Research On High Performance And High Frequency Induction Heating Power Supply

Induction heating power supplies with the merits of highly efficiency, cleanness, flexible control and high heating speed have been widely applied in industry. At present, improving frequency, power and reducing line-side current harmonic of power supply is the research hotspot and open question. The thesis fixed on the systematic project of high performance and high frequency inductiom heating power supply, meanwhile, conducted a theoretical and emulational validation for parts of the system, including three-phase current source PWM rectifier(CSR), LLC resonant inverter and alternate control scheme of inverters.In the thesis, time domain and frequency domain models of three-phase current source PWM rectifier were founded in three-phase static coordinate system, the generation and distribution mode of SPWM modulation signal was presented; and on the basis of analyzing control strategies for three-phase current source PWM rectifier, indirect current control strategy was emphatically studied, control system was designed and feasibility condition of unity power factor on line-side was presented.The current transformation capacity and adaptability for malfunction of LLC resonant inverter were researched by analyzing its structure and properties. And it was proved that the use of LLC resonant circuit could make inverters paralleled easily and also make alternate control scheme implemented easily by comparing the output difference of two inverter units such as output voltage amplitude error, phase error, and trigger asynchrony when the inverters were paralleled. Then the parameter selective principles of LLC resonant inverter were summarized and the parameters calculation was completed.Finally, the feasibility of circuit topology, the validity of control scheme and the rationality of parameters designation were verified by simulation.