Research & Design On The Series Active Power Filter Based On DSP System

With the development of national economy and the enhancement of people's living standard, more and more strict requirements for power quality are needed by electrical power users because the problems caused by voltage quality and harmonics are becoming increasingly serious. APF(Active Power Filter) has been a key project in power electronics application technology, as the most effective method to solve harmonic and reactive power pollution, and improve the power quality. Now, most of the engineering equipment that have been put into operation use centralized way of compensation, and focus on the power system, but R & D and operation for the distributed power quality compensation device for the user side is very small. Therefore, the development of harmonic compensation technology for the customers is imminent.Since the circuit structure characteristic of Series Active Power Filter (S APF) is researched in this paper, triumph over the other types on compensating voltage type harmonic source, which concerned by the customers. Two crucial technologies of the active Power filter on harmonic detection and the control of PWM inverter are analyzed in this paper comprehensively. At the end of the paper, a single-phase SAPF system scheme realized by the combination of DSP's software and hardware is proposed.By analyzing Instantaneous reactive power theory based harmonic detecting method, this paper discusses the improved dq method three-phase harmonic voltage detection principle and its realization based on synchronous rotating coordinate transformation. After analysis the characteristics of three-phase harmonic detection, this Paper proposes a kind of realization method of single-phase SAPF harmonic detection. With simulation of MATLAB/Simulink, the feasibility of this two algorithm is proved, The simulation result shows that the algorithm can effectively guarantee the real-time quality and accuracy of the detection result.Based on the analysis of the three-phase SVPWM technique and its algorithm, a single-phase voltage vector space transform were introduced, then, a single-phase SVPWM technique and its realization method were put forward. In order to guarantee the stability of capacity voltage on the DC side of inverter, PI closed-loop which can satisfy DC bus voltage control requirements in a variety of load conditions is introduced.Using MATLAB/Simulink, the simulation models of three-phase and single-phase system of SAPF are built respectively, and harmonic compensation effect under various conditions is analyzed comprehensively. The simulation results verify that this two SAPF have excellent harmonic voltage compensating capability.In addition, this paper separately describes hardware realization method which is composed of the microprocessor units of control system,the data sampling unit,DAC conversion unit and synchronization sampling signal generating unit. According to the hardware scheme of control system, the software realization scheme is given, which includes:the design flow chart of the main program,its interrupt service routine,harmonic separating algorithm and the implementation of SVPWM waveform.