JPS5933712A - Power controller - 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 Field of the Invention The present invention relates to a power control device that controls energization of a load using a relay.

Conventional configuration and its problems Conventionally, when controlling the energization of a heater connected to an AC power source using a relay, a clock pulse is generated from the AC power source, and the clock pulse is counted to create an arbitrary time to drive the relay coil. However, in this method, since the reference clock pulse is generated from the AC power supply, the timing of driving the relay coil is constant with respect to the AC power supply, and as a result, the timing of opening and closing of the relay contacts is Also, the timing of opening and closing the relay contacts is fixed to a certain phase of the AC power supply, and that phase is 9
If it is close to 00 or 2700, it will always open and close at the maximum current value. 1. If you always open and close with the positive or negative of the AC power supply, it is the same as using a DC power supply, which has the drawback of dislocation of the contacts and uneven lifespan.

OBJECTS OF THE INVENTION The present invention aims to provide a highly reliable power control device with little variation in the lifespan of relays.

DESCRIPTION OF THE INVENTION The present invention averages out the lifespan of relay contacts by changing the relay drive timing with respect to the phase of the AC power source.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In Figure 1, 1 is an AC power supply, ■ is a constant voltage power supply circuit,
(2) is a zero volt pulse generation circuit, 111 is a relay drive signal generation circuit, (2) is a relay drive unit, RL is a relay, D2 is a capacitor for absorbing surge voltage of the relay coil, and H is a heater. The constant voltage power supply circuit (2) includes resistors R1, R2, diodes D1. Capacitor CI, constant voltage diode ZD
1, a relay drive signal generation circuit 111
is constituted by the circuit shown in FIG. 2.The relay drive section (2) is constituted by resistors R3, R4, ) transistor Q1, and the relay RL is constituted by relay coils RL1. +
It is composed of a J-ray contact RL2.

Next, the operation will be explained. The AC power supply 1 includes a diode D1. of the constant voltage power supply circuit 1. The voltage is rectified and smoothed by the resistor R1 and the capacitor C1, resulting in an unstable voltage, which becomes the power source for the relay RL. This unstable voltage is made constant by a resistor R2 and a constant voltage diode zD1, and serves as a power source for the relay drive signal generating section (2). The zero volt pulse generation circuit ■ is
The vicinity of zero voltage of the AC power source 1 is detected and an odd number of zero volt pulses are counted (FIG. 3b). Next, the ON time generation circuit counts an even number of zero volt pulses to set the QN time of the relay. As a result, the output waveform of the ON time generation circuit is d, the first rise and fall of the waveform correspond to the rise of AC power supply 1, and the second rise and fall of the waveform correspond to the fall of AC power supply 1. . Hereinafter, the timing of the rise and fall of the output waveform of the ON time generation circuit changes alternately with the rise and fall of the AC power supply 1 every cycle. Next, the output of the ON time generation circuit is output from the delay circuit O~4.
added to. Here, the delay time of delay circuit O is 0. Assuming that the delay time of delay circuit 1 is 1ms, the delay time of delay circuit 2 is 2ms, the delay time of delay circuit 3 is 3ms, and the delay time of delay circuit 4 is '14m5, the output waveform of the ON time generation circuit is , and are output to the respective delay circuits with a delay of the above-mentioned respective times. On the other hand, the output of the period generating circuit becomes the clock of the ring counter.

Immediately after the AC power supply 1 is generated, this ring counter is instantaneously 5 times due to the action of the resistor R5 and capacitor C2.
・The R3T terminal becomes LOW, a reset is applied, and the output ○
~4 are all LOW, but due to the clock from the period generator circuit, 0 → 1 → 2 → 3 → 4 → 0 → 1
→2......and outputs 0 to 4 become HIGH in sequence 0
Outputs 0-4 of the ring counters are added to NANDo-4 together with outputs of delay circuits 0-4, and the outputs of NANDo-4 become inputs of NAND6. As a result, in one cycle of the output of the ON cycle generation circuit immediately after AC power generation/generation, only the output of the ring counter 0 is HIGH, so the delay circuit 0
The output waveform becomes the output of NAND5. In the next cycle, only the output 1 of the ring counter is HIGH, so the output waveform of the delay circuit 1 becomes the output of the NAND5. Similarly, the output of the NAND 5 sequentially outputs the output waveforms of the delay circuits ◯ to 4 every cycle (e-0-e-4). This output is applied to the base of transistor Q1 via resistor R3, and is applied to coil RL of relay RL by transistor QIK.
1 is energized and controlled. As a result of the above, the relay coil is 1
0N-O at positive and negative timing of AC power supply 1 every cycle
FF. Furthermore, it is ON in the range of 0 to 4 mB for 1 ms each.
-The OFF timing changes.

Therefore, if the AC power supply 10 frequency is 60Hz and Zuno1. Ba,
The half cycle is about 8ms, and the relay coil is connected to AC power supply 1.
Between zero voltage and 4 ml+, ○N with approximately equal probability
-0FF.

Effects of the Invention As is clear from the above explanation, according to the present invention, the ON/OFF timing of the relay coil does not depend on the specific phase or polarity of the AC power source, so the timing of opening/closing of the relay contact can be adjusted. Also, the AC power supply will no longer be biased toward a specific phase polarity, and relay contacts will always open and close near the peak of the AC type, or always open and close near zero voltage, which will shorten the life of the relay. It is of great industrial value, as it can prevent problems such as extremely large variations, stabilize contact life, and improve reliability.

[Brief explanation of drawings]

FIG. 1 shows a power control device 7 showing an embodiment of the present invention.
- Figure 2 is a block diagram of a part of the same circuit.
FIG. 3 is a voltage waveform diagram of the main parts of the circuit. 1...AC power supply, H...heater. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure H

Claims (1)

[Claims] It is equipped with a relay contact that controls the energization of the load connected to the AC power source, and a relay drive circuit that controls the opening and closing of this relay contact.This relay drive circuit maintains a constant cycle with respect to the phase and polarity of the AC power source. A power control device configured to open and close relay contacts.