JP2801004B2 - Control circuit of valve drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a control circuit for a valve drive device, and more particularly to a control circuit for operating a valve with an electromagnetic solenoid. [Prior Art] In general, an electromagnetic solenoid is used for a valve device in an antilock system of a vehicle. As shown in FIG. 5, a drive device of the electromagnetic solenoid outputs from a pulse generator 4 composed of a microcomputer. The voltage of the power supply 3 is applied to the electromagnetic solenoid 1 via the drive circuit 7 by the applied pulse. Here, the pulse width output from the pulse generator 4 is
The design is based on the case where the battery voltage is normal (12V to 14V), and does not consider changes in the electrical characteristics of the electromagnetic solenoid when the battery voltage changes. [Problems to be Solved by the Invention] Therefore, in the above-described conventional device, when the power supply voltage of the battery is reduced due to the failure of the alternator or the regulator or the frequent use of the self-starter, or when the power supply voltage is increased, Responsiveness when starting or releasing the electromagnetic solenoid changes. That is, as shown in FIG. 4A, the electromagnetic solenoid generally has a rising response time as the power supply potential increases, and, as shown in FIG. 4B, a fall response time as the power supply potential increases. Response time becomes longer. In addition, there is a characteristic that the lower the power supply voltage, the longer the response time at the rise and the shorter the response time at the fall. FIGS. 3 (A) and 3 (C) show the delay in the timing when the valve is actually turned on / off with respect to the input voltage when the power supply voltage is high and when the power supply voltage is low. Therefore, the hydraulic pressure intermittently operated by the valve driven by such an electromagnetic solenoid becomes as shown in FIG. 3B when the power supply voltage is high, and when the power supply voltage decreases, the hydraulic pressure shown in FIG. ), An abnormal state occurs. For the above reasons, there is a problem in that the flow rate and the pressure to be controlled change due to the timing of the valve operation being shifted. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made to provide a control circuit of a valve driving device that performs stable valve operation by compensating operation characteristics of an electromagnetic solenoid when a power supply voltage fluctuates. Subject. [Means for Solving the Problems] In order to solve the above technical problems, the present invention has the following configuration in a control circuit of a valve driving device that operates a valve by an electromagnetic solenoid. That is, in a control circuit of a valve driving device for operating the valve 2 by the electromagnetic solenoid 1, a pulse generator 4 for performing pulse modulation on a power supply 3 of the electromagnetic solenoid 1, a voltage detector 5 for detecting a power supply voltage, An addition / subtraction unit 6 for adjusting the width of the pulse output from the pulse generation unit 4 based on the output of the detection unit 5, and an electromagnetic solenoid drive circuit 7 connected between the addition / subtraction unit 6 and the electromagnetic solenoid 1. When the power supply voltage is low, the addition / subtraction unit 6 adds a compensation time, which is a difference time between the start delay time and the fall delay time of the electromagnetic solenoid 1, to the ON time of the pulse output from the pulse generation unit 4. When the power supply voltage is high, the compensation time is subtracted from the ON time of the pulse. It is needless to say that adding or subtracting the compensation time in the addition / subtraction unit is equivalent to adding a positive compensation time or a negative compensation time in the adder. [Operation] When the power supply voltage is low, the compensation time, which is the difference between the start delay time and the fall delay time of the electromagnetic solenoid 1, is added to the on-time of the pulse output from the pulse generation unit 4. When it is high, a predetermined compensation time is subtracted from the ON time of the pulse, so that the power supply voltage characteristics of the electromagnetic solenoid can be compensated even if the power supply voltage fluctuates, and the valve 2 can be controlled at regular timing. Embodiment An embodiment of the present invention will be described with reference to FIG. 1 and FIG. The electromagnetic solenoid 1 is for operating a valve 2, and this valve 2 is for a brake device. The power supply 3 of the electromagnetic solenoid 1 is an automobile battery. The pulse generator 4 outputs a drive pulse for the solenoid valve. The addition / subtraction unit 6 is controlled so that the pulse width output from the pulse generation unit 4 is adjusted by a signal from the voltage detection unit 5 that detects the power supply voltage. An electromagnetic solenoid drive circuit 7 is interposed between the addition / subtraction unit 6 and the electromagnetic solenoid 1, and the electromagnetic solenoid drive circuit 7 intermittently connects the power supply 3 to the electromagnetic solenoid 1 by a signal from the addition / subtraction unit 6. Works to connect. The addition / subtraction unit 6 adds a predetermined compensation time to the on-time of the pulse output from the pulse generation unit 4 when the power supply voltage is low, and adds the predetermined compensation time from the on-time of the pulse when the power supply voltage is high. It is designed to subtract. This compensation time is a difference time between the start delay time and the fall delay time of the electromagnetic solenoid 1, and
Start delay time and fall delay time of Ton and Toff respectively
Then, the compensation time (ΔT) becomes Ton−Toff. Here, the relationship between the power supply voltage and the compensation time is shown in FIG.
The compensation time is 0 at a power supply voltage of 12 V. If the power supply voltage is higher than this voltage, compensation on the negative side (shortening the pulse width) is performed, and the power supply voltage is lower than this voltage And the positive side (extending the pulse width) is compensated. In the embodiment shown in FIG. 2 (A), the compensation amount is continuously varied with respect to the level of the power supply voltage, and the compensation error becomes 0. However, the present invention is not limited to this example. The compensation amount may be switched between two stages as shown in FIG. If the switching is performed in two stages as described above, a high-precision A / D converter is not required, and the software is simplified, so that the operation can be performed at low cost. As described above, the opening / closing timing of the valve 2 is substantially constant regardless of the level of the power supply voltage and even when the startup and fall characteristics of the electromagnetic solenoid 1 are different, so that stable hydraulic controllability is obtained. [Effect of the Invention] When the power supply voltage is low, a compensation time, which is a difference time between the start delay time and the fall delay time of the electromagnetic solenoid 1, is added to the on time of the pulse for operating the valve 2, while the power supply voltage is low. When the pulse is high, the predetermined compensation time is subtracted from the ON time of the pulse. Therefore, even if the power supply voltage fluctuates, or even if the startup and fall characteristics of the electromagnetic solenoid 1 are different, the valve operation characteristics fluctuate. The valve operation can be always performed stably.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 show an embodiment of the present invention. FIG. 1 is a basic block diagram, and FIGS. 2 (A) and 2 (B) show the relationship between a power supply voltage and a compensation amount. FIG. 3 (A), (B), (C)
4 (D) is a time chart showing the operation characteristics of a general electromagnetic solenoid, FIGS. 4 (A) and 4 (B) are graphs showing the operation characteristics of a general electromagnetic solenoid, and FIG. FIG. 3 is a block diagram illustrating a driving circuit. 1 ... Electromagnetic solenoid, 2 ... Valve, 3 ... Power supply, 4 ... Pulse generation unit, 5 ... Voltage detection unit, 6 ... Addition / subtraction unit, 7 ... Solenoid drive circuit.

Claims (1)

(57) [Claims] In a control circuit of a valve driving device that operates the valve 2 with the electromagnetic solenoid 1, a pulse generation unit 4 that performs pulse modulation on a power supply 3 of the electromagnetic solenoid 1, a voltage detection unit 5 that detects a power supply voltage,
An adding / subtracting unit 6 for adjusting the width of the pulse output from the pulse generating unit 4 based on the output of the voltage detecting unit 5; an electromagnetic solenoid driving circuit 7 connected between the adding / subtracting unit 6 and the electromagnetic solenoid 1; The addition / subtraction unit 6 includes:
When the power supply voltage is low, a compensation time, which is the difference between the start delay time and the fall delay time of the electromagnetic solenoid 1, is added to the on-time of the pulse output from the pulse generator 4, and when the power supply voltage is high, A control circuit for a valve drive device, wherein the compensation time is subtracted from the ON time of the pulse.