JPS6258122B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is a relay. This invention relates to a control device for various actuators having an electromagnetic mechanism such as a solenoid, and is intended to provide a control device for an electromagnetic mechanism that reduces excitation coil loss even when power supply voltage fluctuations are large, and provides sufficient performance during initial attraction. It is.

Conventionally, there has been a device of this type as shown in FIG. In the figure, 1 is a hysteresis converter that inputs a current command signal S _I and a current feedback signal S _O to obtain an on-off control signal S ₁ , and 2 performs logical inversion of the on-off control signal S ₁ to generate an on-off control signal S ₂
3 is a PNP transistor controlled by on/off control signal _S2 , 4 is excitation control signal _S3
5 is a freewheeling diode, 6 is a coil current detection resistor, 8 is an excitation coil of an electromagnetic mechanism, and 9 is a power source. Furthermore, 71,7
2 and 73 are resistors forming a hysteresis converter, which are a setting resistor, a hysteresis resistor, and a hysteresis resistor, respectively.
It is a feedback resistance. 74 and 75 are transistors 3,
4, each of which is a base resistance.

Next, the operation of the conventional device shown in FIG. 1 will be explained with reference to FIG. 2. In the figure, A is the excitation control signal S _S which is a signal for whether or not to excite the excitation coil 8, B is the current command signal S _I and the excitation coil current I _O , and C is a time chart showing the excitation coil voltage _VO . be. The excitation coil 8 is excited between the time t _ON and the time t _OFF .

At time t _ON , the exciting coil current I _O is zero,
Transistors 3 and 4 both turn on from t _ON to t ₁
In the period , it increases with the electric circuit time constant of the excitation coil 8. The current command signal S _I always shows a constant value, and since there is comparator hysteresis, the exciting coil current increases by the hysteresis I _OM
At the time _t1 , the transistor 3 is turned off. Then, the exciting coil current passes through the freewheeling diode and attenuates. Then, at time t ₂ , contrary to the case of increase, I _ON is smaller than the current command signal S _I than the comparator hysteresis, the transistor 3 is turned on again, and the coil current I _O increases. The above operation is repeated until time t _OFF .
In this way, although the on/off ripple of the transistor 3 is included, current control is performed that follows the constant current command signal S _I. In this way, even when the power supply voltage fluctuates greatly, constant current control is performed to minimize excitation loss. However, in the conventional control system, the coil current is limited by the power supply voltage E and the excitation coil impedance at the time of initial attraction, so the current at the time of initial attraction is insufficient and the response is poor.

It is an object of the present invention to provide a control device that improves performance during initial attraction and reduces excitation loss by controlling the necessary minimum excitation coil current.

Therefore, the initial excitation current is increased by coordinating the excitation coil impedance and the power supply, and by obtaining the rising differential of the excitation control signal S _S and adding it to the current command signal of the hysteresis converter. Constant current control is performed according to the

An embodiment of the present invention will be described below with reference to FIG. In the figure, 1 is a hysteresis converter,
2 is an inverter, 3 is a PNP transistor, 4 is
5 is a freewheeling diode, 6 is a current detection resistor, 8 is an excitation coil, and 9 is a power supply. 10 is a differential element consisting of a resistor 101 and a capacitor 102. 71 is a setting resistor, 72 is a hysteresis resistor, 73 is a feedback resistor, and 74 and 75 are base resistors of transistors 3 and 4.

FIG. 4 is an explanatory diagram of the operation in the case of the embodiment shown in FIG. 3, where A shows the excitation control signal S _S and B shows the addition result of the current command signal S _I and the differential current command signal S _D. A certain composite current command signal S _ID and exciting coil current I _O are shown, and C shows a time chart waveform of the coil voltage V _O.

As in the conventional example, the transistor 3 is controlled to follow the differentially compensated composite current command signal S _ID by on/off control. If the excitation current is increased during the period from time t _ON to t _W in the figure (indicated by a first-order lag time constant), the electromagnetic force increases and the initial attraction characteristics can be improved.

After attraction, control is performed to follow the current command signal S _I , which is the holding current, as in the conventional case.

In this way, the performance at the time of initial suction can be improved, and the subsequent holding can be controlled with the minimum necessary current, so that the drawbacks of the conventional method can be eliminated.

In the embodiment shown in FIG. 3, a resistor and a capacitor are used as differential elements, but it goes without saying that a logic circuit may be used to obtain a pulse width signal of t _W from time t _ON at the time of initial attraction.

FIG. 5 shows a configuration diagram of a circuit for obtaining the rising edge differential of the excitation control signal _{S S} using the monostable multivibrator 103 and the AND element 104 as a logic circuit. shows a time chart waveform with the differential current command signal S _D.

As described above, according to the present invention, it is possible to obtain a control device for an electromagnetic mechanism that improves performance during initial attraction, performs minimum current control necessary for subsequent holding, and has low excitation loss.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional embodiment, and Figure 2 is a diagram of the configuration of a conventional embodiment.
3 is a configuration diagram showing an embodiment of the present invention. FIG. 4 is an explanatory diagram of the operation of FIG. 3.
The figure shows a modification of the differential element, and FIG. 6 is an explanatory diagram of the operation of FIG. 5. In the figure, 1 is a converter, 2 is an inverter, and 3
is a PNP transistor, 4 is an NPN transistor,
5 is a freewheeling diode, 6 is a current detection resistor, 8 is an exciting coil, 9 is a power source, and 10 is a differential element.

Claims (1)

[Claims] 1. In a control device for an electromagnetic mechanism that performs constant current control in response to a constant current command signal, a differential element is added to obtain a differential current command signal that is a rising differential signal of an excitation control signal indicating whether or not excitation is necessary, and the constant current A control device for an electromagnetic mechanism, characterized in that the sum of a command signal and the differential current command signal is used as a command signal for an exciting coil.