基于储能稳压的交直流混合电能路由器协调控制策略

将交/直/交级联变换器、直流变换器、储能及其变换器通过公共直流母线组合,构成含两个交流端口、三个直流端口的电能路由器拓扑结构。分析典型运行模式并提出储能稳压的交直流混合电能路由器虚拟同步机协调控制策略:在交流单/双端并网模式下,通过储能稳定直流电压,两端交/直、直/交变换器通过虚拟同步机功率外环控制功率流向及大小;在交流双端离网模式下,通过储能稳定直流电压的同时,配合分布式电源为交直流负荷供电。所提策略无需模式切换,降低了控制复杂性,可实现电能路由器各模式下直流电压稳定、就地消纳分布式发电,保证交直流负荷持续稳定供电,还可实现双端并网时电网馈线间的柔性互联、电网故障时潮流转供以及双端离网下的自稳定运行,有效提高了低压配电网的供电可靠性。最后,通过仿真和实验验证了所提协调控制策略的正确性和有效性。

Coordinated Control Strategy of AC/DC Hybrid Power Router Based on Voltage Stabilization by Energy Storage

AC/DC/AC converters, DC converters, energy storage and their converters are combined through a common DC bus to form the topology of power router which has two AC ports and three DC ports. Then, the typical operation modes are analyzed and the coordinated control strategy of AC/DC hybrid power router based on energy storage stabilizing voltage and virtual motor is proposed. Under the mode of single or double AC ports connecting to the grid, the power flow of two AC-DC converters are controlled by the power outer loop of virtual motor, while the DC voltage keeps steady due to energy storage. When both the AC ports are off-grid, not only keeps the DC voltage stable, but also supplies for AC and DC loads. The proposed strategy reduces the complexity of device control without mode switching. The stability of DC voltage is achieved in each operation mode, and the distributed generation is accommodated by local loads, and the constant and stable power supply for AC and DC load is ensured. Moreover, the flexible interconnection between the feeder lines of the distribution network is realized, and the power flows are transferred when the power grid fails, while the self-stable operation is realized when both the AC ports are off-grid, which effectively improves the power supply reliability of the low-voltage distribution network. Finally, the correctness and effectiveness of the proposed coordinated control strategy are verified by simulation and experiments.