tpwm as a pulse width modulated waveform that switches between an ON state and an OFF state at a switching timing defined on the basis of the control period Pcnt, and when an error occurs between a basic duty ratio, which is the duty ratio of the ideal command Tpwm*, and an actual duty ratio, which is the duty ratio of the torque command Tpwm, further executes an error correction process to adjust the actual duty ratio in the carrier period Pca from the next period onwards in a direction to reduce the error in units of the control period Pcnt.SELECTED DRAWING: Figure 6

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] The above-described control device generally performs processing at a predetermined control period. Therefore, the change point of the pulse-shaped torque command is timed according to the control period. That is, the resolution of the pulse-shaped torque command depends on the control period. Therefore, the pulse-shaped torque command may have an error according to the resolution. For example, if this error causes a deviation in the output torque from the torque command, the ride comfort of the vehicle may be reduced.

[0005] In view of the above, it is desirable to reduce torque errors that occur in pulse-shaped torque commands depending on the resolution of control, and to control a rotating electrical machine with an appropriate torque command according to the required torque. [Means for solving the problem]

[0006] In view of the above, a vehicle control 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, and the torque command generation unit executes a torque command generation process that generates the torque command 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 that is shorter than a set carrier period, in a set carrier period, and if an error occurs between a basic duty ratio, which is the duty ratio of an ideal command that is set as a waveform that switches between an on state and an off state regardless of the control period in accordance with the required torque, and an actual duty ratio, which is the duty ratio of the torque command, further executes an error correction process that adjusts the actual duty ratio in the carrier period from the next period onwards in a direction that reduces the error in units of the control period.

[0007] With this configuration, even if an error occurs between the duty ratio of an ideal command corresponding to the required torque and the actual duty ratio of a pulse-width-modulated command due to the command being generated at a timing determined by the control period, the error can be prevented from accumulating. In other words, the error can be reduced over multiple carrier periods, and the average value of the torque command based on the actual duty ratio can be made closer to the average value of the torque command based on the ideal duty ratio. As a result, the error in the torque of the rotating electric machine relative to the required torque can be kept small. In this way, with this configuration, the torque error that occurs in the pulse-shaped torque command depending on the control resolution can be reduced, and the rotating electric machine can be controlled with an appropriate torque command corresponding to the required torque.

[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] Waveform diagram showing the principle of error correction processing [Figure 7] 1 is a flowchart showing an example of a torque command generation process including an error correction process; 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 equipped with only the rotating electric machine 4 as a driving force source for the wheels W is exemplified, but this does not preclude the vehicle from being a hybrid vehicle also equipped with an internal combustion engine.

[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 also becomes 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. * Therefore, the PWM basic command Tpwm * A time error Δt greater than or equal to zero and less than the control period Pcnt occurs between the on-duty Don of the PWM torque command Tpwm and the on-duty Don of the PWM torque command Tpwm. The on-torque value Ton, which is the value of the PWM torque command Tpwm in the on-state, is the high-efficiency torque Tef, so a torque error Δtrq as shown in the following equation (4) occurs in each carrier period Pca.

[0039] Δtrq = Δt·Ton = Δt·Tef···(4)

[0040] The PWM torque command Tpwm is a command value that includes this torque error Δtrq, so the PWM torque command Tpwm is * As a result, the torque command T * The torque of the rotating electrical machine 4 outputted in accordance with the required torque Tmg * An error occurs in the required torque Tmg. * If a discrepancy occurs between the output torque of the rotary electric machine 4 and the output torque of the rotary electric machine 4, the ride comfort of the vehicle may be reduced.

[0041] The vehicle control device 1 of this embodiment generates a pulse-like torque command T * By reducing the torque error Δtrq that occurs in * Appropriate torque command T * The rotating electrical machine 4 can be controlled by the above.

[0042] Here, the PWM basic command Tpwm * The duty ratio between the on-duty Don and the off-duty Doff of the PWM torque command Tpwm is referred to as the basic duty ratio, and the duty ratio between the on-duty Don and the off-duty Doff of the PWM torque command Tpwm is referred to as the actual duty ratio. If an error (time error Δt) occurs between the basic duty ratio and the actual duty ratio, the torque command generator 11 further executes an error correction process to adjust the actual duty ratio in the carrier period Pca from the next period onward in a direction to reduce the error (time error Δt) in units of the control period Pcnt. Since it is preferable for the error to converge quickly, it is preferable to adjust the actual duty ratio in the carrier period Pca of the next period in a direction to reduce the time error Δt.

[0043] The principle of the error correction process will be described with reference to Fig. 6. Fig. 6 shows, from top to bottom, (1) PWM average command value Tpwm0 * and PWM basic command Tpwm * 6 shows (1) the PWM torque command Tpwm before error correction processing is performed, (2) the PWM torque command Tpwm before error correction processing is performed, (3) the torque error Δtrq and the average value Δtrq_av of the torque error Δtrq in that case, (4) the PWM torque command Tpwm after error correction processing is performed, and (5) the torque error Δtrq and the average value Δtrq_av of the torque error Δtrq in that case. Figure 6 shows an example of carrier periods Pca for two periods, the first period P1 and the second period P2.

[0044] The torque error Δtrq of the PWM torque command Tpwm for which the error correction process has not been performed occurs in a direction that reduces the torque in both the first period P1 and the second period P2. Therefore, the average value Δtrq_av of the torque error Δtrq throughout the first period P1 and the second period P2 is also a negative value.

[0045] In the PWM torque command Tpwm after the error correction process, a torque error Δtrq occurs in the first period P1 in a direction that reduces the torque. That is, a time error Δt occurs between the basic duty ratio and the actual duty ratio in the first period P1. Then, the actual duty ratio in the carrier period Pca from the next period onwards, in this case the second period P2, which is the next carrier period Pca, is adjusted in a direction that reduces the time error Δt in units of the control period Pcnt (in this case, in a direction that extends the on-duty Don). Because the on-duty Don is lengthened in units of the control period Pcnt, the on-duty Don is adjusted in units of the PWM basic command Tpwm * The on-duty period Don is longer than that of the first period P1. Therefore, in the second period P2, a torque error Δtrq occurs in the direction in which the torque increases. For this reason, the average value Δtrq_av of the torque error Δtrq throughout the first period P1 and the second period P2 is almost zero. In other words, the error is reduced by executing the error correction process.

[0046] 7 shows an example of a torque command generation process including an error correction process. In step #1, the torque command generation unit 11 generates a PWM basic command Tpwm as described above using equation (2). * The on-duty Don of the PWM torque command Tpwm is calculated as the counter value CNT by dividing the on-duty Don by the control period Pcnt.

[0047] In the next step #2, the torque error Δtrq is calculated. The integral value of the PWM torque command Tpwm in the carrier period Pca is the value obtained by multiplying the on-torque value Ton (here, the high-efficiency torque Tef) by the on-duty Don (=counter value CNT). * The integral value of the PWM average command value Tpwm0 * The integral value of the PWM torque command Tpwm in the carrier cycle Pca and the PWM basic command Tpwm in the carrier cycle Pca are *The difference between this and the integral value of is the torque error Δtrq. This torque error Δtrq is preferably stored in a primary storage unit such as a register, since it will be used for determination in the carrier cycle Pca from the next cycle onwards.

[0048] In the next step #3, it is determined whether the torque error Δtrq stored in a primary storage unit such as a register, i.e., the torque error Δtrq in the carrier cycle Pca one or more years before, exceeds the torque error determination threshold Tth. If the torque error Δtrq to be determined is equal to or less than the torque error determination threshold, the on-duty Don is not adjusted, and the PWM torque command Tpwm is generated by the on-duty Don (=CNT) calculated in step #1. This PWM torque command Tpwm is used to generate the torque command T * is output as

[0049] If the torque error Δtrq to be determined exceeds the torque error determination threshold, the on-duty Don is adjusted. In this embodiment, because the torque error Δtrq appears in the negative direction, the counter value CNT is incremented by 1 (step #4). This increases the on-duty Don by one control period Pcnt, increases the torque integral value over the carrier period Pca, and adjusts the torque error Δtrq in a decreasing direction. In other words, if a torque error Δtrq occurs between the torque indicated by the basic duty ratio and the torque indicated by the effective duty ratio, an error correction process is further executed to adjust the effective duty ratio in the carrier period Pca from the next period onward in a direction to reduce the torque error Δtrq in units of the control period Pcnt.

[0050] As shown in equation (3), the torque error Δtrq is the product of the time error Δt and the on-torque value Ton (high-efficiency torque Tef). Even if the time error Δt is the same value, if the on-torque value Ton is different, the value of the torque error Δtrq will also be different. Therefore, in order to suppress fluctuations in the output torque of the rotating electric machine 4, it is preferable to determine the torque error Δtrq in step #3, as described above. However, this does not prevent the time error Δt from being determined in step #3.

[0051] PWM basic command Tpwm * and the PWM average command value Tpwm0 * That is, since the on-torque value Ton is the same, whether the determination is for the torque error Δtrq or the time error Δt, the determination is still whether an error has occurred between the basic duty ratio and the actual duty ratio. Therefore, the error correction process can be said to be a process that, when an error has occurred between the basic duty ratio and the actual duty ratio, adjusts the actual duty ratio in the carrier period Pca from the next period onwards in a direction to reduce the error in units of the control period Pcnt.

[0052] Other embodiments will be described below. Note that the configurations of the embodiments described below are not limited to being applied independently, and can also be applied in combination with the configurations of other embodiments as long as no contradiction occurs.

[0053] (1) In the above example, the torque command generating unit 11 is configured to be able to selectively execute the discontinuous command generating process (pulse width modulation command generating process) and the normal command generating process as the torque command generating process. However, the normal command generating process is executed when the required torque Tmg * is used as the torque command T * Alternatively, the torque command generating unit 11 may be configured to execute only the discontinuous command generating process (pulse width modulation command generating process) as the torque command generating process.

[0054] (2) In the above, an example has been described in which the on-duty Don is extended in the error correction process. However, if the torque error Δtrq is an error that increases the torque, the off-duty Doff may be adjusted to be extended (the on-duty Don may be reduced).

[0055] As described above with reference to equation (3), the counter value CNT for setting the on-duty Don of the PWM torque command Tpwm is calculated by a round-down calculation. However, this does not preclude the counter value CNT from being calculated by a round-up calculation or a round-off calculation.

[0056] The vehicle control device (1) described above will be briefly summarized below.

[0057] In one aspect, the vehicle control 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 calculate a required torque (Tmg) which is a torque required to be transmitted to the wheels (W). * ) to the rotating electrical machine (4), * ) is the torque command (T * The torque command generation unit (11) generates the torque command (T) as a pulse width modulation waveform (Tpwm) 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 carrier period (Pca) in a set carrier period (Pca). * ) is generated, and the required torque (Tmg * ) is set as a waveform that switches between the ON state and the OFF state regardless of the control period (Pcnt). * ) and the torque command (T * If an error occurs between the actual duty ratio, which is the duty ratio of the carrier period (Pca) (Tpwm), and the actual duty ratio, the error correction process is further executed to adjust the actual duty ratio in the carrier period (Pca) from the next period onwards in a direction to reduce the error in units of the control period (Pcnt).

[0058] According to this configuration, the command is generated at a timing determined by the control cycle (Pcnt), and therefore the required torque (Tmg *Even if an error occurs between the duty ratio of the ideal command according to the duty ratio of the pulse width modulated command (Tpwm) and the actual duty ratio of the pulse width modulated command (Tpwm), the error can be prevented from accumulating. In other words, when viewed over multiple carrier periods (Pca), the error can be reduced, and the average value of the torque command (Tpwm) based on the actual duty ratio can be adjusted to the torque command (Tpwm) based on the ideal duty ratio. * As a result, the required torque (Tmg * ) can be reduced. In this way, according to this configuration, the torque error of the rotating electrical machine (4) relative to the pulse-shaped torque command (T * ) to reduce the torque error (Δtrq) that occurs in the required torque (Tmg * ) according to the appropriate torque command (T * ) can control the rotating electric machine (4).

[0059] The vehicle control device (1) is configured such that the torque command generation unit (11) generates a torque (Tef) that is set in accordance with the rotation speed of the rotating electric machine (4) and falls within a high efficiency range (R1) in which the efficiency of the rotating electric machine (4) is higher than a predetermined specified value, based on the torque command (Tef) when the pulse width modulation waveform is in an on state. * ) value (Ton), and zero is the torque command (T * ) is preferably set as the value (Toff).

[0060] 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 (Tef), 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.

[0061] The vehicle control device (1) is configured with a plurality of switching elements, and controls an inverter (7) that converts power between the AC rotating electric machine (4) and a DC power source (6) by controlling the torque command (T *), and when the pulse width modulation waveform is in the off state, all the switching elements of the inverter (7) are controlled to be in the off state, thereby shutting down the inverter (7).

[0062] According to this configuration, when the pulse width modulation waveform is in an OFF state, the inverter (7) is shut down and controlled, thereby reducing power consumption, and therefore the rotating electric machine (4) can be driven efficiently.

[0063] The vehicle control device (1) is configured such that the carrier period (Pca) is equal to or smaller than the torque command (T * It is preferable that the torque fluctuation of the rotating electric machine (4) driven and controlled by the torque converter (4) is set to a period that is not perceptible by the passengers of the vehicle.

[0064] Torque command (T * Even if torque fluctuations occur according to the carrier period (Pca) by making the carrier period (Pca) a pulse width modulated waveform, the torque fluctuations can be prevented from being perceived by the occupants by appropriately setting the carrier period (Pca). Therefore, it is possible to achieve both highly energy-efficient driving of the rotating electric machine (4) and a comfortable ride for the occupants. [Explanation of symbols]

[0065] 1: Vehicle control device, 4: Rotating electric machine, 6: DC power supply, 7: Inverter, 11: Torque command generation unit, Pca: Carrier period, Pcnt: Control period, R1: First region (high efficiency range), T * : Torque command, Tef: High efficiency torque (torque in which the efficiency of the rotating electrical machine is in the high efficiency range), Tmg * : Required torque, Toff: Off torque value (torque command value when pulse width modulation waveform is off), Ton: On torque value (torque command value when pulse width modulation waveform is on), Tpwm: PWM torque command (torque command generated as pulse width modulation waveform) Tpwm * : PWM basic command (ideal command), W: Wheel

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 executes a torque command generation process for generating the torque command 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 that is shorter than the set carrier period; and when an error occurs between a basic duty ratio, which is the duty ratio of an ideal command set as a waveform that switches between an on state and an off state regardless of the control period in accordance with the required torque, and an actual duty ratio, which is the duty ratio of the torque command, further executing an error correction process to adjust the actual duty ratio in the carrier period from the next period onwards in a direction that reduces the error in units of the control period.

2. 2. The vehicle control device according to claim 1, wherein the torque command generation unit is set according to a rotation speed of the rotating electric machine, and sets the torque command value when the pulse width modulation waveform is in an on state to 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 sets zero as the torque command value when the pulse width modulation waveform is in an off state.

3. an inverter including a plurality of switching elements for converting power between the AC rotating electric machine and a DC power source, the inverter controlling the switching of the inverter based on the torque command; 3. The vehicle control device according to claim 2, wherein when the pulse width modulation waveform is in an OFF state, all of the switching elements of the inverter are controlled to be in an OFF state, thereby shutting down the inverter.

4. 4. The vehicle control device according to claim 1, wherein the carrier period is set to a period in which torque fluctuations of the rotating electric machine, which is drive-controlled by the torque command of the pulse-width modulated waveform, are not perceived by an occupant of the vehicle.

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