The balance capacitor’s control strategy of non-isolated three-level bidirectional Buck / Boost converter

Abstract:
With the development of the society, the performance requirement of the switching converter is getting higher and higher. Because the voltage balance on the two support capacitors on the high voltage side of the three-level Buck/Boost converter is the key to maintain the three-level waveform symmetry and the low voltage resistance of the three-level converter switching device. However, the switching device is not an idealized model ,the drive circuit is not symmetry, the delay circuit is different and another reasons will result in the two support capacitor’s voltage imbalance on the high voltage side of the three-level bidirectional Buck/Boost converter, so PI average voltage and adaptive average average strategies are adopted to solve the bias of the converter, and verify the feasibility of the average voltage strategy through simulation. and a 200W experimental prototype to verify the feasibility and effectiveness of the above control strategy.