Electromagnetic heating cooking device and its heating control circuit and low-power heating control method

Abstract

The invention discloses an electromagnetic heating cooking device, and a heating control circuit and a low power heating control method thereof. The low power heating control method includes the steps of controlling the electromagnetic heating cooking device to perform the intermittent heating by using a wave losing method when a low power heating command is received; detecting a voltage zero crossing signal of an input AC power supply; when the electromagnetic heating cooking device is controlled to switch from the stop heating zone to the heating zone, outputting a first control signal to a drive unit in a first time period before the zero crossing point according to the voltage zero crossing signal, and after the zero cross point, outputting a second control signal to the drive unit in a second time period, wherein the voltage amplitude of the first control signal is equal to the voltage amplitude of the second control signal and the pulse width of the first control signal is smaller than the pulse width of the second control signal. The impact current is reduced at the time of its hard turn-on by changing the pulse width of the control signal of the power switch tube, thereby reducing the risk of damage to the power switch tube.

Description

technical field [0001] The invention relates to the technical field of electromagnetic heating, in particular to a heating control circuit of an electromagnetic heating cooking device, a low-power heating control method of an electromagnetic heating cooking device, and an electromagnetic heating cooking device. Background technique [0002] At present, in products such as induction cookers and electromagnetic heating rice cookers, the electromagnetic resonance circuit of a single IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) usually adopts a parallel resonance mode, and when using the resonance parameters to achieve high-power operation of the induction cooker, If operating in the continuous low power segment, the following problems will occur: [0003] (1) The IGBT voltage is turned on ahead of time, and the moment of turning on will cause the peak value of the IGBT transient current to be high, which will easily exceed the IGBT current peak va...

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Problems solved by technology

[0003] (1) The IGBT voltage is turned on ahead of time, and the moment of turning on will cause the peak value of the IGBT transient current to be high, which will easily exceed the IGBT current peak value specification limit and damage the IGBT;

[0004] (2) The IGBT will generate serious heat, and it is necessary to strengthen the heat dissipation of the IGBT (such as increasing the heat sink, increasing the fan speed, etc.) to meet the temperature rise requirements of the IGBT;

[0005] (3) If low power is achieved in the duty cycle heating method, that is, the intermittent heating method is adopted, due to the existence of the filter capacitor, there will be a hard turn-on phenomenon when the IGBT is turned on in the next cycle, which will easily cause the IGBT to burn out

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