Sistemas de conversão CC/CA monofásicos isolados com desacoplamento de potência baseados em dupla ponte ativa.

Abstract

In this work, two single-phase isolated DC/AC converters with active power decoupling capabilities are proposed, analyzed and developed. Thse converters are based on the Dual Active Bridge converter. The first converter is a voltage-fed type and employs a full-bridge on the DC side and a two-level cycloconverter on the AC side. The decoupling port is inserted on the DC side by connecting inductors to the bridge legs and a decoupling capacitor. An open loop control strategy validates the decoupling of the power oscillation and the injection of current into the power grid with a high power factor. The second converter integrates two full-bridge PWM rectifiers by coupling the respective filter inductors, resulting in a four-port system that balances the power flow depending on the two duty cycles and the phase angle between the voltages of the full-bridges. The analysis of the operating modes and power expressions is performed using the high frequency current waveform. The simulation and experimental results in stationary conditions corroborate the accuracy of this analysis. Afterwards, a closedloop control strategy is implemented to validate the operation as a microinverter connected to the grid, allowing the performance of the converter (harmonic distortion, power factor and eficiency) to be evaluated as a function of the delivered power.