VSS control of unity power factor [of boost rectifiers]

Three-phase PWM power converters, specifically voltage source inverters (VSI) are possibly the most frequently used power converters for applications such as industrial motor control, robotics, air conditioning and ventilation, uninterruptible power supplies, electric vehicles, etc. With introduction of recent standards on limiting harmonic pollution of electrical power distribution systems, three-phase PWM power converters are being considered as prime candidates for interfacing high-power electronic equipment to power supply lines. In this applications, these power converters can provide input currents without distortion and with unity power factor. In this paper, the idea of using a VSS control strategy of a boost rectifier in the sliding mode is described. A new discrete-time control algorithm has been developed by combining VSS and Lyapunov design. It possesses all the good properties of the sliding mode and avoids the unnecessary discontinuity of the control input, thus eliminating chattering which has been considered as a serious obstacle for the application of VSS. A unified control approach for output DC voltage and input AC currents based on the discrete-time sliding mode is developed. All theoretical issues are verified by simulation and experiments.