JP2783929B2 - Drive control device for steering motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a steering motor for operating an electric steering in a battery fork car or the like.

[0002]

2. Description of the Related Art Conventionally, in a device mounted on a vehicle having a plurality of electric steering mechanisms, when a steering motor for operating each electric steering is chopper-controlled, a reference triangular wave voltage and a voltage of a chopper command are controlled. It is known that comparison is performed by a comparison circuit, and each pulse for performing chopper control is output based on the comparison result.
The cycle of the reference triangular wave voltage and the timing of the maximum value and the minimum value are not determined for each steering motor or are often the same.

[0003]

In this case, the cycle of the reference triangular wave voltage and the timing of the maximum value and the minimum value sometimes overlap at the same time, and at this time, the power supply current is superimposed. For example, as shown in FIG. 4, when the voltages of the reference triangular wave are applied at the same timing, the power supply current at that moment becomes extremely large. As a result, the voltage drop of the battery and the voltage drop in the main circuit appear remarkably, the voltage applied to the motor becomes low, and the motor power cannot be sufficiently obtained, and the battery life is shortened due to the concentration of the current of the battery. Or there is a possibility. In particular, when all the circuits of the control system are mounted on one printed circuit board, these problems cannot be ignored.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. When a chopper control is performed on a steering motor that operates an electric steering system, the timing of each voltage of a reference triangular wave is shifted to superimpose a power supply current. An object of the present invention is to provide a steering motor drive control device that is reduced. In particular, it is an object of the present invention to prevent operation problems when all the circuits of the control system are mounted on one circuit board.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an apparatus mounted on a vehicle having a plurality of electric steering mechanisms, a steering motor for operating each electric steering, And a drive circuit for chopper-controlling the steering motor of
This drive circuit has a circuit for outputting a reference triangular wave voltage shifted in phase by a predetermined period, and a comparison circuit for comparing the reference triangular wave voltage with a voltage of a chopper command. Based on a pulse output from the comparison circuit, a steering motor is provided. Is controlled by a chopper.

[0006]

According to the above arrangement, the reference triangular wave voltage shifted in phase by a predetermined period is compared with the voltage of the chopper command.
Each pulse for performing chopper control is output based on the comparison result. As a result, the superimposition of the power supply current is reduced, and it is possible to prevent a decrease in the battery voltage and a voltage drop in the main circuit.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram around a transistor bridge circuit. This transistor bridge circuit 1 includes four MOS field effect transistors (hereinafter referred to as FETs).
2, 3, 4, and 5. One steering motor 7 for operating an electric steering in a battery fork car or the like is connected between the series connection of the FETs 2 and 4 and the series connection of the FETs 3 and 5. FET
The other ends of 2, 3 are connected to the positive electrode of battery 6, and FET
The other ends of 4 and 5 are connected to the negative electrode of battery 6. This transistor bridge circuit 1 drives the steering motor 7 forward or reverse. Although not shown, the transistor bridge circuit 1 is provided with three, for example, three independent steering motors of a battery fork vehicle.

The conduction of the FETs 2 and 3 is controlled by ON / OFF control circuits 8 and 9, respectively. This ON / OF
The F control circuits 8 and 9 use the output voltage of a switching regulator circuit (not shown) as a power supply, have photocouplers 10 and 11 having a light emitting unit and a light receiving unit, and determine whether or not to conduct the FETs 2 and 3 to the input side thereof. The ON / OFF command is input. The conduction of the FETs 4 and 5 is controlled by chopper control circuits 12 and 13, respectively. A chopper pulse is input to an input side of the chopper control circuits 12 and 13 from a comparison circuit described later. ON / OFF above
The command input and the chopper pulse input are linked and controlled by a control circuit (not shown). That is, O
When the N command is input to the ON / OFF control circuit 8,
The chopper pulse is input to the chopper control circuit 13.
When an ON command is input to the ON / OFF control circuit 9, a chopper pulse is input to the chopper control circuit 12.

FIG. 2 is a circuit diagram of a chopper pulse generation circuit for chopper controlling three steering motors. This circuit is mounted on a single printed circuit board, and includes three comparison circuits 21, 31, 41 and a pulse generation circuit (IC401).
5) 24, clock pulse generation circuit (IC555) 2
And 5. The comparison circuit 21 outputs, for example, a chopper pulse for chopper-controlling the steering motor 7, and the comparison circuits 31, 41 output chopper pulses for chopper-controlling the remaining two steering motors (not shown).

Each of the comparison circuits 21, 31, 41
A chopper command is input to the input terminal, and reference triangular waves output from the pulse generation circuit 24 and out of phase with each other are input to the negative input terminal. Each comparison circuit 2
At 1, 31, 41, the reference triangular wave voltage is compared with the voltage of the chopper command, and then a chopper pulse is output.
These chopper pulse outputs are input to one of the chopper control circuits 12 and 13 of the corresponding transistor bridge circuit by a control circuit (not shown). Further, a clock pulse from the clock pulse generation circuit 25 is input to a clock terminal of the pulse generation circuit 24. Note that the pulse generation circuit 24 and the clock pulse generation circuit 25
Power is supplied from the power supply 6.

Next, the circuit operation of the above configuration will be described with reference to FIG. FIG. 3 shows a voltage waveform of a pulse input to and output from each terminal of the comparison circuits 21, 31, and 41 and a current waveform of a power supply. A clock pulse is output from the clock pulse generation circuit 25, and the clock pulse is input to a clock terminal of the pulse generation circuit 24. In synchronism with this clock pulse, pulses shifted by a quarter period from the output terminal of the pulse generation circuit 24 are output, and these are integrated, and as shown in FIG. A reference triangular wave shifted by one period is generated. Each of the reference triangular waves is compared with a comparison
1, 41 are input to the-input terminals.

Chopper commands are input to the + input terminals of the comparison circuits 21, 31, and 41, respectively. The comparison circuits 21, 31, 41 compare the input reference triangular wave voltage with the voltage of the chopper command, and when the voltage of the chopper command is higher than the reference triangular wave voltage as shown in FIG.
Outputs a chopper pulse.

In FIG. 1, when an ON command is input to an ON / OFF control circuit 8 and the FET 2 is turned on, the chopper pulse is input to the chopper control circuit 13 and the FET 5 is turned on. As a result, a current flows from the battery 6 to the circuit of the FET 2, the steering motor 7, and the FET 5. Conversely, when the ON command is input to the ON / OFF control circuit 9 and the FET 3 is turned on, the chopper pulse is input to the chopper control circuit 12 and
ET4 is conducted. As a result, F
A current flows through the circuit of ET3, steering motor 7, and FET4.

As described above, from the output terminal of the pulse generating circuit 24, pulses shifted from each other by a quarter period are output, and the reference triangular waves formed by integrating the pulses are compared with the comparison circuits 21, 31, 41. After the reference triangular wave voltage is compared with the voltage of the chopper command, each chopper pulse for chopper-controlling the steering motor is output. Therefore, many of these chopper pulses are not superimposed at one time. Accordingly, the current waveform of the power supply becomes as shown in FIG. 3, and the peak value becomes smaller than the current waveform of the conventional power supply shown in FIG. In particular, all circuits of the control system are 1
When mounted on a single printed circuit board, the effect is significant.

In the above embodiment, the timing of each voltage of the reference triangular wave to be compared with the voltage of the chopper command is shifted by a quarter period. However, the shifting period is only a quarter. The present invention is not limited to this, and may be set so that each chopper pulse for chopper-controlling the steering motor is less superimposed. In this embodiment, the case where the number of the transistor bridge circuits is three has been described.
Applicable to more than two cases.

[0016]

As described above, according to the present invention, the timing of each voltage of the reference triangular wave is shifted, so that the chopper pulse for controlling the chopper of each steering motor is:
Many are not superimposed at one time, and superimposition of the current of the power supply is reduced. As a result, a voltage drop of the battery and a voltage drop in the main circuit can be prevented, and a shortage of the power of the steering motor and a shortening of the battery life due to a current concentration of the power supply can be prevented. In particular, when all the circuits of the control system are mounted on one printed circuit board, the effect of preventing the voltage drop in the main circuit is great.

[Brief description of the drawings]

FIG. 1 is a circuit diagram around a transistor bridge circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a chopper pulse generation circuit for performing chopper control of a steering motor.

FIG. 3 is a diagram showing voltage waveforms input / output to a comparison circuit and current waveforms of a power supply.

FIG. 4 is a diagram showing voltage waveforms input to and output from a conventional comparison circuit and current waveforms of a power supply.

[Explanation of symbols]

1 Transistor bridge circuit 2,3,4,5 MOS type field effect transistor (FE
T) 6 Battery 7 Steering motor 12, 13 Chopper control circuit 21, 31, 41 Comparison circuit 24 Pulse generation circuit

────────────────────────────────────────────────── (5) References JP-A-58-185154 (JP, A) JP-A-62-23390 (JP, A) JP-A-3-91094 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) H02P 7/29

Claims (1)

(57) [Claims] An apparatus mounted on a vehicle having a plurality of electric steering mechanisms, comprising: a steering motor for operating each electric steering; and a drive circuit for chopper-controlling these steering motors. The circuit has a circuit that outputs a reference triangular wave voltage shifted in phase by a predetermined period, and a comparison circuit that compares the reference triangular wave voltage with the voltage of the chopper command. Based on the pulse output from the comparison circuit, the steering motor is choppered. A drive control device for a steering motor, wherein the drive control device is controlled.