光伏并网逆变器模型预测直接功率控制方法研究

A Model Predictive Direct Power Control Method for Photovoltaic Grid-Connected Inverter

根据瞬时功率理论,建立了光伏并网逆变器在旋转dq坐标系下的功率预测模型。采样并网电压、电流后,利用该模型能够直接预测出并网输出的有功功率和无功功率。然后,利用模型预测控制方法,选用预测功率与给定功率误差的绝对值之和作为价值函数,根据功率预测模型,选择最优空间电压矢量,设计了光伏并网逆变器的模型预测直接功率控制策略。该控制策略无需使用PWM调制模块和内环电流控制,计算量小,易于实现。在光照强度稳定、变化等条件下,对控制系统的性能进行了仿真。结果表明,并网逆变器能够跟踪光照变化快速输出有功、无功功率,具有较好的动、静态性能,验证了所提出的控制策略的有效性。

Based on the instantaneous power theory,power predictive model of photovoltaic grid connected inverter in dq rotating coordinates is established.The output active power and reactive power of the grid-connected can be directly predicted by using the predictive model.The model predictive direct power control strategy of photovoltaic grid connected inverter is designed.According to the power predictive model and cost function,the optimal space voltage vector is selected.The proposed control strategy does not need PWM modulation module and the inner current control.It has low computational complexity and is easy to be implemented.The control system performance is simulated in different light intensity conditions.The simulation results show that the grid-connected inverter can track illumination change and output power with good dynamic and static performance,which validate the effectiveness of proposed control strategy.