Voltage balance control of Vienna-type rectifier using SVPWM based On 60° coordinate system

In this paper, a space vector PWM (SVPWM) algorithm based on 60° coordinate system is proposed for Vienna-type I rectifier, which can greatly simplify the calculation of the dwelling time of the three nearest vectors which synthesize the reference vector. In addition, the switching state equation is introduced to control the neutral-point voltage balance and the appropriate degrees of factor f is decided, which adjusts the working time of positive and negative small vectors to reduce unbalance level of neutral point voltage between output capacitors, and then an optimal zero sequence component is found to guarantee neutral point voltage balance. Without calculating a lot of trigonometric functions, the scheme based on 60° coordinate system is computationally extremely efficient. The results of simulation and experiment verify the proposed control algorithm.