Line voltage sensorless three phase PWM converter by tracking control of operating frequency

Much research about a power line voltage sensorless PWM converter has been presented from the view points of the simplicity and the reliability of the control system. Most schemes need some calculations to estimate the power line voltage using circuit parameters. In this paper, we propose a novel control strategy of the three phase PWM converter by tracking control of the operating frequency based on the power balance of the converter. The system is composed of the direct PWM control loop of the instantaneous active and reactive current. The features of the proposed PWM control system are simplicity without sensing the line voltage, high reliability with poor dependence of the circuit parameters, high efficiency and fast response etc.