JP2010193542A - Shift controller for vehicles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shift controller for vehicles wherein a shift time can be shortened. <P>SOLUTION: The shift controller includes a motor 1, a transmission 3 that changes the number of revolutions of the motor 1 and outputs it to a driving wheel 5, a clutch 2 that is placed between the motor 1 and the transmission 3 and is disengaged when the transmission 3 starts a shift and is engaged after the completion of a shift an inverter 10 that carries out pulse width modulation control at a predetermined carrier frequency and supplies power to the motor 1, and a carrier frequency change determination unit 32 that changes the carrier frequency to a value higher than a carrier frequency before a shift request when the shift request for the transmission 3 is output and changes it to a value lower than the carrier frequency during a shift after the completion of the shift. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transmission control device for a vehicle.

  Conventionally, a technique described in Patent Document 1 is known as shift control for a vehicle that travels using a motor as a drive source. This gazette has a high response mode and a low response mode for motor control, and prohibits switching of the motor control mode during shifting of the transmission, thereby suppressing sudden changes in the motor operating state. Yes.

JP 2006-117206 A

  However, in the technique described in Patent Document 1, if the speed change is performed while the low-response mode is selected, it is necessary to change the rotation speed of the motor during the speed change. There was a problem of becoming longer.

  The present invention has been made paying attention to the above problem, and an object of the present invention is to provide a vehicle shift control device that can shorten the shift time.

  In order to achieve the above object, in the present invention, the carrier frequency output from the inverter is set higher during non-shifting during shifting of the transmission.

  Therefore, during the shift, the number of switching operations in the pulse width modulation control can be increased, so that the current control accuracy and thus the control accuracy of the motor can be improved, and the shift time can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system diagram of a transmission control device for a vehicle according to a first embodiment. 3 is a flowchart illustrating a carrier frequency change process according to the first embodiment. 3 is a time chart illustrating carrier frequency change processing according to the first exemplary embodiment. It is the schematic showing the vehicle structure of another Example. It is the schematic showing the vehicle structure of another Example.

  FIG. 1 is an overall system diagram of a vehicle according to a first embodiment to which the present invention is applied. The vehicle according to the first embodiment is an electric vehicle, and the driving force of the motor 1 is changed by the transmission 3, and the driving force is transmitted from the differential gear 4 to the driving wheels 5 to travel.

  The motor 1 converts electric power (direct current) stored in the battery 20 into motor driving power by the inverter 10 and outputs driving power. On the other hand, at the time of deceleration or the like, the motor 1 is operated as a generator, and the generated power is converted into DC power by the inverter 10 to charge the battery 20. When driving the motor 1, the inverter 10 outputs a pseudo sine wave by pulse width modulation control, and sets a desired output state within a predetermined range. Note that, when performing pulse width modulation control, optimal control is performed by appropriately changing the carrier frequency. This carrier frequency means the frequency of the modulated wave for determining the pulse width of the output voltage type by the inverter. If the carrier frequency is high, the control can be executed finely. If the carrier frequency is low, concerns such as heat generation are suppressed by reducing the number of switching of the element, but it can be said that the control is not fine.

  A clutch 2 is provided between the motor 1 and the transmission 3 to connect / disconnect the driving force of the motor 1 to / from the input shaft of the transmission 3. The clutch 2 is released when the transmission 3 shifts, and is completely engaged in a steady state other than the shift. Note that slip control is performed according to the required driving force and operating conditions of the motor 1 to suppress a shock at the time of clutch engagement / disengagement, and the driving efficiency of the motor 1 is increased.

  The transmission 3 is a stepped automatic transmission. In the first embodiment, an always-meshing automatic transmission is adopted. Specifically, it has an actuator that fixes one of a plurality of fixed mesh ratios such as 1st speed and 2nd speed in the power transmission path among the constantly meshing gear sets, and is determined by a shift determination unit 31 described later. The actuator is operated to change the gear ratio so that the changed gear ratio is obtained.

  The controller 30 includes an accelerator opening sensor 42 that detects an accelerator pedal opening that is operated by a driver, a vehicle speed sensor 41 that detects a vehicle speed, and a temperature sensor 43 that detects an inverter module temperature representing a heat generation state of the inverter 10. Input sensor signal. The shift determination unit 31 has a preset map, determines a gear ratio based on the vehicle speed and the accelerator opening, and outputs a shift request.

  The carrier frequency variable determining unit 32 (frequency changing unit, frequency limiting unit) determines a pulse width based on a shift request command from the shift determining unit 31, a clutch state quantity from a clutch control unit 34 to be described later, and an inverter module temperature. A carrier frequency for performing modulation control is determined, and a carrier frequency command is output to the motor control unit 33. If the inverter module temperature is equal to or higher than a predetermined value set in advance, the carrier frequency is limited to a lower predetermined frequency, and if it is lower than the predetermined value, a high predetermined frequency that is not particularly limited is output (frequency limiting means). When the inverter module temperature is equal to or higher than a predetermined value and a shift request command is output, the carrier frequency increase amount determination process is performed to change to a higher carrier frequency, and the shift is completed based on the clutch state amount. If it is determined that the carrier frequency is decreased, the carrier frequency is changed to a lower carrier frequency, and the carrier frequency corresponding to the inverter temperature is output (frequency changing means).

  FIG. 2 is a flowchart showing the carrier frequency variable determination process. In step 101, it is determined whether or not there is a shift request. If there is a shift request, the process proceeds to step 102. Otherwise, this control flow is terminated. In step 102, the inverter module temperature is detected, and a carrier frequency increase amount determination process is executed. In step 103, it is determined whether or not the shift process is completed based on the clutch state quantity. If it is determined that the shift process is completed, the process proceeds to step 104. Otherwise, the control flow is terminated. In step 104, the inverter module temperature is detected, and a carrier frequency reduction amount determination process is executed. At this time, if the inverter module temperature is low, the carrier frequency reduction amount may be small, and the control may be continued with a high carrier frequency. On the other hand, if the carrier module temperature is high, the carrier frequency reduction amount is set large.

  The motor control unit 33 performs torque control based on the accelerator opening detected by the accelerator opening sensor 42, and outputs torque according to the required driving force. Further, when the shift request signal is received, the clutch 2 is released as will be described later. At this time, as the clutch 2 is released, the load on the motor 1 may decrease at a stretch, and the rotational speed may increase rapidly. Therefore, when the shift request signal is received, the torque control according to the current accelerator pedal opening degree is switched to the blow-up prevention torque control for suppressing the rapid increase in the rotational speed, and the target motor torque is reduced.

  On the other hand, since the rotational speed of the drive wheel 5 does not change so much in a short time within several seconds, the change of the gear ratio in the transmission 3 is dealt with by the change of the rotational speed of the motor 1. Therefore, when the clutch state quantity indicates the state quantity indicating the disengaged state, the control is switched to the synchronous rotation speed control corresponding to the speed ratio after the shift. When the synchronous rotational speed is reached, a synchronous signal is output to the clutch control unit 34. When the clutch state amount indicates a state amount indicating complete engagement, the vehicle travels normally by switching to torque control according to the accelerator pedal opening.

  The clutch control unit 34 gradually reduces the engagement capacity of the clutch 2 based on the shift request, and suppresses the shock associated with the release. Further, the clutch state quantity is output to the carrier frequency variable determination unit 32 and the motor control unit 33. When it is confirmed that the operation of the actuator is completed in the transmission 3 and the shift is completed, and that the motor 1 has reached the synchronous rotation speed, the engagement capacity of the clutch 2 is increased to complete the engagement. In the transmission 3, an actuator is operated in response to a shift request to shift to a desired gear ratio.

  FIG. 3 is a time chart showing the shift control process in the vehicle of the first embodiment. In the initial state, it is assumed that the vehicle is traveling at a predetermined vehicle speed and a gear ratio of 1st. The inverter module temperature is equal to or higher than a predetermined value and the carrier frequency is limited. The case where an upshift request is output from this state to shift to the second speed is shown.

  At time t1, when a shift request is output as the vehicle speed increases, the carrier frequency is increased from the limited carrier frequency, and the motor control unit 33 executes the blow-up prevention torque control so that the motor torque becomes the target motor torque. It is suppressed to become. Here, since torque control is performed with the carrier frequency increased, the target torque can be quickly reduced.

  When the torque of the motor 1 is reduced to the target motor torque at time t2, the clutch 2 is released and the motor control is switched from the blow-up prevention torque control to the synchronous rotational speed control, and the motor rotational speed is reduced to the synchronous rotational speed. At this time, the carrier frequency is increased, the control accuracy is high, and the power is supplied quickly, so that it can be quickly reduced to the synchronous rotation speed.

  When the motor rotation speed decreases to the synchronous rotation speed at time t3, the clutch 2 is re-engaged. When the re-engagement of the clutch 2 is completed at time t4, the carrier frequency is lowered to a frequency corresponding to the inverter modulator temperature, and the motor control is switched from the synchronous rotation speed control to the torque control, and the upshift to the second speed is performed. To complete.

  That is, as in the technique described in Patent Document 1, when the shift timing and the motor control mode switching timing coincide with each other, the shift timing and the motor control are controlled in order to prevent the motor operating state from fluctuating rapidly and causing the controller to malfunction. If the mode switching timing is not matched, shifting may be performed with a low carrier frequency. That is, if a shift is performed in a state where the inverter module temperature is high and the carrier frequency is decreased, the motor torque control accuracy may be decreased, the shift time may be increased, or a shift shock may be caused.

  On the other hand, in the first embodiment, even when the inverter module temperature is high and the carrier frequency is lowered, increasing the carrier frequency during gear shifting improves the motor torque control accuracy and reduces the torque fluctuation. Can be reduced. Thereby, the shock at the time of clutch release or re-engagement can be reduced. Further, since the control accuracy of the motor torque is improved, the rotational speed control can be quickly converged, and the time from the release of the clutch 2 to the re-engagement can be further shortened. Therefore, the idling feeling felt by the driver when the clutch is released can be suppressed. In addition, since the section in which the carrier frequency is increased as in the first embodiment is limited to a short time from the release of the clutch 2 to the re-engagement, the inverter module temperature does not generate excessive heat, and the large size of the inverter 10 And cost increase can be avoided.

As described above, the effects listed below can be obtained in the first embodiment.
(1) The motor 1, the transmission 3 that changes the number of rotations of the motor 1 and outputs it to the drive wheels 5, and the motor 1 and the transmission 3 are interposed. When the shift request of the clutch 2 that is engaged after the shift is completed, the inverter 10 that performs pulse width modulation control at a predetermined carrier frequency, and supplies power to the motor 1, and the shift request of the transmission 3, is output. And a carrier frequency variable determination unit 32 (frequency changing means) that changes the carrier frequency to a carrier frequency lower than the carrier frequency that is being changed. Therefore, during shifting, the number of switching operations in pulse width modulation control can be increased, so that the current control accuracy and thus the control accuracy of the motor can be improved, and the shift time can be shortened while suppressing sudden changes in the motor operating state. Can do. Further, since the motor control accuracy is high, the clutch 2 can be quickly released and re-engaged. In addition, since the carrier frequency is set low again after the fastening, the high frequency state may be short, and the increase in the inverter module temperature can be suppressed, and the increase in size and cost of the inverter 10 can be avoided. it can.

  (2) Temperature sensor 43 (temperature detection means) for detecting the inverter module temperature, and carrier frequency variable determination for limiting the carrier frequency to be lower when the detected inverter module temperature is equal to or higher than a predetermined value than when it is lower than the predetermined value. Unit 32 (frequency limiting unit), and carrier frequency variable determining unit 32 (frequency changing unit) changes the frequency even when the carrier frequency is limited based on the inverter module temperature. . That is, even in a situation where the inverter temperature is high and the carrier frequency is limited, it is a limited time from the release of the clutch 2 to the re-engagement at the time of shifting, and thus the temperature rise of the inverter is suppressed. Therefore, it is possible to suppress an increase in size and cost for improving the heat resistance of the inverter.

  (3) After the gear shift request is output and before the clutch 2 is released, the anti-slip torque control that suppresses the torque of the motor is performed. Therefore, if the carrier frequency is changed high, the torque can be quickly suppressed. A stable speed change can be achieved quickly while avoiding problems such as the motor speed increasing.

  (4) After the clutch 2 is released and before the clutch 2 is engaged, the rotation speed of the motor 1 is maintained at the synchronous rotation speed after the shift, so that the carrier frequency is changed to a high value. It is possible to quickly converge to the target rotational speed, and to achieve a stable shift quickly while avoiding problems such as engagement shock at the time of clutch engagement.

Although the first embodiment has been described above, the present invention is not limited to the electric vehicle according to the first embodiment, and may be applied to other vehicle configurations. For example, as shown in FIG. 4, a generator 7 is driven by an engine 6 that is an internal combustion engine, and battery power or generator power stored thereby is used as it is, and a so-called series hybrid vehicle that runs by driving the motor 1 is used. You may apply.
Further, as shown in FIG. 5, the output of the engine 6 and the output of the motor generator (shown in FIG. 5 is a type including two motor generators 1 and 1a, but may be one motor generator) are represented by planetary gears. However, the present invention may be applied to a so-called parallel hybrid vehicle that outputs and travels through the power combining / distributing mechanism 8. When two motor generators are provided, it is preferable to increase the carrier frequency in the inverters provided in both motor generators, but it is also possible to deal with only one of them.

  In the first embodiment, the always-meshing automatic transmission is used as the transmission. However, the transmission may be applied to an automatic transmission including a planetary gear set. In this case, since the clutch includes a plurality of clutches or brakes for determining the gear position, the clutch to be released and the clutch to be engaged may be different.

DESCRIPTION OF SYMBOLS 1 Motor 2 Clutch 3 Transmission 4 Differential gear 5 Drive wheel 10 Inverter 20 Battery 30 Controller 31 Shift determination part 32 Carrier frequency variable determination part (frequency change means, frequency restriction means)
33 Motor control unit 34 Clutch control unit 43 Temperature sensor

Claims (4)

A motor,
A transmission for changing the number of rotations of the motor and outputting it to the drive wheels;
A clutch interposed between the motor and the transmission, released at the start of shifting of the transmission, and fastened after the end of shifting;
An inverter that performs pulse width modulation control at a predetermined carrier frequency and supplies power to the motor;
Frequency change means for changing to a carrier frequency higher than the carrier frequency before the shift request when the shift request for the transmission is output, and changing to a carrier frequency lower than the carrier frequency during the shift after the end of the shift; ,
A shift control apparatus for a vehicle, comprising: The vehicle shift control device according to claim 1,
Temperature detecting means for detecting the temperature of the inverter;
When the detected inverter temperature is equal to or higher than a predetermined value, frequency limiting means for limiting the carrier frequency lower than when the temperature is lower than the predetermined value;
Have
The vehicle gear change control device according to claim 1, wherein the frequency changing means changes the frequency even when the carrier frequency is limited by the frequency limiting means. The shift control apparatus for a vehicle according to claim 1 or 2,
A vehicular shift control apparatus that performs a blow-up prevention torque control that suppresses the torque of the motor after a shift request is output and before the clutch is released. In the vehicle shift control device according to any one of claims 1 to 3,
A speed change control apparatus for a vehicle, wherein the speed control for maintaining the speed of the motor at a synchronized speed after shifting is performed after the clutch is released and before the clutch is engaged.

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