Research On Improved SVPWM Control Strategy For Three-Phase Six-Switch Rectifier

With the continuous development of power electronics technology on the "green road",as the main source of harmonic pollution,power electronic converters are required to have low harmonic content of the power grid and high energy utilization rate of the power grid.Therefore,PWM rectifiers with Power Factor Correction(PFC)have become one of the research hotspots in power electronics applications today.As a typical PWM rectifier,the three-phase six-switch rectifier has many advantages such as fewer switching devices,simple circuit structure and bidirectional flow of energy,so it is widely used in high-power fields.Typical control methods for three-phase six-switch rectifiers include single-cycle control,average current control,and Space Vector Pulse Width Modulation(SVPWM).However,the traditional SVPWM control strategy has problems such as large switching loss and high design cost due to redundant working modes and large calculations.Therefore,in order to reduce the number of switching cycles in the switching cycle and improve the working efficiency,it is of great theoretical significance and engineering value to study the optimization of the traditional SVPWM control strategy in the redundant working mode.Firstly,this dissertation introduces the current research status of various PFC circuit topologies and control strategies,and analyzes and compares their applications and characteristics.Secondly,this dissertation introduces the working principle of three-phase six-switch rectifier,and establishes the mathematical model.The basic principle of SVPWM technology is introduced in detail,and according to system controllability,the minimum modal SVPWM control strategy is proposed based on SVPWM.Besides,it has built MATLAB/Simulink simulation models of the minimum modal SVPWM control strategy,and the simulation results have constructed to verify correctness and feasibility of the theory.Then,the TMS320F28335 is selected as the control chip of the three-phase six-switch rectifier.The hardware design and software design of the three-phase six-switch rectifier are introduced.The hardware design part includes the main circuitparameter design,the component selection,the control circuit design;the software design mainly introduces the system program initialization,the related register configuration and the algorithm implementation of the PID control and the minimum modal SVPWM modulation strategy.Finally,a three-phase six-switch rectifier experimental prototype with a rated power of 10 KW is constructed.The traditional SVPWM control strategy and the minimum modal SVPWM control strategy are tested respectively.The experimental results show that the minimum modal SVPWM control strategy has higher efficiency and verifies the theoretical feasibility.