Double-loop control and stability analysis based on three-phase Buck-Boost inverter

To develop and apply renewable energy, one of the key technologies is that a kind of inverter outputting high quality sinusoid signals to power network is required. This paper proposed a three-phase buck-boost inverter, which can generate a three-phase ac output voltage larger than the dc input one. Its basic configuration is introduced, and the system stability of open-loop is analyzed by constructing small-signal modeling. The double-loop control strategy is designed in turn and the closed-loop system stability is analyzed. Simulation is conducted to confirm the theoretical analysis. The output voltage of three-phase buck-boost inverters can track the reference quickly and accurately, and they achieve a high immunity to external perturbations such as input voltage and output load disturbances. The simulation tests show the good transient response, robustness and high reliability, which are agree with the theoretical analysis.