| With the development of power electronics, large-scale use of inverters and other nonlinear loads, the problems of harmonics pollutions are becoming increasingly serious in power grid. Using active filter (Active Power filter-APF) technology to suppress harmonics has become a trend today. APF can be used to suppress the harmonic of grid, improve current waveform in power line, but also compensate reactive power of grid. APF device also has an excellent performance of dynamic compensation.Aiming at limitations of majority of APF harmonic current detection methods can only detect total harmonic current, based on the instantaneous reactive power theory, a method can be proposed that detects total harmonic current, but also random harmonic current. This method can be used for three-phase three-wire system, and can be used for three-phase four-wire system.The paper analyzes in detail the principles of space vector pulse width modulate (SVPWM), gives digital method. Further combining the above harmonic current detection method and SVPWM control strategy to compose active power filter system, and carry out overall numerical simulation. Simulation results show that the system can accurately and rapidly detect and compensate the harmonic current.Based on the programs of current detection and compensation, design of the whole APF system for software and hardware is finished. The main part of the hardware test circuit is built respective and the experimental study is completed. Integration control system software process, harmonic current detection,SVPWM and other major interruption procedures are developed and achieved in the digital signal processor (DSP TMS320LF2407A), given the experimental waveforms and analysis.Finally, in a factual perspective, under certain conditions, Matlab optimization toolbox is used without coordinates transformation to design APF. This method has the control circuit to achieve relatively simple compared to traditional method, and has better filtering effect. |
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