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To solve the bidirectional power control issue under wide range voltage changes on both sides of the dc bus and energy storage battery in the dc energy storage system, this article proposes a multiobjective decoupling model predictive control (MPC) (MOD-MPC) strategy for the three-level noninverting Buck–Boost converter (TLNBC). The mathematical model of TLNBC based on the voltage difference of split capacitors is first studied, solving the problem of multi branch modeling of split capacitor voltage. On this basis, a MOD-MPC power control strategy with dual-carrier modulation method is proposed by analyzing the relationship between system current and split capacitor voltage sharing control. The optimal control variables solution is directly obtained by solving the cost function, achieving independent control of system current and split capacitor voltage sharing, and greatly reducing computational load. The decoupling MPC controlled TLNBC can operate in Buck and Boost modes when energy is transmitted in any direction catering to various scenarios while exhibiting favorable control performance. The effectiveness of the converter and control strategy is verified through experiments.

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.