Electromagnetic heating apparatus and heat control circuit and heat control method thereof

Abstract

The invention discloses an electromagnetic heating apparatus and a heat control circuit and a heat control method thereof. The heat control circuit comprises a voltage zero-crossing detection unit, a resonance heating unit, a rectifying and filtering unit, a power switch tube, a driving unit, a discharging unit and a main control unit, wherein the discharging unit is used for performing discharging treatment on the collector voltage of the power switch tube; one end of the discharging unit is connected with the collector of the power switch tube while the other end of the discharging unit is grounded; the main control unit is connected with the voltage zero-crossing detection unit, the driving unit and the control end of the discharging unit separately; and when the main control unit controls the electromagnetic heating apparatus to operate in a low-power interrupted heating way, the discharging unit is controlled to stop discharging in a heating section, and the discharging unit is controlled to perform discharging in the heating stop section so as to enable the voltage of the collector to be lowered to a preset value when the power switch tube is heated and switched on in the next time, so that the power switch tube is controlled to be switched on at quite low collector voltage in the interrupted heating process, so as to avoid hard switch-on of 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 device, a heating control method of an electromagnetic heating device and an electromagnetic heating device. Background technique [0002] At present, the electromagnetic resonance circuit of a single IGBT (Insulated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor) usually adopts a parallel resonance method, and when using the resonance parameters to realize the high-power operation of the induction cooker, if it operates in the continuous low-power segment, it will The following problem occurs: [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 i...

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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 the low power is realized in the heating mode with open duty ratio, that is, the intermittent heating mode is adopted, due to the existence of the filter capacitor, the IGBT will be hard turned on when the next cycle is turned on, which will easily cause the IGBT to burn out

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