An Improved Deadbeat Control Method for Second Harmonic Current Reduction in Two-Stage Single-Phase Inverter

Abstract

The instantaneous output power of the two-stage single-phase inverter pulsates at twice the output frequency, resulting in a large number of second-harmonic current (SHC) in the front-end dc-dc converter, which impairs the function of the dc-dc converter. To reduce the SHC and avoid complex closed loop design, an improved deadbeat control (DBC) method, which integrates the voltage proportional integral loop into the inner current deadbeat control loop, is proposed in this paper. It intends to directly control the inductance current of the front and rear converters respectively, so as to reduce SHC and make the DC bus capacitor provide almost all pulsating power. In order to solve the problem of delay compensation in DBC, a method of one-beat-delay tracking is used to improve the control stability. Finally, the effectiveness of the proposed improved DBC method is verified by the real-time hardware-in-loop tests.