A quasi-Z-source active neutral point clamped inverter topology employing symmetrical/unsymmetrical boost modulation control scheme for renewable energy resources

Abstract

This paper proposes a bipolar quasi-Z-source active neutral point clamped inverter (QZS-ANPCI) topology.It acts as a buck/boost inverter (3-phase, 3-level) to integrate renewable energy resources under their fluctuatingDC voltages. We propose a symmetrical/unsymmetrical boost modulation control technique to mitigate the DC-linkunbalance voltage problem in an ANPC inverter. This worthwhile control technique exploits voltage-current closedloops on AC and DC sides to regulate the desired parameters. Moreover, the constant boost control (CBC) modulationhas provided a switching sequence that generates a symmetrical/unsymmetrical full shoot-through (FST) state forboosting input DC voltage in the proposed inverter. Detailed loss and efficiency analysis is carried out to show itssuperior performance under the proposed scheme. Furthermore, the total harmonic distortion (THD) of the proposedQZS-ANPCI meets IEEE Standard-519. Simulink/MATLAB (MathWorks, USA) and PSIM (Powersim, USA) softwareprograms are used to simulate the proposed topology. To verify the theoretical proposals and simulation results, we havedeveloped an experimental prototype setup (1 kW). Both simulation results and experimental data show satisfactoryagreement and support the theoretical postulates.