Research On The Control Strategy Of Induction Heating Power Supply Based On Three Phase Current PWM Rectifier

Induction heating power supply technology has many advantages,such as green,energy efficiency,easy to automate.With the continuous improvement of China’s industrial level,induction heating technology will be widely used in various occasions.However,traditional induction heating power supply generally use semi-controlled or uncontrollable power devices,so there are many problems,such as low efficiency and high harmonics.Therefore,the three phase current source PWM rectifier(CSR)is applied to the rectifier of the induction heating power supply because that the three phase CSR can adjust the DC side voltage and current from zero,so it can realize direct power regulation of the DC side,and the three phase CSR can operate with any power factor.The topology of the three-phase CSR,the control strategy and the design of induction heating power supply based on the three-phase CSR are analyzed and studied.Finally,the induction heating experimental prototype based on the three phase CSR operate stablely.The main content of the full text is as follows:First of all,the topology and operating characteristics of three phase voltage source PWM rectifier(VSR)and three-phase CSR is studied.And the three-phase CSR with obvious advantages and more research significance is chosen to apply to the induction heating experiment platform.In addition,the mathematical model of the three-phase CSR and the method of space vector pulse width modulation are analysed deeply,which provides theoretical basis for the research of the control algorithm and the establishment of experimental platform.Secondly,the control strategy of three-phase CSR is studied for the induction heating characteristics of fast tracking and robustness and the problem of resonant peak caused by the adoption of three-phase CSR.And the strategy of a PI controller with adjustable power factor for the current outer loop and a nonlinear and active damping composite controller for the current inner loop is adopted.This control strategy can not only achieve rectifiers running at any power factor,but also improve the robustness of the system because the nonlinear and active damping controller is adopted in the current inner loop.Moreover,the addition of active damping makes the system overcome the disadvantage that the nonlinear controller can not suppress the resonant peak of the LC filter.And the control effect and the selection of the virtual resistance value are analyzed in depth by the amplitude and phase characteristics curve.Through simulation and experimental waveform analysis,it is proved that the control strategy can achieve good control effect.Finally,PC104 industrial computer and FPAG is used to build the induction heating power supply prototype.Then the communication interface of PC104 is designed.And after that the three-phase CSR PWM drive signal generation is completed by the program in the FPGA.The phase lock control and power adjustment is completed by SG3525 and peripheral circuit.Through the analysis of the waveform of the experimental prototype,it is proved that the design has good working effect.