A Novel Transformerless Single-Stage Single-Inductor Buck-Boost Inverter with Leakage Current Suppression Capability

This paper proposes a single-stage single-inductor Buck-Boost inverter (SIBBI) with leakage current suppression capability. By controlling the DC-side electrolytic capacitor voltage to remain balanced, common-mode leakage current can be eliminated. Compared to traditional half-bridge Buck-Boost inverters, the SIBBI uses only one inductor for energy regulation, thereby improving the utilisation rate of the inductor during both positive and negative half-cycles, reducing losses and costs, and further enhancing power density. The SIBBI employs a multi-modal control algorithm based on dead-beat control (DBC), ensuring that only one switch is in the high-frequency state at any given time, thereby reducing switching losses. Additionally, when the capacitance of the electrolytic capacitor decreases, the SIBBI can operate in pure Buck-Boost mode, thereby extending the lifespan of the electrolytic capacitor. This makes it suitable for photovoltaic inverter applications.