Improved Transformerless Inverter With Common-Mode Leakage Current Elimination for a Photovoltaic Grid-Connected Power System

Abstract: Aiming at the leakage current problem in the transformerless three-level grid-connected inverter, an equivalent model of the common-mode circuit is established, and the analysis shows that in addition to the common-mode voltage, the fluctuation of the neutral point voltage is also an important reason for the leakage current. Therefore, an improved DSVPWM strategy is proposed, which introduces a non-basic vector in the same sector as the synthesized reference vector. This not only makes up for the shortcomings of the traditional DSVPWM strategy that cannot balance the neutral point voltage due to the lack of redundant vectors, but also retains the advantage of halving the common-mode voltage amplitude in the traditional strategy, because this introduced vector is the basis vector for other sectors. In order to prevent the total vector action durations from overflowing and reasonably allocate the duration of each vector action, a corresponding neutral point voltage balance algorithm is designed, so that the neutral point voltage is effectively controlled, and the leakage current is greatly attenuated. Simulation results verify the effectiveness of the proposed improved modulation strategy.

TL;DR: A novel bypass capacitor solution is proposed to suppress leakage current in L-filter-based photovoltaic grid-connected inverters, effectively bypassing high-frequency common-mode voltage and reducing parasitic capacitor voltage, verified by experimental results.

TL;DR: In this paper, a flyback MPPT converter for PV-modules up to 100-150 W with galvanic decoupling of AC-grid and chopping the common mode currents by additional actively controlled circuitry is presented.

TL;DR: In this article, a dual active switched input buckboost inverter is proposed to provide continuous power in single-stage conversion even if one of the source has zero magnitude, and the buckboost converters in the circuit is operating in sequence with special PWM logic to create required AC output voltage.

TL;DR: In this paper, a topology study of the PV MICs in the power range below 500 W and covers most topologies recently proposed for MIC applications is presented, where the MIC topologies are classified into three different arrangements based on the dc link configurations.

TL;DR: In this article, the authors proposed a new high-efficiency topology that generates no varying common-mode voltage and requires the same low-input voltage as the bipolar PWM full bridge.

TL;DR: This paper will propose a single-phase transformerless inverter circuit being composed of the association of two step-down converters, which is possible to achieve a high level of efficiency and reliability.

TL;DR: An overview on developments and a summary of the state-of-the-art of inverter technology in Europe for single-phase grid-connected photovoltaic (PV) systems for power levels up to 5 kW is provided.