级联式储能系统中电池自均衡控制策略研究

Research on Battery Self-Balancing Control Strategy in Cascade Energy Storage System

针对独立电池供电的组合级联式储能系统中电池SOC不均衡问题,基于特征谐波消除PWM方法提出了一种新的差异化充放电控制策略。当检测到各电池SOC不均衡时,采用差异化充放电控制使各电池SOC趋于一致;当电池SOC达到均衡时,切换到同步充放电的移相SPWM控制。该方法提高了整个组合级联式储能系统的可用率和储能系统的有效容量,改善了储能系统的电能质量。文中推导了差异化充放电控制方法的原理,给出了切换条件。在PSCAD/EMTDC中建立了组合级联式储能系统模型,验证所提出的电池自均衡控制策略的有效性。

In terms of the imbalance problems of the state of charge of batteries in independent battery powered hybrid cascade energy storage system, this paper proposes a new control strategy, the difference charge or discharge, which based on Selective Harmonic Elimination PWM.When the state of charge of batteries is imbalanced, carry on difference charge or discharge to adjust the state of charge of batteries convergence.If balanced,transfer to the synchronous charge or discharge by using phase shift SPWM.As a result, it improves the whole hybrid cascade storage system availability and capacity and prolongs the batteries＇ service life even that of the whole system. This paper derives the principle of difference charge or discharge control method and puts forward the switching condition.Its reasonable and feasibility are verified by an example of hybrid cascade energy storage system, from theoretical analyses in conjunction with model investigations established in PSCAD/EMTDC.