A Slide Mode Observer and Disturbance Observer Based Control Method for the Voltage Sensorless Control of oc hree-Phase Rectifier

Owing to the high-power factor, low-current harmonics, controllable dc-link voltage, and bidirectional energy flow, The PWM rectifier has been rapidly developed. However, by using the traditional control strategy, the output voltage of the dc-link suffers from the undesired voltage fluctuation under varying loads. In addition, the utilization of voltage sensors increase the cost and decreases the system reliability. Thereby, an improved fractional-order power sliding mode observer (FOP-SMO) for the voltage sensorless control of the PWM rectifier is proposed to acquire accurate grid voltage. Furthermore, to mitigate the dc-link voltage fluctuation, an extended-state observer is established to estimate and compensate the load disturbance. In simulations, the high-precision grid voltage observation and dynamic control performance are achieved by using the composite control strategy.