低电压穿越(Low-voltage ride through,LVRT)是影响光伏并网发电系统稳定运行的重要因素。针对这一现状,本文提出了一种混合储能(hybrid energy storage system,HESS)的控制策略来解决。HESS由蓄电池储能系统(battery energy storage system,BESS)和超导磁储能系统 (Superconducting Magnetic Energy Storage,SMES) 构成。采用低通滤波的方法将不平衡功率分频给HESS分配功率指令。当光伏并网发电系统稳定运行时,光伏逆变器采用PQ控制以最大程度消纳新能源,BESS负责处理低频波动的功率,SMES负责处理高频波动的功率。当出现短路故障时,逆变器采用无功电流注入的策略使逆变器发出无功,此时仅由SMES吸收不平衡功率,BESS不参与运行。MATLAB仿真验证了所提出的控制策略有效性。
英文摘要:
Low-voltage ride through (LVRT) is an important factor affecting the stable operation of photovoltaic grid connected power generation system. In view of this situation, a hybrid energy storage system (HESS) control strategy was proposed to solve this problem in this paper. HESS consists of battery energy storage system (BESS) and superconducting magnetic energy storage (SMES). The unbalanced power is divided into frequency by using low-pass filter, and the power command is assigned to the HESS. When the photovoltaic grid connected power generation system operates stably, PQ control strategy is adopted for photovoltaic inverter to maximize consumptiveStheseSrenewableSenergies, BESS is responsible for handling the power with low-frequency fluctuation, and SMES is responsible for handling the power with high-frequency fluctuation. In case of short-circuit fault, the inverter adopts the strategy of reactive current injection to make the inverter generate reactive power. During the LVRT, the unbalanced power is absorbed only by SMES, and BESS does not participate in the operation. The effectiveness of the proposed control strategy is verified by MATLAB simulation.