提高高压变频器功率因数的方法研究

单元串联式的6kV高压变频器由移相变压器、功率单元和控制器三部分组成。采用矢量法计算移相变压器的各电压参数,力图使电压与电流同相位来提高功率因数,而后对功率单元的拓扑结构进行改进。考虑到双PWM电路自身存在的经济性、可靠性等方面的不足,提出一种基于BUCK-BOOST的三相PFC整流+PWM逆变电路,通过Matlab仿真得出两种电路整流部分的电压波形与交流侧的功率因数,对比发现该三相PFC整流电路所需的器件少,控制电路简单,且消除了交流侧电流的冲击波,将不控整流的功率因数大大提高,且具有良好的可靠性与经济性。

Research on an Approach for Improving Power Factor of High-Voltage Converter

A 6KV unit-series high-voltage converter is composed of the phase-shifting transformer,power unit and controller.A vector method is used to calculate various voltage parameters of phase-shifting transformer.The voltage and current at same phase position should be ensured to increase power factor and then to improve the topological structure of power unit.Taking into account the deficiencies of double-PWM circuit with respect to economy and reliability,this paper proposes a three-phase PFC rectification＋PWM contravariant circuit based on BUCK-BOOST,and obtains voltage waveforms in rectification part of circuit and power factor in AC side by simulation of Matlab.It is found out by comparison that this circuit needs less components and control circuit is simple.It eliminates current shock wave in AC side,greatly improves the power factor of uncontrolled rectification,and has good reliability and economy.