Emulation of nonlinear loads with energy regeneration

This paper presents an nonlinear load emulator for testing AC power supplies and power equipment with energy regeneration capability. The structure is based on back to back three-phase PWM voltage source inverter (VSI). To achieve power balance, an independent control strategy for both PWM VSI is proposed. Experimental results are presented to verify the emulator performance draining a linear and nonlinear current from an autotransformer and regenerating the energy to the utility grid.