PWM rectifier using indirect voltage sensing

A voltage source PWM converter can be used as the input stage to a four-quadrant variable-speed drive to give bidirectional power flow, and sinusoidal input currents with near unity power factor. The paper describes a method for line synchronisation and control of a PWM rectifier which uses indirect supply voltage sensing and gives fast update of line voltage phase angle whde rejecting distortion such as voltage notches. Indirect line voltage sensing allows the use of a standard AC motor drive as a PWM rectifier without additional hardware or line voltage connections. Details of the method used for synchronisation at start-up are given and experimental results demonstrating robust steady-state and dynamic performance are presented.