Research On Parallel Operation Of Active Power Filters Based On Capacity Limitation Control Method

Proliferation of nonlinear loads has caused serise harmonic current and reactive power issues in power transmission systems. The active power filter(APF) using the fast switching converter to suppress the harmonic current, and compensate the reactive power, has been proved to possess good performance for dealing with these issues.However, single APF compensation capacity is limited by the capability of power device, it's important on reseasrching parallel operation of multi-APFs to improve the performance. Parallel operation of multi-APFs can achieve huge capability and improve the redundancy and flexibility of the compensation system. Parallel operation performance and implementation of the APF based on the capacity-limitation are explored in this paper.Firstly, the lastest develop situation of APF is stated. It is also discussed about how to detect harmonic and reactive power current. On researching on many control menthods of paralleled APFs, a new control method based on capacity-limitation is proposed.Advantages of the proposed appfoach include high flexbility for extending system capacity, high reliability due to no control interconnection, reducing power capacity demand of single APF ,high modularity due to indentical APFs ,stable reactive power and harmonic current sharing and its performance is insensitive to parameters mismatch of APFs, cost-effective due to modularization, and so on. Some simulation waves are also demonstrated to approve its feasibility.Finally, two single-phase APFs are designed and implemented. The control circuits and paralled operation program based on DSP are designed. Researching and analysing of the experiments are finished basically at the case of low voltage.