Research On Digital Control Of Three-phase PFC Circuit

Since the twenty-first century,the rapid development of power electronics technology,is widely used in switching power supply,inverter and other power electronic equipment and household electronic devices.Most of the power electronic devices through the rectifier and the grid interface,the input current is usually contains pulsed current signal waveform and more harmonic components,resulting in the power factor is low,causing a serious harmonic Wave pollution to the power system.The technology of Three-phase PFC can effectively solve these problems,so it has become a hot topic in recent years.In this paper,the high power factor correction circuit of digital control is designed according to the basic principle of three-phase PFC.Firstly,the characteristics of various Three-phase PFC topologies are analyzed.The Three-phase Six-switch voltage rectifier is selected as the research object,establishing the mathematical model of switch function,and realizing the conversion of variables from three-phase static coordinate system to a two-phase rotating coordinate system;Secondly,the digital control strategy of the system is studied,and done the design of double closed-loop PI controller based on feedforward decoupling current loop and voltage outer loop.At the same time,The SVPWM algorithm is chosen to generate the PWM wave that controls the power switching device of the rectifier circuit,the application of space voltage vector modulation method in three-phase voltage rectifier is realized.and the model is built under the Simulink environment,which proves the rationality and feasibility of the control strategy.Finally,choose the TMS320F2812 as main control chip to design the hardware and software circuit,the hardware design including the three-phase six switch rectifier circuit,zero crossing detection circuit,sampling circuit and driving circuit,and in the CCS5.5.0 integrated development environment,the main program,SVPWM program and AD conversion program and other software design are completed.In this paper,Using the TMS320F2812 as the main control chip to build the experimental platform,and the circuit prototype with the high power factor correction function is designed to verify the feasibility of the theoretical analysis and design.