微电网带负荷并网的平滑切换条件及控制策略

以v/f孤岛控制方式的微电网为研究对象,建立了微电网模型,通过对微电网分别带恒功率负荷和恒阻抗负荷进行仿真分析,比较带不同类型负荷时对并网动态过程的影响大小.然后比较了压差、频差和角差对切换造成影响的大小,得出相角差在并网切换时对系统造成的影响要远远大于电压差和频率差对其造成的影响.频率差其次,电压差对并网造成的影响最小.最后提出了相应的控制策略,使微网根据大网调节自身的电压和频率,在合适的相位下进行并网,并通过仿真验证了所提策略的有效性.

Conditions and control strategies of microgrid connected with load smooth switchover

Taking v/f island control of microgrid as the object of study,this paper establishes the microgrid model,simulates separately the microgrid with constant power load and constant impedance load,and compares the influences of different types of load on paralleling dynamic process.By comparing the influences of voltage difference,frequency difference and angle difference on switchover,it proves that the influences of is more than that of voltage difference and frequency difference,frequency difference secondly and voltage least.At the end,the paper proposes relevant control strategy which enables microgrid to adjust its own voltage and frequency and to connect in the appropriate phase.Simulation proves the effectiveness of the strategy mentioned.