added power

• To that large amount and distributed signal phase electrical source , the most effective method is adding power factor correction ( rfc ) stage inside . it can be eliminate the problem at the sources . with the fast development of pfc in these years , one of focus in the pfc research is putting forward new topology
  谐波是电力系统中的主要污染源，对于数量多而且分散的中小功率单相电源系统，最理想的方法就是在电源内部采用功率因数校正( pfc )措施，从根本上消除谐波源，因而功率因数校正技术在近几年来得到了飞速的发展，其中功率因数校正技术研究的一个热点问题就是新的拓扑结构的提出。