JPS5929779A - Control system for electro-magnetic pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control system for an electromagnetic pump used to generate fluid pressure for driving an actuator. However, in order to generate this fluid pressure, an electromagnetic pump that performs reciprocating motion in response to a pulse current passing through the windings is suitable. In order to adjust the output of the electromagnetic pump, it is necessary to control the output of the electromagnetic pump.

Figure 1 is a pulse current waveform diagram showing the conventional control method, where (5) shows when the duty ratio is changed, ■) shows when the peak value is changed, and (0 shows when the frequency is changed). In this case, the output of the electromagnetic pump is controlled by changing the energy corresponding to the integral area of the pulse current and distributing this energy to the windings of the electromagnetic pump.

However, in (a), if the duty ratio is small,
There is a risk of pulsation in the output of the electromagnetic pump, and the type (ω) requires a current control element to control the peak value, and the internal loss of this cannot be ignored, and the type (C) has a high frequency. In this case, the flowing current decreases due to the inductance of the winding, resulting in disadvantages such as a decrease in the output of the electromagnetic pump.

The present invention has the purpose of fundamentally eliminating the drawbacks of the conventional method, and has developed an extremely effective electromagnetic method that changes the duty ratio of the pulsed current while using a pulsed current of a constant peak value and a constant period. The details of the present invention will be described below from FIG. 2 showing an embodiment.
Explaining II0 Figure 2 is a waveform diagram of a pulse current.The period t is constant, the peak value is constant, and only the duty ratio is changed.If the duty ratio is small, When the output of the electromagnetic pump decreases and the duty ratio is large, the output of the electromagnetic pump increases.

However, the period t is selected to such an extent that pulsation does not occur in the output of the electromagnetic pump even when the duty ratio is small. It is a circuit diagram showing an example of a circuit, in which a self-running multi-pipe rake (hereinafter referred to as a free-running multi) AM and a monostable multi-pipe rake (hereinafter referred to as a mono-multi) MM are provided, and a self-running multi AM generates a Nockles signal with a constant width according to the period determined according to the values of the resistor R1, R-made capacitors CI and C2, and a monomultiply signal is generated depending on the MM is driven, variable resistor RV
A pulse signal (with a pulse width corresponding to the value of the artificial capacitor C3) is generated.

For this reason, we set the nox signal generation period of the free-running multi-AM to the period t in Fig. 2, and if we change the variable resistor 1 (Vi), we can generate a constant period and a variable duty ratio as shown in Fig. 2. The pulse signal is 0!!, 7”C, resistor R
The output of the monomulti MM is given to the pace of the transistor Q1 through the circuits of 3 and R4! Finally, the transistor Q1 is turned on in response to the output between the monomultiple circuits.

On the other hand, a reference bias is applied to the ↓υ non-inverting input of resistors Iζ5 and R6, and transistor Ql and resistor R7
A differential amplifier A is provided to which the power supply +Vc is applied to the inverting input via the inverting input, and when the transistor Q1 is turned on, the output of the amplifier becomes high level, so this output is connected to the resistor R8.
is applied to the base of transistor Q2 via E, turning on transistor Q2, and current flows from power source E to the winding of the electromagnetic pump.
A resistor R9 is inserted on the emitter side of the transistor Q2, and since the terminal voltage of this resistor is given as negative feedback to the inverting input of the differential amplifier A via the resistor R+offi, the current flowing to the transistor Q2 is The wave height value is always kept constant.

However, the diode D in parallel with the winding is a shock absorber for absorbing the back electromotive force generated by the winding LK.

Therefore, as shown in Fig. 2, the winding LK has a constant period t and a constant peak value, and a pulse current with a duty ratio determined by the value of the variable resistor RV- is passed through the winding LK, and the output of the electromagnetic pump is determined according to the duty ratio. is controlled.

Since the period t is constant, the influence of the winding inductance is always constant, and even if the duty ratio is changed, the current value does not change, and the peak value is constant, so the loss of transistor Q2 Since Q is constant, all transistors Q2 can be selected economically.

However, in Fig. 3, a self-excited pulse oscillator may be used instead of the free-running multi-AM, and the same is true even if the variable resistor RV is fixed and the capacitor Cs is switched. The present invention can be modified in various ways, such as omitting Ql.

In the above explanation, [:! The obvious advantage of the present invention is that the output of an electromagnetic pump can be controlled stably and economically, so it has a remarkable effect when controlling electromagnetic pumps not only for driving actuators but also for various other uses. I get it.

[Brief explanation of the drawing]

Fig. 1 is a waveform diagram showing a conventional example, Fig. 2 and subsequent figures show embodiments of the present invention, Fig. 2 is a waveform diagram, and Fig. 3 is a circuit diagram. Running multi pipe~ri), M
M...Mono multi (monostable multivibrator),
Ql, Q2...Transistor, A...
Differential amplifier, RV...variable resistance ＼゛, L...
Winding, R1~Rho...Resistor 2゛1, Cl-03...Capacitor, fist...-Period. Patent disciple: Yamatake Honeywell Co., Ltd. Agent Masaki Yamakawa (1 person)

Claims (1)

[Claims] In a method of controlling the output of the electromagnetic pump by passing a pulse current to the windings of an electromagnetic pump and changing the energy of the pulse current, the pulse current having a constant peak value and a constant period is used to control the output of the pulse current. An electromagnetic pump control method 0 characterized in that the output of the electromagnetic pump is controlled by changing the duty ratio of the electromagnetic pump.