Smart Nonlinear Energy Feedback Power Electronic Load to Simulate Power Quality Problems

Abstract

This paper proposes a design approach for an energy feedback power electronic load (PEL) based on back-to-back voltage source PWM converters. It can simulate not only constant linear loads but also a class of nonlinear loads to simulate power quality problems. The rectifier side and the inverter side are decoupled in control by using a DC capacitor. The rectifier side is responsible for tracking designed current commands to achieve the designed load characteristics, and based on the characteristics of the current commands, a multi-resonant controller plus state feedback controller was designed by using the internal model principle. The inverter side employs an LCL filter with active damping to control the phase of the grid-connected current, enabling energy to feed back to the grid. A simulation model of this PEL is established in Simulink software, and the simulation results verify the effectiveness of the proposed control strategy.