阅读说明：本技术 一种双频感应加热电源及其控制方法 (Dual-frequency induction heating power supply and control method thereof ) 是由 余维江 王卫刚 刘晶 于 2019-10-31 设计创作，主要内容包括：本公开涉及一种双频感应加热电源及其控制方法,包括：控制器、过零检测电路、三相全桥整流电路、单相全桥逆变电路、谐振电容、加热线圈,单相全桥逆变电路包括第一晶闸管、第二晶闸管、第三晶闸管和第四晶闸管,第一晶闸管和第四晶闸管为一对管,第二晶闸管和第三晶闸管为一对管,控制器与第一晶闸管、第二晶闸管、第三晶闸管和第四晶闸管的控制端以及与过零检测电路连接,控制器在控制某一对管导通时,并在确定过零检测电路检测到该对管导通输出的交流电的电压在第若干次过零点以后,触发另一对管导通,这样,单相全桥逆变电路就能够输出包括超音频谐振电流和中频谐振电流分量的交流电,实现晶闸管双频感应加热,以满足大功率加热应用场景的需求。(The present disclosure relates to a dual frequency induction heating power supply and a control method thereof, including: the controller is connected with the control ends of the first thyristor, the second thyristor, the third thyristor and the fourth thyristor and the zero-crossing detection circuit, when the controller controls the conduction of a certain pair of the thyristors, and after the zero-crossing detection circuit detects that the voltage of the alternating current output by the conduction of the pair of the thyristors is at a first zero-crossing point, the other pair of the thyristors is triggered to be conducted, so that the single-phase full-bridge inverter circuit can output the alternating current comprising the superaudio resonant current and the intermediate-frequency resonant current component to realize the dual-frequency induction heating of the thyristors, so as to meet the requirement of high-power heating application scenes.)

1. A dual frequency induction heating power supply comprising: a three-phase full-bridge rectifying circuit, a smoothing reactor, a single-phase full-bridge inverter circuit, a resonant capacitor and a heating coil, the single-phase full-bridge inverter circuit comprises a first inverter bridge arm and a second inverter bridge arm which are connected in parallel, the first inverter bridge arm comprises a first thyristor positioned on the upper arm and a second thyristor positioned on the lower arm, the second inversion bridge arm comprises a third thyristor positioned on the upper arm and a fourth thyristor positioned on the lower arm, wherein the first thyristor and the fourth thyristor are a pair of transistors, the second thyristor and the third thyristor are a pair of transistors, the positive output end of the three-phase full-bridge rectifying circuit is connected with the smoothing reactor, the anode of the first thyristor and the anode of the third thyristor, the cathode of the second thyristor and the cathode of the fourth thyristor are connected with the output negative end of the three-phase full-bridge rectifying circuit; the resonant capacitor and the heating coil are connected in parallel to a connection point of the first thyristor and the second thyristor and a connection point of the third thyristor and the fourth thyristor, and the resonant capacitor and the heating coil are characterized by further comprising: a controller and a zero-crossing detection circuit,

the controller is respectively connected with the control ends of the first thyristor, the second thyristor, the third thyristor and the fourth thyristor and the zero-crossing detection circuit, the zero-crossing detection circuit is connected with the resonant capacitor in parallel, the controller is used for controlling the conduction of a pair of transistors in the first inverter bridge arm and the second inverter bridge arm and determining that the zero-crossing detection circuit detects that the voltage of alternating current output by the single-phase full-bridge inverter circuit is at a first zero-crossing point for a plurality of times, the other pair of transistors in the first inverter bridge arm and the second inverter bridge arm are triggered to be conducted, and the single-phase inverter full-bridge circuit outputs alternating current comprising super-audio frequency resonant current and intermediate-frequency resonant current components.

2. The dual-frequency induction heating power supply of claim 1, wherein the controller is configured to trigger the conduction of the other pair of transistors of the first inverter bridge arm and the second inverter bridge arm after controlling the conduction of one pair of transistors of the first inverter bridge arm and the second inverter bridge arm and determining that the zero-crossing detection circuit detects that the alternating current output by the single-phase full-bridge inverter circuit is at a first zero-crossing point for several times, and the triggering of the conduction of the other pair of transistors of the first inverter bridge arm and the second inverter bridge arm includes:

the controller is used for triggering the conduction of the other pair of transistors in the first inverter bridge arm and the second inverter bridge arm after the zero-crossing detection circuit detects that the voltage of the alternating current output by the single-phase full-bridge inverter circuit is at the second zero-crossing point and before the third zero-crossing point.

3. The dual-band induction heating power supply according to claim 2, further comprising a transformer, wherein one incoming line terminal of the primary side of the transformer is connected to a connection point of the first thyristor and the second thyristor, the other incoming line terminal of the primary side of the transformer is connected to a connection point of the third thyristor and the fourth thyristor, and a secondary outgoing line terminal of the transformer is connected in parallel to the zero-cross detection circuit, the resonant capacitor, and the heating coil.

4. The dual-frequency induction heating power supply of claim 3, wherein a first commutation inductor and a second commutation inductor are connected in series between the first thyristor and the second thyristor, a third commutation inductor and a fourth commutation inductor are connected in series between the third thyristor and the fourth thyristor, a connection point of the first commutation inductor and the second commutation inductor is connected to one line inlet terminal of the transformer primary, and a connection point of the third commutation inductor and the fourth commutation inductor is connected to the other line inlet terminal of the transformer primary.

5. A control method of a double-frequency induction heating power supply is applied to the double-frequency induction heating power supply, and the induction heating power supply comprises a controller, a three-phase full-bridge rectifying circuit, a smoothing reactor, a single-phase full-bridge inverting circuit, a zero-crossing detection circuit, a resonant capacitor and a heating coil; the single-phase full-bridge inverter circuit comprises a first inverter bridge arm and a second inverter bridge arm which are connected in parallel, the first inverter bridge arm comprises a first thyristor positioned on an upper arm and a second thyristor positioned on a lower arm, the second inverter bridge arm comprises a third thyristor positioned on the upper arm and a fourth thyristor positioned on the lower arm, the positive output end of the three-phase full-bridge rectifier circuit is connected with the smoothing reactor, the anode of the first thyristor and the anode of the third thyristor, and the cathode of the second thyristor and the cathode of the fourth thyristor are connected with the negative output end of the three-phase full-bridge rectifier circuit; the first thyristor and the fourth thyristor are a pair of transistors, and the second thyristor and the third thyristor are a pair of transistors; the resonant capacitor and the heating coil are connected in parallel to a connection point of the first thyristor and the second thyristor and a connection point of the third thyristor and the fourth thyristor, and the controller is respectively connected with the control ends of the first thyristor, the second thyristor, the third thyristor and the fourth thyristor and the zero-crossing detection circuit, wherein the method comprises the following steps:

controlling one pair of transistors in the first inverter bridge arm and the second inverter bridge arm to be conducted;

and determining that the zero-crossing detection circuit detects that the voltage of the alternating current output by the single-phase full-bridge inverter circuit is after the second zero-crossing point and before the third zero-crossing point, triggering the conduction of another pair of transistors in the first inverter bridge arm and the second inverter bridge arm, and outputting the alternating current comprising the ultrasonic frequency resonance current and the medium-frequency resonance current component by the single-phase full-bridge inverter circuit.