Dsp-based Single-phase Series Hybrid Active Power Filter Design Study

In the recent years, because of the developments of Hi-Tech and emergence of new-type power loads, the traditional power load structure has been changed enormously. On one hand, they have caused the serious pollution to power supply quality ;On the other hand, they also have put forward higher request to the power supply quality. As a result, the technology of restraining harmonic with active power filter to raise power quality rapidly becomes a focus in the power electronic study field at present.As one of the most efficient methods, application of the active power filter is broadened to promote the power quality in power system more than to restrain harmonic produced by custom load. Aiming at custom side, this paper designs a power quality compensation device of single-phrase hybrid series active power filter (HSAPF) which can efficiently eliminate harmonic produced by load and improves the quality of power supply, and studies comprehensively two crucial technology of the active power filter on harmonic detection and the control of PWM inverter. At the end of the paper, A HSAPF system scheme realized by the combination of DSP's software and hardware is proposed.To solve the problem existing in single-phase harmonic detection , this paper proposes a kind of realization method of single-phase harmonic detection which bases on microprocessor. With simulation of MATLAB software, the feasibility of this algorithm is proved , and the effect of harmonic detection which is determined by the type, cut frequency and step of digital low pass filter , is analyzed. The simulation result shows that the algorithm can effectively guarantee the real-time quality and accuracy of the detection result.To control output of the PWM inverter, a improved hysteresis control strategy to control APF inverter is given, which can ameliorate t dynamic response and precision of compensation; In order to guarantee the stability of capacity voltage on the DC side of inverter, a mathematical model of capacity charge control on the DC side of inverter is set up. On the same time, PI loop is also introduced. All of these insure the dependability of capacity discharging and charging. The exactness of all algorithms is proved by the simulation of MATLAB.In addition, this paper separately describes principles and hardware realizationmethod which is composed of the microprocessor units of control system > the data sampling uniK 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 harmonic separating algorithm, the main program and its interrupt service routine. At last, the paper summarizes and prospects the work of the whole work .