混合母线微电网的功率平衡控制策略

Power balance control strategy of hybrid-bus microgrid

为提高微电网在模式切换等暂态条件下的动态响应性能,提出一种基于交直流混合母线拓扑的微电网功率平衡控制策略。将直流母线和交流母线分别作为瞬态和稳态的两级功率平衡点,使分布式电源组群与储能装置经直流母线相结合进行联合供电。在暂态条件下,通过稳定直流母线电压迅速地匹配供需双方的功率,相应地调整逆变控制策略来稳定系统电压、频率及调节电能质量。仿真结果表明:在微电网运行模式切换和受扰动时,该方法均能使微电网实时满足负载的功率需求;电压幅值和频率稳定在额定值,相对误差小于1%;电能质量符合国家标准,总畸变率(THD)小于2%;电压和功率参数响应时间仅为0.02 s左右。

In order to improve the dynamic performance of the micro-grid in transient conditions such as mode switching, a new topology of hybrid-bus micro-grid and its corresponding power balance control strategy were proposed. The bus of the DC side and the AC side were regarded respectively as two level power balance points so that the distributed power group combines with energy storage devices to supply the power via the DC bus. In transient conditions, by stabilizing the DC voltage, the power of supply-side and demand-side was matched quickly. Accordingly, the control strategy of inverter was adjusted to stabilize voltage, and frequency of the system and to adjust power quality. The results of simulation show that the control strategy ensures that the micro-grid meets the power demand of loads quickly when the mode is switched or disturbed. The amplitude and frequency of voltage are maintained at rated values so that the error is less than 1%. The power quality achieves the national standard. The total harmonic distortion （THD） is less than 2% and the response time of parameters of voltage and power is only about 0.02 s.