JPS63114509A - Control system of electric motor car - Google Patents

Abstract

PURPOSE:To increase the driving force of a motor temporarily by mounting an emergency switch augmenting currents fed to the motor exceeding a rated value. CONSTITUTION:A comparator IC1 compares acceleration voltage Vacc and a saw tooth signal, and feeds a switching signal Va consisting of a pulse waveform, in which pulse width interrupting for a fixed period changes, to a transistor TR. When voltage generated in a shunt resistor R1 is lower than reference voltage VR, an output from the comparator IC1 reaches a low level, and the transistor TR is turned OFF. When an emergency switch S is turned On, the other hand, the transistor TR is short-circuited through a resistor R2, and currents flows regardless of a current limiting value. Accordingly, overcurrents can be caused to flow through a motor M.

Description

[Detailed Description of the Invention] [Summary] In a control device for an electric vehicle that supplies current to a motor via a semiconductor element, the current supplied to the motor is temporarily increased beyond the rated value by operating an emergency switch. When large torque is required, such as when going over a step,
This allows the required torque to be generated.

[Industrial application field]

The present invention relates to a braking system for electric vehicles, and in particular, when a large torque is required at times, such as when a vehicle goes over a bump, a large current is instantaneously passed through the drive motor to generate a torque exceeding the rated value. This invention relates to a control system for electric vehicles that enables

[Conventional technology]

Semiconductor elements such as transistors are usually used in the power circuits that supply current to the motors in electric vehicles, but the current value flowing through such half-quad elements must exceed the absolute maximum rating of the semiconductor element. Naturally, this should not be the case, and for this reason, a current limiting circuit is usually provided to limit the current value. In general, the limiting current value in such a current limiting circuit should be at most 90% or less of the maximum rated collector current value of the semiconductor element, and even if there is a slight adjustment error, it should not exceed 100% of the maximum rated value. has been done. For this reason, a current exceeding this set value does not flow through the semiconductor element, thus preventing the element from being destroyed.

[Problem that the invention seeks to solve]

However, when driving an electric vehicle, for example when going over a step, it would be possible to get over the step if a slightly larger current could be applied, even if only momentarily, but the current limiting circuit operates. Sometimes you can't get over it.

Therefore, in order to provide the necessary ability to overcome the steps,
There is a problem in that a semiconductor element with a large maximum rating value must be selected, which inevitably makes the element expensive.

[Means for solving problems]

The present invention is an attempt to solve the problems of the prior art, and is aimed at an electric vehicle that drives a semiconductor element through a current limiting means and supplies current from a power source to a motor via this semiconductor element. An emergency switch shall be provided in the control device.

An emergency switch is one that can increase the current supplied to the motor beyond its rated value.

[For production]

In the method of the present invention, the current supplied to the motor can be increased beyond the rated value by operating the emergency switch, so the driving force of the motor can be temporarily increased. You will be able to get over even obstacles that are impossible to get over.

[Embodiments of the invention]

FIG. 1 shows the configuration of an embodiment of the present invention.

In the figure, 1 is a throttle polyurethane, 2 is a sawtooth wave generator, ICI and IC2 are comparators, TR is a drive current control transistor, M is a motor, Sl is an emergency switch, and R1 and R2 are resistors, respectively.

In FIG. 1, a throttle polyurethane 1 is coupled to a throttle (not shown), and based on the operation of the throttle, an accelerator voltage V sc indicating the amount of throttle operation is generated.
generate c. The comparator C1 has its output side pulled up to a constant voltage Vcc, and compares the accelerator voltage Vscc with the sawtooth wave signal of the sawtooth wave generator 2, so that the voltage Vmcc is the sawtooth wave voltage. It has the function of generating an output that becomes high level when the As a result, - a switching signal V consisting of a pulse waveform (chopping waveform) whose pulse width changes intermittently
a, but the switching signal Va is the signal Va
When ce exceeds the peak value of the sawtooth wave, it becomes a high level continuous signal, and when the signal V sec falls below the bottom value of the sawtooth wave, it becomes a low level continuous signal. The transistor TR is in a conductive state when the switching signal Va is a continuous high-level signal, and is in a cut-off state when the switching signal Va is a continuous low-level signal.
When is a pulse waveform, it is intermittently conductive, and current flows from the power supply Vc to the motor M via the shunt resistor R1. Therefore, when the signal Va is a high-level continuous signal, the motor rotates at full power, and when the signal Va is an intermittent pulse, the motor generates a driving force according to the pulse width.

Further, when the signal Va is a continuous low level signal, the motor is in a stopped state. Incidentally, such a drive signal generation method in open loop control is conventionally known and is also described in Japanese Patent Laid-Open No. 60-91803 by the present applicant.

The voltage developed across the shunt resistor R1 by applying a voltage to the motor M is compared with the reference voltage VR in the comparator IC2. The comparator C2 is an oven collector type, and when the voltage of the shunt resistor R1 is lower than the reference voltage VR, the output of the comparator ICI is set to a low level, thereby cutting off the signal Va and turning off the transistor TR. A current limiting action is performed to limit the current of M.

The emergency switch S1 is for passing an overcurrent to the motor M, and by turning it on, the transistor TR is short-circuited via the resistor R2, and current flows regardless of the current limit value. Therefore, by selecting the value of the resistor R2, an overcurrent can be applied to the motor M. When the switch S1 is turned off, current flows through the transistor TR again, returning to the normal control state.

FIG. 2 shows the configuration of another embodiment of the present invention. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals. 3 is an exclusive OR circuit, 4.5 is an integration circuit, 6 is a current setting volume, TR5 to TR8 are drive current control transistors, TR5 to TR8 are current control signal generation transistors, INVl, INV2. INV3 and INV4
is an inverter, S2 is a forward/reverse selector switch, S3 is an emergency switch 3, and R4 is a resistor.

3 is a diagram showing signals of each part in the control signal generation part for the drive current control transistor in the embodiment of FIG. 2, and FIG. 4 is a diagram showing the signals of each part in the control signal generation part for the current limiting circuit. The respective signals are indicated by the same reference numerals at corresponding positions in FIG.

In FIG. 2, the drive signal generation method using the throttle volume 1, sawtooth wave generator 2, and comparator ICI is the same as in the embodiment shown in FIG. A switching signal Va as shown in the figure is generated.

The exclusive OR circuit 3 is supplied with a signal to one input via the changeover switch s2, which becomes a low level when the vehicle is moving forward and a signal that becomes high level when the vehicle is moving backward. Now considering the forward case, the switching signal Va is applied to the inverter INVI via the exclusive OR circuit 3 without changing its polarity, and is inverted there to obtain the signal vb. Since the resistances of the integrating circuits 4 and 5 are short-circuited by diodes, charging is fast but discharging is slow. Therefore, the signal vb generates the signal Vc through the integrating circuit 4, and the inverter INV2 is connected to the integrating circuit 4.
When the output is below a certain level, a signal Ve is output. Furthermore, the inverter INV3 inverts the signal vb and outputs a signal Vb.
f, thereby generating a signal Vg via an integrating circuit 6, and further generating a signal vh via an inverter INV4 when the signal Vg is below a certain level. As shown in FIG. 3, the signal Ve has a certain pause time tr from the rising edge of the signal Va, and the signal vh has a certain pause time tr from the rising edge and falling edge of the signal Va.

Signals Ve and Vh are applied to drive current control transistors TR1 and TR2, respectively. On the other hand transistor TR4
is in a conducting state with a positive voltage applied to its base. Therefore, in the motor M, when the switching signal Va is at a "high level", the transistors TR1 and TR4 are turned on and are energized by the power supply Vc to generate rotational force, and when the signal Va is at a "low level", the transistors TR2 and TR4 are turned on. is “on”
, and enters the dynamic braking state, so the switching signal V
It generates a driving force that changes depending on the state of a, or enters a braking state.

When the vehicle is moving backward, the polarity of the switching signal Va is reversed through the exclusive OR circuit 3, and a positive voltage is applied to the base through the selector switch S2, thereby rendering the transistor TR3 conductive. Therefore, in the motor M, when the switching signal Va is at a high level, transistors TR2 and TR3 are turned on and energized by the power supply Vc to generate rotational force in the opposite direction, and when the switching signal Va is at a low level, transistors TRII and TR3 are turned on. Since the switching signal V
It generates a backward driving force that changes depending on the state of a, or enters a braking state.

The comparator IC2 normally compares the terminal voltage of the shunt resistor R1 with the voltage Vs set from the power supply oc via the resistor R2 and the current setting volume 6, and determines whether the terminal voltage of the shunt resistor R1 exceeds the set voltage Vs. By lowering the drive signals Ve and Vh to a low level, the current flowing through the transistors TR1 and TR2 is cut off, thereby preventing the drive transistors TRI to TR4 from being destroyed due to overcurrent.

The emergency switch S3 is for passing an overcurrent to the motor M, and by turning it on, the power supply V cc
The capacitor CI is charged from the transistor TR5.
immediately turns on, and its collector voltage ■1 becomes low level. As a result, the transistor TR6 is also turned on, and a voltage v2 is applied to the capacitor C2 from the power supply (c-) through the resistor R3, and a charging current flows through the capacitor C2, producing an output signal Vd having a differential waveform. The transistor TR7 is turned on when the signal Vd is greater than a certain value Vt, and at the same time, the transistor TR8 is also turned on, shorting the resistor R2. As a result, the output signal voltage Vs of the current setting volume 6 rises, so the current limit values of the driving transistors TRI and TR2 become larger, a current larger than the normal current flows through the motor M, and the motor M reaches its rated value. Generates more rotational force.

The duration of the overcurrent in this case is a predetermined short time 1. determined by the time when the signal Vd exceeds a certain level Vt. can be arbitrarily determined depending on the time constant of the circuit including the capacitor C2.

Moreover, the signal VI is the signal ■. It does not become low level unless Vr becomes less than a predetermined value Vr. Therefore, by increasing the discharge time t2 of the capacitor C1, at least the time t
During the period 2, the signal 2 will not rise again. Therefore, current cannot flow through the driving transistors TRI and TR2 unless there is an interval of at least time t2 or more.

In this way, overcurrent can be caused to flow through the driving transistor only at intervals of a predetermined time or longer at predetermined short intervals, and an excessive load is not placed on the transistor.

Normally, the absolute maximum rating value of a semiconductor element is determined by the relationship where the peak current rating value is (X+Y)(A), where the continuous rating value of the collector current is defined as X (A). That is, the peak rating value in a short time is larger than the continuous maximum rating value X (A) by a certain margin value Y (A).

At present, power transistors whose peak current rated value is more than twice the continuous rated value are available, and therefore, the method of this embodiment can effectively increase the driving force of the motor in an emergency.

Note that the method of the embodiment shown in FIG. 2 is less effective unless the emergency switch S3 is operated with the throttle fully open. Therefore, as shown in Figure 5, an emergency switch S3 consisting of a button switch is provided near the throttle grip (or lever) shown at 7 so that it can be operated at the same time as the throttle grip, or the throttle grip can be operated when the throttle is fully opened. It is more effective to adopt a method in which the emergency switch S3 is turned on by turning the emergency switch S3 even more strongly.

〔Effect of the invention〕

Since the present invention is configured and functions as described above, it is possible to cause a current higher than the rated value to flow for a short time to the motor that drives the electric vehicle, thereby generating a larger driving force. Since the short-time capacity of the motor is quite large, this can be used effectively. In addition, if a current limiting circuit is installed and the motor is driven by a transistor or the like, it is possible to draw out the full potential of the power element, and overcurrent is passed for a short time and at intervals of a certain period of time, so the element is There will be no negative impact.

[Brief explanation of the drawing]

1 and 2 are diagrams each showing an embodiment of the present invention, FIG. 3 is a diagram showing various signals in the control signal generation portion for the drive current control transistor in the embodiment of FIG. 2, and FIG. 2 is a diagram showing various signals in the control signal generation section for the current limiting circuit in the embodiment of FIG. 2, and FIG. 5 is a diagram showing an example in which an emergency switch is provided on the throttle grip. 1...Throttle volume, 3...Exclusive OR circuit, 4.5...Integrator circuit, 6...
...Current setting volume, 7...Throttle grip, TR, TR1-TR4...Transistor for drive current control, TR5-TR8...Transistor for generating current control signal , icl, IC2...
... A comparator forming the main part of the current limiting means, 31.
S3...Emergency switch, S2...Forward/reverse selector switch, M...Motor. Patent applicant: Suzuki Motor Co., Ltd., 7'
7';>, - Fig. 2 (It! I) 9 gear 1 Hi H floor 111 Ji sui-cho = δ) Fig. 3 t4 tr Fig. 4 Fig. 5 Association/Switch IT pull) Mr. 4 track f! Take-off 1 (Bokuki, Switch) Voluntary amendment to the procedure) January 21, 1985 1, Indication of the case 1985 Patent Application No. 26208
No. 4 No. 2, Title of the invention Control method for electric vehicles 3, Relationship with the case of the person making the amendment Patent applicant

Claims (3)

[Claims] (1) In a control device for an electric vehicle that drives a semiconductor element through a current limiting means and supplies current from a power source to a motor via the semiconductor element, the current supplied to the motor exceeds a rated value. 1. A control method for an electric vehicle, characterized in that an emergency switch is provided, and the driving force of a motor can be temporarily increased by operating the emergency switch. (2) A control system for an electric vehicle according to claim 1, wherein the means for increasing the motor supply current bypasses the semiconductor element. (3) A control method for an electric vehicle according to claim 1, wherein the means for increasing the motor supply current temporarily increases the limit value of the current limiting means.