Research On 350kHz High Power Time-sharing Phase-shifting Control Inverter Power Based On IGBT

At present,the frequency of solid-state induction heating power supply that is higher than 100kHz are basically using MOSFET. For the capacity of MOSFET is small, high-power induction heating power require devices in parallel and in order to eliminate the inherent parasitic diode reverse recovery characteristics of the negative, quickly restore diodes must be used in series. The reliability and efficiency are reduced by using many devices. Moreover in the same power and frequency the cost of IGBT just 1/2~1/3 of MOSFET. However, the IGBT switching losses is large, especially at high-frequency switch with tail current state ,which limits the frequency of IGBT. At present, the switch frequency of IGBT can to be 100kHz at zero current switch (ZCS).Because low frequency of IGBT device. This paper presents a new inverter topology through four IGBTs parallel to achieve high-frequency, thereby, ensuring high-power induction heating power on the premise of increased frequency. In addition, for induction heating system parameters changed with the time,the environment and the temperature, this paper studied the use of current synchronous zero-crossing frequency tracking technology and designed in CPLD, in this way the inverter always maintain in the power factor approximation at a state work, and power efficient operation.An induction heating power supply which used the way of high-frequency was designed, the power of which is 350kHz and 1kW for the inverter. In the implementation process, the study of time-sharing phase-shift based on the DSP+CPLD , simulation software for the download test, as well as the protection of IGBT driver circuit, the use of current synchronous zero-crossing frequency tracking technology were designed in CPLD. It gave the whole blue print of the system, the inverter control block, drivering circuit, protective circuit, the simulation and experimental results.