Research On 3D-SVPWM Control Method For D-STATCOM

In recent years,with the rapid development of high-technology, especially the information technology, in distribution system more and more loads are sensitive to power quality, and the harm caused by power quality problems have become more prominent. As an important member of FACTS, D-STATCOM has played a significant role in reactive power compensation and harmonic suppression, and has gradually been in a hot research. For compensating reactive power unbalanced loads and harmonic,negative-sequence and zero-sequence current in distribution power system,control method of three-phase four-wire D-STATCOM is mainly studied.Three-Dimensional Space Vector Pulse Width Modulation (3D-SVPWM) strategy is chosen due to the structural characteristics of four-leg D-STATCOM. The principle and digital control algorithm of three-dimensional space vector modulation, based on theαβγcoordinate, therefore, are described and derived in detail respectively. The theoretical analysis show that three-dimensional space vector modulation,compared with traditional hysteresis control and triangular carrier control, has a higher utilization of DC voltage and lower harmonic content,and is more easily digital realization.With the development of Digital Signal Processor(DSP), the execution time will also be perfectly acceptable.The D-STATCOM which uses 3D-SVPWM control strategy has been simulated under different loads.The results suggest that D-STATCOM has good performance in harmonic suppression,reactive power compensation,balancing three phase asymmetric loads and neutral current compensation,and also has a good dynamic response capability in the case of mutation loads.Finally, with the developing platform CCS of DSP TMS320F2812, control program of D-STATCOM which adopts 3D-SVPWM control strategy is compiled, and experiment research under unbalanced loads is done with a builded experimental platform. Experimental results verify that 3D-SVPWM strategy and harmonic current detection adopted by D-STATCOM are feasible and validity.