Vehicle control device

Abstract

To appropriately achieve improved energy efficiency through drive control of a rotating electric machine based on pulsed torque commands, and high responsiveness of torque output by the rotating electric machine to requested torque.SOLUTION: A torque command generation part of a vehicle control device selectively executes discontinuous command generation processing PWM, which generates discontinuous command values as torque commands according to requested torque, and normal command generation processing Normal, which generates continuously varying command values as torque commands according to the requested torque. When a change rate ΔTmg in the requested torque becomes equal to or greater than a first threshold THtmg during execution of the discontinuous command generation processing PWM, the torque command generation part terminates the discontinuous command generation processing PWM and executes the normal command generation processing Normal.SELECTED DRAWING: Figure 10

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 discontinuous torque command (pulse-shaped torque command) 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) in 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 pulse-shaped torque command described above generally has a peak value and duty cycle determined for each carrier cycle. The average value of the pulse-shaped torque command in one carrier cycle corresponds to the average value of the required torque in that carrier cycle. When the required torque value changes little, the value also fluctuates little over the carrier cycle, so the average value of the pulse-shaped torque command in the same carrier cycle and the average value of the required torque are roughly the same. On the other hand, when the required torque value changes greatly, the value changes greatly over the carrier cycle, so a difference is likely to occur between the average value of the pulse-shaped torque command in the same carrier cycle and the average value of the required torque. As a result, the vehicle's behavior in accordance with the required torque cannot be achieved with high responsiveness, which may lead to a deterioration in ride comfort.

[0005] Therefore, it is desirable to appropriately achieve improved energy efficiency by controlling the drive of a rotating electrical machine based on a pulsed torque command, and high responsiveness of the torque output by the rotating electrical machine in response to a required torque. [Means for solving the problem]

[0006] In view of the above, a vehicle control device is provided 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 a torque that is required to be transmitted to the wheels, and the torque command generation unit selectively executes a discontinuous command generation process that generates, as the torque command, a discontinuous command value according to the required torque, and a normal command generation process that generates, as the torque command, a command value that changes continuously according to the required torque, and in the discontinuous command generation process, the torque command generation unit generates the torque command as a pulse width modulated waveform that switches between an on state and an off state within a set carrier period, and determines a duty of the pulse width modulated waveform for each carrier period, and when a rate of change of the required torque becomes equal to or greater than a predetermined first threshold value during execution of the discontinuous command generation process, the torque command generation unit terminates the discontinuous command generation process and executes the normal command generation process.

[0007] According to this configuration, when the rate of change of the required torque becomes equal to or greater than a first threshold, the torque command generation process is switched from the discontinuous command generation process to the normal command generation process. Therefore, even when the rate of change of the required torque is high, the responsiveness of the torque output by the rotating electric machine to the required torque can be ensured. Furthermore, according to this configuration, when the rate of change of the required torque is less than the first threshold, the rotating electric machine is driven and controlled using the torque command generated by the discontinuous command generation process, thereby intermittently operating the rotating electric machine and improving the energy efficiency of the vehicle. In other words, according to this configuration, it is possible to appropriately achieve both improved energy efficiency through drive control of the rotating electric machine based on a pulsed torque command and high responsiveness of the torque output by the rotating electric machine 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] A time chart showing the relationship between the rate of change of the required torque and the average command value per carrier cycle in the PWM command generation process. [Figure 7] 1 is a time chart showing an example of a carrier period that is variable with respect to the rate of change of the required torque, and showing an example of the relationship between the rate of change of the required torque and the type of torque command generation process; [Figure 8]FIG. 10 is a diagram illustrating the relationship between the carrier period, the rate of change of the required torque, and the type of torque command generation process. [Figure 9] FIG. 10 is a diagram showing an example of a variable range of a carrier period. [Figure 10] A flowchart showing an example of a procedure for switching between a PWM command generation process and a normal command generation 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. * 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] As described above with reference to FIG. 5, the on-torque value Ton and duty of the PWM torque command Tpwm are determined for each carrier period Pca. * Average value of (= PWM average command value Tpwm0 * ) is the required torque Tmg in the carrier cycle * Therefore, excluding the error due to the resolution of the control period Pcnt, the average value of the PWM torque command Tpwm is also roughly the same as the required torque Tmg *corresponds to the average value of

[0041] As shown in the carrier cycles Pca (first cycle P1, second cycle P2, sixth cycle P6, and seventh cycle P7) on the left and right sides of FIG. 6, the required torque Tmg * When the change in the value of is small, the change in the value in the carrier cycle Pca is also small, so the PWM basic command Tpwm * Average value of (= PWM average command value Tpwm0 * ) and the required torque Tmg * Therefore, the average value of the PWM torque command Tpwm is also approximately the same as the average value of the required torque Tmg within the error range due to the resolution of the control period Pcnt. * This is roughly the same value as the average value of

[0042] On the other hand, as shown in the center carrier cycle Pca (third cycle P3, fourth cycle P4, fifth cycle P5) of FIG. 6, the required torque Tmg * When the change in the value of is large, the value changes significantly in the carrier cycle Pca, so the PWM basic command Tpwm * Average value of (= PWM average command value Tpwm0 * ) and the required torque Tmg * In Fig. 6, a difference is likely to occur between the average value of the required torque Tmg * and the PWM average command value Tpwm0 * The area of ​​the triangle formed between * Average value of (= PWM average command value Tpwm0 * ) and the required torque Tmg * Therefore, the required torque Tmg * If the change in the value of is large, the PWM torque command Tpwm is set to the torque command T * In this case, the required torque Tmg * The error between the required torque Tmg and the output torque of the rotating electrical machine 4 increases. * This may result in the vehicle not being able to behave responsively in response to the vehicle's movements, leading to a decrease in ride comfort.

[0043] Therefore, the vehicle control device 1 of this embodiment improves energy efficiency by controlling the drive of the rotating electrical machine 4 based on the PWM torque command Tpwm, and * The rotary electric machine 4 is configured to appropriately realize high responsiveness of the torque outputted by the rotary electric machine 4 in response to the rotation of the rotary electric machine 4 .

[0044] As described above, the torque command generator 11 calculates the required torque Tmg * The torque command T * PWM command generation process (discontinuous command generation process) that generates the required torque Tmg * The torque command T * During the execution of the PWM command generation process, the torque command generation unit 11 selectively generates the required torque Tmg * When the rate of change ΔTmg (see FIGS. 8 and 10) of the PWM command is equal to or greater than a first threshold value THtmg (see FIG. 10), the PWM command generation process is terminated and a normal command generation process is executed. The first threshold value THtmg may be a fixed value or a variable value.

[0045] In this embodiment, as shown in FIG. 7, the torque command generating unit 11 generates the required torque Tmg * 6 and 7, the carrier period Pca is shortened as the rate of change ΔTmg of the required torque Tmg increases. * Since the rate of change ΔTmg of the required torque Tmg is small, the carrier period Pca is the first carrier period Pca1 of the standard length. * Because the rate of change ΔTmg of the carrier period Pca is large, the carrier period Pca is the second carrier period Pca2, which is shorter than the first carrier period Pca1. For ease of understanding, an example is shown in which the second carrier period Pca2 is half the duration of the first carrier period Pca1. That is, the third period P3 is divided into two periods "P31" and "P32," and the fourth period P4 is divided into two periods "P41" and "P42."

[0046] Here, the required torque Tmg * In the illustrated example, the carrier period Pca is shortened in two stages as the rate of change ΔTmg of the required torque Tmg increases, but it may be shortened in three or more stages. * As the rate of change ΔTmg of the carrier period Pca increases, the carrier period Pca may be shortened in a stepwise manner or continuously. Even when the carrier period Pca is changed continuously, it is changed in units of the control period Pcnt.

[0047] Required torque Tmg * The rate of change ΔTmg of the required torque Tmg increases. * Torque command T according to * Therefore, the duty ratio of the torque command T generated by the PWM command generation process can be updated more frequently. * Even when the rotating electrical machine 4 is driven and controlled based on the required torque Tmg * The torque command generator 11 generates the required torque Tmg during the PWM command generation process. * Even if the rate of change ΔTmg of the PWM command generation process increases, the responsiveness can be maintained by shortening the carrier period Pca, so that the timing for terminating the PWM command generation process and executing the normal command generation process can be delayed, and drive control of the rotating electric machine 4 can be executed for a longer period of time in an energy-efficient state.

[0048] Of course, the carrier period Pca may be constant rather than variable. From the viewpoint of energy efficiency, it is preferable that the carrier period Pca is variable. However, it is preferable that the required torque Tmg * The required torque Tmg due to the increase in the rate of change ΔTmg * and the output torque of the rotary electric machine 4 can be suppressed by switching the torque command generation process.

[0049] In the example shown in FIG. 7, the required torque Tmg is greater than that in the third period P3 and the fourth period P4. * In the fifth period P5, where the rate of change ΔTmg of the required torque Tmg is large, the length of the carrier period Pca is the standard first carrier period Pca1. There is a limit to how much the carrier period Pca can be shortened, and in the fifth period P5, the carrier period Pca cannot be shortened. Therefore, the torque command generation process is switched from the PWM command generation process (PWM) to the normal command generation process (Normal) without changing the carrier period Pca. That is, in the fifth period P5, the required torque Tmg * Since the rate of change ΔTmg of the PWM command is equal to or greater than the first threshold value THtmg, the PWM command generation process (PWM) is terminated and the normal command generation process (Normal) is executed.

[0050] Furthermore, the required torque Tmg * The switching of the torque command generation process according to the rate of change ΔTmg of the required torque Tmg is also correlated with the carrier period Pca. * The carrier period Pca, which shortens as the rate of change ΔTmg of the carrier period Pca increases, also has a limit to how much it can be shortened, and the length of the carrier period Pca at this limit is called the lower limit period THpca. * The torque command generating unit 11 calculates the change rate ΔTmg of the required torque Tmg during the execution of the PWM command generating process. * When the carrier period Pca, which becomes shorter as the rate of change ΔTmg of the PWM command increases, becomes equal to or shorter than the lower limit period THpca, the PWM command generation process can be terminated and the normal command generation process can be executed.

[0051] Figure 9 shows an example of the variable range of the carrier period Pca. *The PWM torque command Tpwm generated based on the carrier period Pca increases from the off-torque value Toff to the on-torque value Ton and decreases from the on-torque value Ton to the off-torque value Toff with a gradient determined by the torque rate ([Nm / s]). When the carrier period Pca is shortened, the periods of the on-duty Don and the off-duty Doff become shorter even if the duty ratio, which is the ratio of the on-duty Don to the off-duty Doff within the carrier period Pca, remains the same. For this reason, as in the third carrier period Pca3 shown in FIG. 9, there are cases where the off-torque value Toff cannot increase from the off-torque value Toff to the on-torque value Ton within the on-duty Don period, or where the on-torque value Ton cannot decrease from the on-torque value Ton to the off-torque value Toff within the off-duty Doff period. The lower limit period THpca is set based on this principle.

[0052] The procedure for switching between the PWM command generation process and the normal command generation process will be described below with reference to the flowchart in Fig. 10. First, the required torque Tmg * It is determined whether the absolute value of the rate of change ΔTmg of the required torque Tmg is less than a first threshold value THtmg (#1). * This is because there is a possibility that the torque command T may decrease. If the rate of change ΔTmg is less than the first threshold value THtmg, it is determined whether or not the execution condition for the PWM command generation process is satisfied (#2). In this embodiment, the execution condition for the PWM command generation process is that the traction control (TRC) or the antilock brake system (ABS) is not operating. If the traction control or the antilock brake system is operating, there is a possibility that the rate of change ΔTmg may intermittently exceed the first threshold value THtmg or fall below the first threshold value THtmg. If the method of the torque command generation process is frequently switched in such a case, the torque command T * The stability of the control of the rotary electric machine 4 based on the above is impaired. Therefore, the execution conditions are determined as described above.

[0053] If it is determined in step #2 that the execution conditions for the PWM command generation process are met, then the required torque Tmg * The carrier period Pca is calculated based on the rate of change ΔTmg of the carrier torque (#3). Next, it is determined whether the calculated carrier period Pca is longer than the lower limit period THpca (#4). If the carrier period Pca is longer than the lower limit period THpca, the required torque Tmg * Based on the calculated carrier period Pca, a PWM command generation process (PWM) is executed (#5).

[0054] In step #1, the required torque Tmg * If it is determined that the absolute value of the rate of change ΔTmg of the carrier period Pca is equal to or greater than the first threshold value THtmg, the normal command generation process (Normal) is executed (#6). Also, if it is determined in step #4 that the carrier period Pca is equal to or less than the lower limit period THpca, the normal command generation process (Normal) is executed (#6).

[0055] During the execution of the normal command generation process (Normal), the torque command generation unit 11 generates the required torque Tmg * When the rate of change ΔTmg of the required torque Tmg becomes less than the first threshold value THtmg, the normal command generation process (Normal) is terminated and the PWM command generation process (PWM) is executed, as shown in the fifth cycle P5 to the sixth cycle P6 in Fig. 7. However, if the same first threshold value THtmg is used in switching from the PWM command generation process (PWM) to the normal command generation process (Normal) and in switching from the normal command generation process (Normal) to the PWM command generation process (PWM), the required torque Tmg * When the rate of change ΔTmg of torque command generation processing is close to the first threshold value THtmg, the method of torque command generation processing may be frequently switched. For this reason, when switching from normal command generation processing (Normal) to PWM command generation processing (PWM), it is preferable to use a second threshold value set to be equal to or lower than the first threshold value THtmg as the judgment criterion.

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

[0057] In view of the above, 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 * a torque command generating unit (11) that generates the required torque (Tmg * ) according to the torque command (T * ) and the required torque (Tmg * ) is set to the torque command (T * ) as a pulse width modulation waveform that switches between an ON state and an OFF state within a set carrier period (Pca), and the torque command generation unit (11) selectively executes a normal command generation process (Normal) that generates the torque command (T * ), and determines the duty of the pulse width modulation waveform for each carrier period (Pca), and the torque command generation unit (11) determines the required torque (Tmg * When the rate of change (ΔTmg) of the pulse width (V ...

[0058] According to this configuration, the required torque (Tmg * When the rate of change (ΔTmg) of the torque command (T * ) generation process is switched from discontinuous command generation process (PWM) to normal command generation process (Normal). * Even if the rate of change (ΔTmg) of the required torque (Tmg *) can be ensured. * When the rate of change (ΔTmg) of the torque command (T * ) to drive and control the rotating electric machine (4), the rotating electric machine (4) can be operated intermittently, thereby improving the energy efficiency of the vehicle. That is, according to this configuration, the energy efficiency can be improved by driving and controlling the rotating electric machine (4) based on the pulse-shaped torque command, and the required torque (Tmg * ) can appropriately realize high responsiveness of the torque output by the rotary electric machine (4).

[0059] Further, the torque command generating unit (11) controls the required torque (Tmg * It is preferable to shorten the carrier period (Pca) continuously or stepwise as the rate of change (ΔTmg) of the carrier period (Pca) increases.

[0060] According to this configuration, the required torque (Tmg * The rate of change (ΔTmg) of the required torque (Tmg) increases, and therefore the carrier period (Pca) becomes shorter. * The rate of change (ΔTmg) of the required torque (Tmg * ) torque command (T * ) duty ratio can be updated more frequently. * Even if the rotating electric machine (4) is driven and controlled based on the required torque (Tmg * ) can improve the responsiveness of the torque output by the rotating electrical machine (4).

[0061] Further, in the discontinuous command generation process (PWM), the torque command generation unit (11) generates a torque that is set according to 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, in response to the torque command (T * ) is a value (Ton) of the pulse width modulation waveform, and zero is a value (Toff) of the pulse width modulation waveform in an off state. The first threshold value (THtmg) is the required torque (Tmg) corresponding to the shortest carrier period (Pca) at which the pulse width modulation waveform can change from an off state to an on state and from an on state to an off state. * It is preferable that the value be set to a value equal to or greater than the rate of change (ΔTmg) of the temperature change (Tmax ...).

[0062] According to this configuration, within a range where a pulse width modulation waveform can be appropriately formed, a torque command (T * ) is generated. Therefore, the rotating electric machine (4) is driven and controlled based on the pulse-like torque command as much as possible, thereby improving energy efficiency, and also easily ensuring high responsiveness of the output torque of the rotating electric machine (4) to the required torque.

[0063] Further, the torque command generating unit (11) generates the required torque (Tmg * When the rate of change (ΔTmg) of the pulse width change (PWM) of the pulse width change (PWM) becomes less than a second threshold value that is set equal to or less than the first threshold value (THtmg), it is preferable to terminate the normal command generation process (Normal) and execute the discontinuous command generation process (PWM).

[0064] According to this configuration, the required torque (Tmg * ) change rate (ΔTmg) is high, and the torque command (T * ) is generated, the required torque (Tmg *When the rate of change (ΔTmg) of the torque (torque) (kΩ) becomes low, the process can be switched to the discontinuous command generation process (PWM). Therefore, according to this configuration, it is easy to appropriately improve the energy efficiency when controlling the drive of the rotating electric machine (4) and ensure the responsiveness of the torque output by the rotating electric machine (4). [Explanation of symbols]

[0065] 1: Vehicle control device, 4: Rotating electric machine, 11: Torque command generation unit, Pca: Carrier period, R1: First region (high efficiency range), T * : torque command, THtmg: first threshold value, Tef: high-efficiency torque (torque that puts the efficiency of the rotating electrical machine in a high-efficiency range, which is an operating range in which the efficiency is higher than a predetermined specified value), 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), W: Wheel, ΔTmg: Rate of change

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; the torque command generation unit generates the torque command as a pulse width modulation waveform that switches between an on state and an off state within a set carrier period in the discontinuous command generation process, and determines a duty of the pulse width modulation waveform for each carrier period; When a rate of change of the required torque becomes equal to or greater than a predetermined first threshold value during execution of the discontinuous command generation process, the torque command generation unit terminates the discontinuous command generation process and executes the normal command generation process.

2. The vehicle control device according to claim 1 , wherein the torque command generating unit shortens the carrier period continuously or stepwise as the rate of change of the required torque increases during the discontinuous command generating process.

3. the torque command generation unit, in the discontinuous command generation process, sets a torque that is set according to the rotation speed of the rotating electric machine and 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, as the torque command value when the pulse width modulation waveform is in an ON state, and sets zero as the value when the pulse width modulation waveform is in an OFF state; 3. The vehicle control device according to claim 2, wherein the first threshold value is set to a value equal to or greater than a rate of change of the required torque corresponding to the shortest carrier period during which the pulse width modulation waveform can change from an off state to an on state and from an on state to an off state.

4. 4. The vehicle control device according to claim 1, wherein, when a rate of change of the required torque becomes less than a second threshold value that is set to be equal to or less than the first threshold value during execution of the normal command generation process, the torque command generation unit terminates the normal command generation process and executes the discontinuous command generation process.

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