Research On High-power And High Frequency Multiple-frequency Inverter Supply Of 700kHz

Induction heating power supplies are widely used in all walks of life, these processes are the need for high-power high-frequency power. At present, it uses the MOSFETs as high-frequency phase-power devices. As the MOSFET with the low level voltage and current, the capacity to enhance its output power is limited. This paper researches on an 700kHz double-frequency induction heater based on MOSFET. The main circuit is parallelling MOSFET in each of the traditional MOSFET and time-sharing controling, that is, in the the two cycles of inverter output, each MOSFET works one cycle, the operating frequency is 350kHz. To further enhance the output power, the use of MOSFET technology in parallel to increase current capacity, thereby enhancing the output power. Power regulating method is a new time-sharing PDM power control method of multiple frequency inverter is presented in this paper, which is based on PDM and time-sharing. Then, it analysed the structure and working principle of multiple frequency inverter. The implementation of the power control method is based on complex programmable logic device CPLD as its core. The use of VHDL hardware language programming, module structure and Quartus II simulation verified its accuracy. Meanwhile, a closed-loop system of current and power was designed, and the overall closed-loop block diagram of the power is proposed. Finally, through analysis and comparison of various MOSFET driver circuit, a dedicated MOSFET driver IC IXDD430 is choosed to complete driver circuit design. At the same time, protection and the formation of deadtime , starttime and compensationtime circuit are introducted. Finally a 700kHz multiple frequency inverter is made. MOSFETs'operating frequency is 350kHz, the inverter's operating frequency is 700kHz. Control core using Altera's EPM1270CPLD produce the control drive pulse of time-sharing control of multiple frequency inverter, the use of TI's TMS320F2812 DSP implement closed-loop power control, simplifying the system architecture. The experimental results show that multiple frequency inverter can effectively improve the power supply frequency, so as to meet the needs of more applications.