Research On New Control Strategy Of Single-Phase PWM Rectifier In Car Charger

In recent years,with the rapid development of power electronics technology,power converters have played a key role in applications such as renewable energy,power storage systems,and automotive drives.In particular,single-phase PWM rectifiers with high power factor,low harmonic content,and bidirectional flow of energy have attracted high attention to low-power photovoltaic(PV)integration and electric vehicle charger.On the one hand,PWM rectifier has gradually replaced the traditional rectifier devices,effectively reducing the amount of reactive energy and a large number of harmonic pollution on the power grid.On the other hand,controller of the single-phase PWM rectifier is one of the core technologies that ensure the system can operate normally and steadily,it has more and more practical value for the controller design.It has been a research hotspot of scholars and engineers.In this paper,the research status and application of PWM rectifier are introduced firstly.Next,a mathematic model of the single-phase PWM rectifier.According to the mathematical model,the traditional control strategy is simulated and the waveform is analyzed in depth,such as fixed switching frequency of the transient current proportional integral(PI)control,proportional resonant(PR)control and d-q coordinate system voltage directional current control,and we will find that the traditional control method has a steady state current error,very sensitive to the voltage change on the network side and slow response speed.Then,in view of the deficiencies of the above traditional control methods,two new control strategies are proposed in this paper: model predictive current control based on the optimal switching sequence and the sliding mode variable structure control,and in-depth theoretical analysis and mathematical model is derived.For the model-predicted current control of the optimal switching sequence,this method can not only show the dynamic behavior at the time of the future,but also can provide a constant switching frequency when dealing with the system constraints,and it has good robustness and stability.For the sliding mode variable structure control,overall design of the algorithm has nothing to do with the system parameters and external disturbances,and it can solve the deficiency of traditional control strategy,while it has stronger robustness.In view of the two new control methods,we set up a single-phase PWM rectifier system control model in MATLAB and perform simulation waveform analysis to verify the feasibility and superiority of the new control method in PWM rectifier applications.Finally,according to the previous simulation research,based on TI's floating-point digital signal processor TMS32F28335 chip,the new control algorithm is experimentally verified on a single-phase PWM rectifier experimental platform,and the experimental results prove the validity and correctness of the new control strategy proposed in this paper.