Optimal pulse width modulation for current source converter based static exciter

This paper presents a new optimal pulse width modulation (OPWM) technique for the current source converter (CSC) which is used as part of the static exciter. The reduction of total harmonic distortion (THD) of ac side line current is considered as the control objective of the proposed OPWM. This is formulated as an optimization problem in this paper, and particle swarm optimization (PSO) algorithm is applied to solve the nonlinear transcendental equations. Furthermore, in order to make this CSC based exciter fulfill more roles than the traditional static exciter, a decoupled loop control technique is adopted to design a controller for this exciter. The simulation results demonstrate the effectiveness of the proposed OPWM technique and the control strategy.