Simplified Input Voltage Sensorless Vector Control for PWM Rectifiers

Input voltage information is essential lift vector control of three-phase active pulse-width modulated (PWM) rectifier. Input voltage sensors impact cost, size and reliability of the PWM rectifier. Existing input voltage sensorless methods either involve extensive mathematical computations to estimate the input voltage or have a control structure significantly different from that of conventional vector control. This work proposes an input voltage sensorless control of PWM rectifier which retains the simplicity of vector control and also reduces the computation requirement. Modelling and analysis of the rectifier system with the proposed phase locked loop (PLL) are presented. The design procedure for the PLL is detailed, and is validated through frequency domain studies. Performance of the proposed method is compared with that of conventional sensor based vector control through simulations and experiments. The responses of both are found to be almost indistinguishable while the proposed method is shown to require reduced computational effort