Research And Design Of 3kW Single-Phase PWM Rectifier

The transformation and application of electric energy bring us convenience,but also bring serious harmonic and reactive pollution to the power system.Because single-phase PWM rectifier has high power factor,energy bidirectional flow,dynamic response speed,output voltage adjustable and low input current total harmonic distortion are more and more widely used in power conversion systems.With the gradual popularization and promotion of new energy and distributed energy storage,the improvement of power quality requirements has put forward higher requirements on the harmonic content and stability of single-phase PWM rectifiers.Therefore,this thesis mainly studies single-phase PWM rectifiers used in the field of household distributed energy storage,and explores a medium and small power rectifier with high power density and low harmonic content.In addition,the performance of the PWM rectifier is improved and improved from the direction of modulation mode and control strategy,so that its performance in distributed energy storage applications is improved.The main research work is summarized as follows:Firstly,the topology and control strategy of single-phase PWM rectifier are analyzed,and the applicable occasions and advantages and disadvantages of different topologies and control algorithms are compared.The system scheme of voltage-type single-phase PWM rectifier is designed,and the mathematical model is established to analyze the main techniques.Parameters,modulation methods,and operating modes.Secondly,the double closed-loop control strategy is studied in detail,and the control model of the voltage outer loop is analyzed.The traditional multiple current control strategies are analyzed.For the traditional PI control,there is dynamic response difference,hysteresis current control,and the switching frequency is not fixed and predicted.Current control has the disadvantages of large computational complexity,and an improved predictive current control algorithm in rotating coordinate is proposed.Based on the traditional predictive current control strategy,the algorithm introduces a rotating coordinate to control the active current and reactive current separately,and replaces the current error calculation with another form,effectively reducing the intermediate variable.The calculation reduces the traditional predictive current control algorithm and improves the reliability of the algorithm.Finally,the main circuit parameters of single-phase PWM rectifier are calculated.Based on this,the proposed current control algorithm is simulated and compared.The simulation results verify the validity and correctness of the theoretical analysis part.The experimental platform of 3kW single-phase PWM rectifier was developed.The hardware and software design of the platform was given.The hardware solution to suppress the starting impulse current was proposed.Then the improved algorithm is compared with the traditional PI control algorithm.The effectiveness of the algorithm is proved by soft start experiment and stability experiment.