Decoupling Power Balancing Strategy With Reduced Current Sensors for Two-Phase Interleaved Neutral Point Clamped DC/DC Converter Applied in Energy Storage System

This paper proposes a decoupling power balancing strategy with reduced current sensors for the two phase interleaved neutral point clamped DC/DC converter (NPCDC) applied in energy storage system (ESS). With the analysis of the NPCDC operation principle, an equivalent two voltage level analysis method is derived. On this basis, the power balancing strategy based on the total current time-sharing sampling method is proposed. Compared with the traditional strategy, the proposed strategy only requires two current sensors, reducing the number of current sensors by half. Meanwhile, the power balancing control is decoupled with output voltage control and capacitor voltage balancing control, which is helpful to simply the controller design. The small signal model of the proposed strategy based on the equivalent two voltage level analysis method is studied, and the controller design method is also presented in the paper. At last, the effectiveness of the proposed strategy is verified through an energy storage experimental platform, and the experimental results are presented and discussed.