Active Disturbance Rejection Decoupling Control of Grid-Connected PWM Converter

With the increasing penetration of renewable energy integrated into the power system and increasing demand for flexible power conversion, pulse width modulated (PWM) converter is being extensively used in many areas. Either working in the rectification of inversion mode, the PWM converter is usually connected to the grid. Appropriate control strategies are essential in guaranteeing the performance of the grid-connected PWM converters for various applications. There exist some adverse disturbances such as parameter variations, source and load changes, measurement disturbance that can affect the control performance in the grid-connected PWM converter system. The active disturbance rejection control (ADRC) is a promising candidate controller to address the issues caused by disturbances. This paper investigates the ADRC for decoupling control of the grid-connected PWM converter. When the converter works as a rectifier, the main control objective is the DC voltage and reactive power (or power factor). When the converter works as an inverter, the main control objective is the AC current and power factor. Based on modeling analysis, different disturbances in the system can be lumped as the total disturbance and be estimated by an extended state observer (ESO) and then be compensated by the dynamic feedback in an appropriately designed controller. The simulation results demonstrate the feasibility of analysis and effectiveness of the proposed controller in dealing with disturbances.