Indirect current control adjustable power factor current source PWM converter

Current source PWM converter (PWM-CSC) are expected to replace diode and thyristor phase-control rectifier that bring in rich harmonics in some occasions, advantages include perfect power factor and dc current source performance. However, due to inherent nonlinear and compact couple characteristics, the converter is usually controlled by complex direct current control strategies, these methods are very difficult in realizing power factor regulation and energy feedback. This paper proposed an indirect current control technique based on dq coordinate. In the proposed technique, dc output of the converter is used as active current reference value of the network current, reactive current of the network is regulated by the produce of the active current reference value and tgφ, then the ac-link current disperse equations of PWM-CSC are used to find instant control variable that control network current of the converter indirectly. Consequently, active power and reactive power of the converter are controlled, and adjustable power factor and energy feedback are obtained. This paper discussed the steady operation-range of the converter, and the conclusion that the reactive power is limited by the actual active power is drawn.