IH heating control circuit and method based on alternating-current zero-crossing point zero-voltage starting

Abstract

The invention relates to an IH heating control circuit and method based on AC zero-crossing point zero-voltage starting, and the method comprises the steps: after an AC power interface is connected with a commercial power, enabling an alternating current to sequentially pass an LC filter circuit and a rectifier to be rectified, and outputting a forward pulsating voltage; when the alternating-current voltage crosses a zero point, enabling the forward pulsating voltage to be reduced to zero voltage; controlling a drive circuit to trigger and drive the switch tube to be conducted at the zero voltage point, enabling the forward pulsating voltage to pass through a resonance circuit composed of the electromagnetic induction coil, the resonance capacitor and the switch tube to form an electromagnetic induction heating loop to complete heating power starting, and controlling the drive circuit to be matched with a synchronizing signal to continuously control on-off of the switch tube to achievecontinuous heating. According to the invention, an alternating current zero-crossing signal is monitored in the process from stopping heating to recovering heating each time, the switching tube is recovered and turned on at a zero-crossing point, and zero-voltage turn-on in the whole working process is realized in cooperation with the resonance circuit so as to adapt to the working environment requirement of quick start and stop.

Description

technical field [0001] The invention relates to the technical field of electromagnetic heating control circuits, in particular to an IH heating control circuit and method based on AC zero-crossing and zero-voltage startup. Background technique [0002] Such as figure 1 As shown, it is the heating control circuit of the traditional single-tube induction cooker. The basic principle of the circuit is: the mains power is rectified after the pre-filter, and after rectification, the DC voltage is output through the post-stage filter. The DC voltage is used for the electromagnetic induction coil circuit. A switching tube is connected in series in the circuit, and the switching tube is controlled by the control circuit to realize the on-off control of the heating circuit. When the switch tube is in the off state, the open circuit behind the rectified filter capacitor has an infinite equivalent resistance. Therefore, the AC voltage is formed at point A (the input sampling point of ...

AI Technical Summary

Problems solved by technology

Disadvantages: Add a regulator tube, a triode and a control circuit

Disadvantage: add a relay and corresponding control circuit

Can only be heated intermittently at regular intervals in half cycles

[0010] The third method: use two resonant capacitors and use relays to switch between full power and low power. At full power, the two resonators are connected in parallel and work with a larger resonant capacitor. At this time, the resonant reverse voltage is low and can output higher power, but Low power can not resonate zero-crossing zero-voltage switch-on

When the power is low, it is necessary to disconnect a resonant capacitor and use a small resonant capacitor to work. At this time, the resonant back pressure is high, and the power is limited by the back pressure. It cannot output a large power, but there is enough energy to resonate through zero to achieve smaller heating power.

Disadvantages: add a relay, a capacitor

[0011] Among the above-mentioned existing solutions, the first solution has the lowest cost, but the noise is large; the second solution is the second, and the noise is relatively small; the third solution is the most expensive, but the noise is the least

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