JP2017184573A - Device for controlling vehicle travelling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling a vehicle travelling motor that can change over to a mode of properly increasing a regenerative current even in a situation where a vehicle loaded condition varies.SOLUTION: A controller 37 is configured to be capable of changing over to a regenerative boost braking mode that increases a target armature current at a regenerative braking mode, from the regenerative braking mode. The controller 37 changes over to the regenerative boost braking mode from the regenerative braking mode based on an amount of variation of duty of armature energizing switching elements Q5, Q6.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device for a vehicular travel motor.

  A technique for regenerative braking using a DC shunt motor as a traveling motor in a vehicle such as a battery forklift is known (for example, Patent Document 1).

Japanese Patent No. 3626893

  By the way, in a vehicle without a rotation sensor in the travel motor, when the regenerative current is increased and the braking torque is increased in the regenerative braking mode at the time of switchback accompanying the occupant (operator) operation (the target armature current in the regenerative braking mode) If the braking torque is adjusted so that the deceleration on the flat road is appropriate, the braking torque is insufficient on the slope and the braking distance is extended. That is, when the vehicle body is regeneratively braked, the regenerative force required differs depending on the load state, so it is necessary to determine the flat road and the slope and adjust the regenerative force.

  An object of the present invention is to provide a control device for a vehicular travel motor that can be switched to a mode in which a regenerative current is appropriately increased even in a situation where load conditions on the vehicle are different.

  According to the first aspect of the present invention, a DC shunt motor is used as the traveling motor, the armature energization switching element is configured as a circuit for energizing the armature of the DC shunt motor, and the field of the DC shunt motor is set. A vehicle travel motor control device having a bridge configuration of a field coil energization switching element as a circuit for energizing a coil, comprising a control unit for duty control of the armature energization switching element and the field coil energization switching element The control unit is configured to be switchable from a regenerative braking mode to a regenerative boost braking mode that increases a target armature current in the regenerative braking mode, and the control unit is based on a change in duty of the armature energization switching element. Regenerative braking mode And summarized in that a switching means for switching the regenerative boost braking mode.

  According to the first aspect of the present invention, the switching means switches from the regenerative braking mode to the regenerative boost braking mode based on the amount of change in the duty of the armature energization switching element. As described above, the change amount of the duty of the armature energization switching element is regarded as a detection element of the switching timing, so that it is possible to switch to the mode in which the regenerative current is appropriately increased even in a situation where the load state on the vehicle is different.

  According to a second aspect of the present invention, in the vehicular travel motor control device according to the first aspect, the switching unit is configured to generate a regenerative braking mode when a duty change amount of the armature energization switching element is larger than a threshold value. To the regenerative boost braking mode.

  According to a third aspect of the present invention, the vehicle travel motor control device according to the first or second aspect may be mounted on a forklift.

  ADVANTAGE OF THE INVENTION According to this invention, it can switch to the mode which enlarges a regeneration electric current appropriately also in the condition where the load condition to a vehicle differs.

The schematic side view of a forklift. The circuit diagram of the control apparatus of the forklift travel motor. The flowchart for demonstrating an effect | action. (A), (b) is a time chart for demonstrating an effect | action. (A), (b) is a time chart. (A), (b) is a time chart.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the forklift 10 is a battery forklift, and is a forklift that performs conveyance and cargo handling work with an electric motor. Drive wheels (front wheels) 12 a are provided at the front lower part of the vehicle body 11 of the forklift 10, and steering wheels (rear wheels) 12 b are provided at the rear lower part of the vehicle body 11. A cargo handling device 13 is provided at the front of the vehicle body 11.

  A mast 14 constituting the cargo handling device 13 is erected on the front portion of the vehicle body 11. The mast 14 includes a pair of left and right outer masts 14a supported so as to be tiltable back and forth with respect to the vehicle body 11, and an inner mast 14b that slides up and down. A lift cylinder 15 is disposed at the rear of each outer mast 14a. A lift bracket 17 having a fork 16 is supported inside the inner mast 14b so as to be movable up and down. Then, the fork 16 is lifted and lowered together with the lift bracket 17 by the expansion and contraction of the lift cylinder 15.

  The pair of left and right tilt cylinders 18 is pivotally connected to the vehicle body (body frame) 11 at the base end side, and is rotatably connected to the side surface of the outer mast 14a. The mast 14 tilts back and forth as the tilt cylinder 18 is driven to expand and contract.

  The driver's cab 19 is provided with a driving seat 20 on which a driver can sit. A steering wheel column 21 is provided in front of the driving seat 20, and a steering wheel 22 for changing the steering angle of the steering wheel 12b is mounted on the steering wheel column 21. A lift lever 23 and a tilt lever 24 are provided on the front side of the cab 19. The lift lever 23 is a lever for moving the fork 16 up and down, and the tilt lever 24 is a lever for tilting the mast 14 in the front-rear direction. An accelerator pedal 25 is provided on the floor of the driver's seat, and the vehicle speed is set according to the amount of operation of the accelerator pedal 25 (accelerator opening).

  In addition, a direction lever (forward / reverse lever) 26 is provided on a side surface of the handle column 21, and the direction lever 26 is for instructing a traveling direction (traveling direction) of the vehicle.

  A battery 27, a travel motor (travel electric motor) 28, and a cargo handling motor (load handling electric motor) 29 are mounted on the vehicle body 11. A DC shunt motor is used as the traveling motor 28. The travel motor 28 is driven by the battery 27, and the drive wheel 12a is driven. Specifically, the output shaft of the travel motor 28 is connected to the rotation shaft of the drive wheel 12a via a speed reducer. When the output shaft is rotated by the drive of the travel motor 28, the rotation shaft of the drive wheel 12a is rotated along with the rotation. The drive wheel 12a is driven by rotation.

  In addition, a cargo handling motor 29 is driven by the battery 27, and a hydraulic pump (not shown) is driven by driving the cargo handling motor 29. Based on the driving of the hydraulic pump, the lift cylinder 15 and the tilt cylinder 18 are expanded and contracted so that the fork 16 can be moved up and down and tilted.

  As shown in FIG. 2, the control device 30 for the travel motor 28 is mounted on the forklift 10. A traveling motor 28 which is a direct current dividing motor has an armature (armature) 32 and a field coil (field coil) 33. The armature 32 is provided on the rotor, and the field coil 33 is provided on the stator.

  The control device 30 has a bridge circuit 31. The bridge circuit 31 has six switching elements Q1 to Q6. The armature energization switching elements Q5 and Q6 are configured as a bridge as a circuit for energizing the armature 32 of the travel motor (DC shunt motor). A field coil energizing switching element Q1, Q2, Q3, Q4 is used as a circuit for energizing the field coil 33 of the travel motor (DC shunt motor).

  Specifically, the positive electrode bus Lp is connected to the positive electrode of the battery 27 as a DC power source, and the negative electrode bus Ln is connected to the negative electrode of the battery 27. Switching elements Q1, Q2 are connected in series between positive electrode bus Lp and negative electrode bus Ln. Switching elements Q3 and Q4 are connected in series between positive electrode bus Lp and negative electrode bus Ln. A field coil 33 (stator coil) is connected between a midpoint between the switching elements Q1 and Q2 and a midpoint between the switching elements Q3 and Q4.

  Switching elements Q5 and Q6 are connected in series between positive electrode bus Lp and negative electrode bus Ln. An armature 32 (rotor coil) is connected between the midpoint between the switching elements Q5 and Q6 and the negative electrode bus Ln (ground). That is, the armature 32 is connected in parallel to the switching element Q6.

  Power MOSFETs are used for the switching elements Q1 to Q6. An IGBT (insulated gate bipolar transistor) may be used as the switching element. Feedback diodes D1 to D6 are connected in reverse parallel to the switching elements Q1 to Q6, respectively.

  A current sensor 34 is provided in series with the armature 32, and a current (armature current) Ia flowing through the armature 32 is detected by the current sensor 34. A current sensor 35 is provided in series with the field coil 33, and the current (field current) If flowing through the field coil 33 is detected by the current sensor 35.

A main circuit contactor 36 is provided on the battery 27 side of the positive electrode bus Lp.
The control device 30 includes a controller 37. The controller 37 includes a microcomputer, a memory, and the like, and the memory stores various control programs necessary for driving the traveling motor 28 and various data and maps necessary for the execution. The control program includes a control program for rotating the traveling motor 28 and the like, and can execute regenerative braking or regenerative boost braking (control for increasing the target armature current in regenerative braking).

  In FIG. 2, the controller 37 is connected to the gates of the switching elements Q1 to Q6. The controller 37 as a control unit performs duty control on the armature energization switching elements Q5 and Q6 and the field coil energization switching elements Q1, Q2, Q3 and Q4.

  Current sensors 34 and 35 are connected to the controller 37. And the controller 37 outputs the control signal which controls the traveling motor 28 so that it may become a target output to each switching element Q1-Q6 based on the detection signal of each sensor 34,35.

  The controller 37 inputs an operation signal output from the operation sensor in accordance with an operation by an occupant (operator) and controls the vehicle operation. More specifically, a direction switch 38 and an accelerator sensor 39 are electrically connected to the controller 37. The direction switch 38 is disposed in the handle column 21 and detects the operation position (forward position or reverse position) of the direction lever 26. The direction switch 38 outputs a detection signal corresponding to the operation position of the direction lever 26 to the controller 37. Then, the controller 37 detects that the operation position of the direction lever 26 is the forward movement position or the reverse movement position by inputting a detection signal from the direction switch 38.

  The accelerator sensor 39 detects the operation amount of the accelerator pedal 25. The controller 37 detects the presence / absence of the operation of the accelerator pedal 25 and the operation amount (accelerator opening) by inputting a signal from the accelerator sensor 39. Torque is determined according to the accelerator opening, and the regenerative torque is determined according to the accelerator opening by controlling the regenerative current of the armature 32. That is, when the accelerator pedal 25 is depressed, a large amount of armature current flows, and the duty is determined to control this current.

The controller 37 detects various operations and controls the traveling motor 28 to adjust the vehicle speed so that the rotational speed of the traveling motor 28 corresponds to the operation amount of the accelerator pedal 25.
The controller 37 detects a current (armature current) Ia flowing through the armature 32 and a current (field current) If flowing through the field coil 33 by signals from the current sensors 34 and 35. The controller 37 is configured to be able to switch from the regenerative braking mode to a regenerative boost braking mode that increases the target armature current in the regenerative braking mode. In the forklift 10, the traveling motor 28 is not provided with a rotation sensor.

Next, the operation of the control device 30 for the travel motor 28 of the forklift 10 will be described.
The controller 37 sets a regenerative braking mode when the direction lever 26 is switched back (operated from forward to reverse, or operated from reverse to forward) and the accelerator pedal 25 is depressed, and is regenerated as necessary. Transition from the braking mode to the regenerative boost braking mode. In the following description, it is assumed that the vehicle is switched from forward to reverse. The controller 37 executes the process shown in FIG. 3 to switch from the regenerative braking mode to the regenerative boost braking mode.

  As shown in FIG. 3, the controller 37 determines in step S <b> 100 whether or not the traveling direction (traveling direction) of the vehicle has changed due to the operation of the direction lever 26. When the traveling direction (traveling direction) of the vehicle changes, the controller 37 proceeds to step S101 and sets the regenerative braking mode. In the regenerative braking mode, the controller 37 controls the duty of the switching elements Q1, Q4, and Q5 in FIG. 2, for example, and energizes the field coil 33 and the armature 32 through a current path indicated by a broken line in FIG.

  That is, the back coil electromotive force generated in the armature 32 energizes the field coil 33 through the path of the armature 32 → switching element Q5 → switching element Q1 → field coil 33 → switching element Q4 → armature 32. Further, a current due to the counter electromotive force generated in the armature 32 is passed through the path of the armature 32 → the switching element Q5 → the battery 27 → the armature 32, and the counter electromotive force generated in the armature 32 is returned to the battery 27.

  In step S102 in FIG. 3, the controller 37 determines the duty of the armature energization switching element Q5 (Q6), that is, the armature duty so that the actual armature current Ia becomes the target armature current Ia according to the accelerator opening. To do. In step S103, the controller 37 switches from the regenerative braking mode to the regenerative boost braking mode based on the change amount of the armature duty.

  Specifically, in step S103, the controller 37 determines whether the duty change amount is greater than a threshold value. More specifically, it is determined whether or not the absolute value of the value obtained by subtracting the previous duty (n−1) from the current duty (n) is greater than a predetermined threshold value X. Then, when the change amount of the duty is smaller than the threshold value, the controller 37 continues the regenerative braking mode in step S106. On the other hand, if the change amount of the duty is larger than the threshold value in step S103, the controller 37 proceeds to step S104. The controller 37 sets the regenerative boost braking mode in step S104, and controls the actual armature current to be a value obtained by adding the predetermined value α to the target armature current in step S105. That is, the target armature current in the regenerative braking mode is increased.

  If the amount of change in the armature duty (duty of the armature energization switching elements Q5, Q6) is zero, if the torque is maximum at a duty of 100%, the moment when regenerative braking is entered with the switchback operation, Since the duty is output 100% for a certain time, the duty does not change. In this case, the regenerative braking mode is not switched to the regenerative boost braking mode.

  Thus, since the induced voltage generated by the motor is proportional to the rotation speed, if the change amount of the armature duty is larger than the threshold value, it is determined that the vehicle is not decelerating and is switched to the regenerative boost braking mode (transition).

The behavior of the armature current Ia and the field current If during general deceleration will be described with reference to FIGS.
FIGS. 5A and 6A show the current (field current) If flowing through the field coil 33, the current (armature current) Ia flowing through the armature 32, and the armature duty. 5B and 6B show changes in the armature duty. 5A and 5B show the behavior when traveling on a flat road, and FIGS. 6A and 6B show the behavior when traveling on a slope.

  5A and 6A, the horizontal axis represents time, the vertical axis represents the current (field current) If flowing through the field coil 33, the current flowing through the armature 32 (armature current) Ia, and the armature duty. Yes. The controller 37 sets an armature duty corresponding to the accelerator opening so as to flow an armature current Ia corresponding to the accelerator opening. In FIGS. 5B and 6B, the horizontal axis represents time, and the vertical axis represents the amount of change in armature duty. 5 and 6 and later-described FIG. 4, the field current If has a value corresponding to the accelerator fully open.

5 and 6, the armature current Ia changes from positive to negative at timing t1, and the regenerative braking mode is started.
As shown in FIGS. 5 (a) and 5 (b), in regenerative braking when running on a flat road, the armature duty is lowered to maintain the target current after the timing t1 of the start of regenerative braking after the switchback operation. At this time, the armature duty decreases toward zero when the machine base decelerates, and the armature duty becomes zero as the machine base stops. At this time, as the armature duty decreases, the change amount of the armature duty is smaller than the threshold value, which shows a behavior peculiar to a flat road.

  On the other hand, as shown in FIGS. 6 (a) and 6 (b), in regenerative braking when running on a slope, the armature duty is lowered to maintain the target current after the timing t1 of the start of regenerative braking after the switchback operation. At this time, when the armature duty decreases toward zero when the machine base decelerates, the armature duty does not decrease. This is because the rotational speed does not decrease to obtain the target current, and therefore it is not necessary to decrease the duty, and the regenerative braking force is smaller than the current forklift load state and the braking force is small, so the duty does not decrease easily. If the regenerative braking mode is not exited indefinitely, the braking distance becomes long, the change amount of the armature duty is larger than the threshold value, and the behavior peculiar to the slope is shown.

  On the other hand, in this embodiment, as shown in FIGS. 4A and 4B, in regenerative braking when running on a slope, when the armature duty decreases toward zero when the machine base decelerates, switching for energizing the armature is performed. When the amount of change in the duty of the elements Q5 and Q6 is larger than the threshold value, the regenerative braking mode is switched to the regenerative boost braking mode. In other words, on a slope, the armature duty decreases as the machine base decelerates, but the braking force and the external force do not decrease in balance, so it is determined that the armature duty is not decelerating if the change amount of the armature duty is greater than the threshold value. Switch to regenerative boost braking mode. That is, the controller 37 monitors the change in the armature duty to start the process of exiting from the regenerative braking mode, and the regenerative power is increased by regenerative boost braking.

  4, 5, and 6 are obtained by actual measurement by the present inventors, and may vary depending on the weight of the vehicle and the presence or absence of a load. 4A and 4B, the process of step S103 of FIG. 3 is not executed in the initial period T1 of regenerative braking.

According to the above embodiment, the following effects can be obtained.
(1) The controller 37 as a control unit is configured to be switchable from the regenerative braking mode to a regenerative boost braking mode that increases the target armature current in the regenerative braking mode. The controller 37 includes switching elements Q5 and Q6 for energizing the armature. There is switching means (switching function) for switching from the regenerative braking mode to the regenerative boost braking mode based on the amount of change in duty. Therefore, by capturing the amount of change in the duty of the switching element for energizing the armature as a detection element for the switching timing, it is possible to switch to a mode in which the regenerative current is appropriately increased even in a situation where the load state on the vehicle is different, such as a deceleration state on a slope. . Specifically, it is possible to appropriately switch from the regenerative braking mode to the regenerative boost braking mode even on a slope.

  (2) The switching means (switching function) switches from the regenerative braking mode to the regenerative boost braking mode when the amount of change in duty of the armature energization switching elements Q5 and Q6 is larger than the threshold value. Therefore, it is possible to appropriately switch from the regenerative braking mode to the regenerative boost braking mode even on a slope.

(3) Since it is mounted on a forklift, it is practical.
The embodiment is not limited to the above, and may be embodied as follows, for example.
-Although applied to a forklift, it is not limited to this. For example, an industrial vehicle other than a forklift may be used, or a vehicle other than an industrial vehicle may be used.

  DESCRIPTION OF SYMBOLS 10 ... Forklift, 28 ... Traveling motor, 30 ... Control apparatus, 34 ... Current sensor, 37 ... Controller, Q1, Q2, Q3, Q4 ... Field coil energization switching element, Q5, Q6 ... Armature energization switching element.

Claims (3)

A DC shunt motor is used as a travel motor, and a bridge configuration of an armature energizing switching element is provided as a circuit for energizing the armature of the DC shunt motor, and field coil energization is provided as a circuit for energizing a field coil of the DC shunt motor. A vehicle travel motor control device having a bridge configuration of a switching element for a vehicle,
A control unit for duty-controlling the armature energization switching element and the field coil energization switching element;
The control unit is configured to be switchable from a regenerative braking mode to a regenerative boost braking mode that increases a target armature current in the regenerative braking mode,
The control unit for a vehicular travel motor, wherein the control unit includes switching means for switching from a regenerative braking mode to the regenerative boost braking mode based on a change in duty of the armature energization switching element.   2. The vehicle travel motor according to claim 1, wherein the switching unit switches from the regenerative braking mode to the regenerative boost braking mode when the amount of change in duty of the armature energization switching element is larger than a threshold value. Control device.   The vehicle travel motor control device according to claim 1, wherein the vehicle travel motor control device is mounted on a forklift.

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