Design Of Single-phase Dynamic Voltage Restorer

With the rapid development of' industry,more and more non-linear,impact load is used,caused by voltage drop,instantaneous power failure and other power qualitry problems have become a common concern of power users.The Dynamic Voltage Restorer(DVR)device is a new type of power electronic device that protects sensitive loads from voltage drop,ramming,and so on.Series transformer type dynamic voltage recovery device is simple,effective,widely used in power quality control.Therefore,this paper has been studied for the series transformer type dynamic voltage restorer.In this paper,the basic structure and principle of the dynamic voltage restorer are analyzed,and the influence of the series transformer on the whole system is introduced in detail.As a result of the use of a series transformer,in fact,will produce leakage inductance,the paper discusses the leakage inductance on the filter design and the overall system performance.It has also been determined that the use of a single-phase rectifier bridge to provide an input DC voltage for the inverter can provide sufficient energy and duration.Fast and accurate detection of the system voltage drop characteristics of the dynamic voltage regulator is a prerequisite for the operation.In this paper,we introduce and simulate the RMS value detection method and the dqO detection method based on the instantaneous reactive power theory,and design a digital low-pass filter to improve the response speed of the system under the premise of maintaining the detection accuracy.The simulation results show that the improved RMS method has better real-time performance than the traditional RMS method.In the research of dynamic voltage restorer control strategy,the advantages and disadvantages of different SPWM methods are compared,and the voltage output formula using unipolar frequency doubling method is deduced,and the distribution of harmonics is explained.Then,based on PID classical control algorithm,the single voltage closed loop and the voltage and current double closed loop are simulated.The advantages and disadvantages of different control strategies in steady state performance and dynamic performance are analyzed with different simulation results.Finally,we introduce the three kinds of compensation methods commonly used in the vector diagram to illustrate the economic cost of different compensation methods.In the end.this paper designs a dynamic voltage controller based on TMS320F28335 digital control,and designs the main circuit scheme and controls the construction and programming of the experimental board.The experimental results show that the dynamic voltage recovery device designed in this paper has good compensation effect.which can meet the requirement of voltage drop compensation in small power,and lay the theoretical and practical foundation for further research.