High-Frequency Pulsating DC-Link Three-Phase Inverter Without Electrolytic Capacitor

In this work it is presented a generalized converter configuration for a high-frequency pulsating DC-link inverter for three-phase applications. The configuration consists of a DC/DC-pulsating converter cascaded with a DC-link capacitor-less three-phase inverter. Due to the absence of a DC-link electrolytic capacitor, the presented inverter guarantees a long life-time and high power density. The DC/DC-pulsating converter aims to generate the high-frequency pulsating DC-link waveform profile which has to be synchronized with the three-phase inverter PWM. Comparing to the conventional PWM, the harmonic spectrum of voltages is the same, but the pulsating DC-link three-phase inverter presents reduced switching losses due to the fact that only one leg commutes during a switching period while the other two legs keep clamped in high or low. Details of control strategy and modulation are presented. Experimental results of a 1.6 kW prototype are presented to validate the effective operation of the proposed structure.