Research on the Hybrid Energy Storage System Using a Superconducting Coil and a Secondary Battery

高能量密度和高功率密度的储能装置有望从补偿波动负荷和不稳定分布式发电的角度出发，如风电机组、光伏电池等。SMES(超导磁储能)比其他储能方式具有更高的功率密度，二次电池比SMES具有更高的能量密度。提出了SMES和二次电池相结合的混合储能方式，研究了各储能装置功率参考值的分配方法，并进行了实验和仿真。1)为了系统的设计和评估，建立了二次电池和功率转换器的等效电路模型。2)为了实现超导线圈和二次电池之间的功率分配，研究了采用高通和低通滤波器的方法。因此，由于相位滞后较小，一阶高通和低通滤波器是首选。3)采用带滤波器的模糊控制方法，避免了超导线圈的能量饱和和耗尽，实现了对二次电池的功率控制。4)利用改进的控制方法和测量数据对高速铁路变电所和光伏发电的波动补偿进行了仿真。结果表明，两种情况下混合储能系统的效果都得到了验证。但对于高速铁路变电站，由于SMES补偿的频率范围内的波动功率较大，因此取得了较好的效果。

Energy storage devices with high energy density as well as high power density are expected to be developed from the point of view of compensation of fluctuating load and generated power by unstable distributed generations such as wind turbines, photovoltaic cells and so on. SMES (Superconducting Magnetic Energy Storage) has higher power density than other energy storage methods, and secondary batteries have higher energy density than SMES. The hybrid energy storage device using SMES and secondary batteries is proposed as the energy storage method with higher power and energy density, the sharing method of power reference value for each storage device has been studied, and experiments as will as simulations have been carried out. Obtained results are summarized as follows.1) For the design and evaluation of the system, equivalent circuit models for a secondary battery and power converter have been developed.2) For sharing power between a superconducting coil and a secondary battery, the method using high pass and low pass filters has been studied. As a result, the first-order high pass and low pass filters are preferred due to smaller phase lag. Higher-order filters showed worse results due to phase lag of the filters.3) Using the method using fuzzy control with filter mentioned above, saturation and exhaustion of energy of superconducting coil have been avoided and power control of the secondary battery can be carried out4) Simulations of compensation of fluctuation from high speed railway substation and photo voltaic generation have been carried out by using developed control method and data from measurements. As a result, the effect of hybrid energy storage system has been verified for both cases. But the better result was obtained for the high speed railway substation, because of the higher fluctuating power at the frequency range compensated by SMES.