The Study Of Intermediate Frequency Power Supply Control Circuit Base On FPGA

In recent years, the technique of FPGA is focused on and applied in numerical control system widely because of its superiority. The tcchniques of FPGA on intermediate frequency power supply is discussed in order to build a safe and intermediate frequency induction heating environment in this dissertation.The control circuit of system is investigated in this paper. First of all, base on the available documents at home and abroad on this subject, the pricinple of induction heating, the development of induction heating and disadvantages of control circuit are analyzed. Secondly, the operating principle and operating state of intermediate frequency power supply are analyzed. Finaly, a new type of control strategy is proposed based on the programmable logic device.In this paper, some of the concepts and technology about intermediate frequency induction heating system are introduced .At the same time, the principles and feasible studies of modules are deeply analyzed. The design flow of FPGA is introduced, and the control circuits which are necessary of hardware are designed.In this paper, there are three very important key problems. First of all, the method of control rectification circuit is explicated base on FPGA. It adopts double sharp pulse to control the SCR, the output voltage is adjusted by contrlolling the rectification angle. Therefore, it is very easy to change the value of power. Secondly, the all digital phase-locked loop module is explicated base on FPGA and analyzed its operating principle. A new type method is proposed to improve the phase-locked loop. At the same time, the scope of phase-locked loop is increased. The phase-locked loop can be followed the load changes at the maximum to find the resonant frequency. The module of swept circuit is designed base on the digital phase-locked loop. It is very easy to change the scope of swept cirucit by changing the design documents, which will be meat the needs of different frequencies. Finally,the periphery circuits of hardware design are introduced, such as the acquisition circuit of single, the circuit of feedback signal, the circuit of PI and the protection circuit. All the circuits are designed and simulated.Eventually, the main control circuits are integrated into a FPGA chip by the technique of FPGA, and the system is much smaller and steadier. Therefore, the control of intermediate frequency induction heating control system will be more intelligent and more safety to operate, so our aims are achieved. The findings show that it is very feasible to realize digital intelligent control system with the technique of FPGA.