A Compound Strategy to Optimize the Output Characteristics of Mid-Frequency Inverter

To improve the stability and output voltage quality of inverter, an new repetitive control strategy for 400Hz Constant Voltage Constant Frequency (CVCF) inverter has been proposed . Based on active damping, this strategy damps the oscillations on the output LC filter of inverter under unload or light load. Using state-observer to weaken the impact of time delay in digital control, a 5.5 kW one-phase 400Hz inverter prototype by this strategy has been tested.The result shows that low THD (about 1.5%) with inductive loads and fast error convergence (2 fundamental periods) can be achieved by this strategy which can be demonstrated to be brief and effective.