【摘要】 针对三相光伏并网逆变器的特点,设计了一种新的无差拍功率控制策略。详细推导了三相并网逆变器的离散数学模型,提出了基于瞬时有功、无功功率无差拍控制的方法。采取功率控制的方法,省去了传统无差拍电流控制方法所需的预测环节,简化了控制系统;在电网电压相角检测方面借助虚拟磁链的低通滤波特性克服谐波影响,保证角度计算的准确性;引入定频SVPWM模块取代了传统直接功率控制中的滞环比较器和开关表,弥补了传统方法开关频率不固定,容易产生谐波的劣势,提高了三相并网逆变器的性能。通过在Matlab/Simulink软件平台下的仿真证明了控制方法的有效性。更多还原

【Abstract】 A novel deadbeat direct power control method was presented according to the characteristic of three-phase grid-connected photovoltaic inverters.In order to analyze deadbeat control in detail,the stringent discrete-time mathematic model of three-phase grid-connected inverters was deduced.The predication part was omitted in the proposed control strategy because the instantaneous power was calculated in d-q coordinates,which simplified the controlling unit.Virtual flux was used to avoid the influence of harmonic component and ensure the accuracy of the angel calculation.The active power and reactive power could be regulated respectively with constant switching frequency since the SVPWM module was considered rather than hysteresis and switching table in this paper,and with less distortion of output current,compared to traditional direct power control,which improve the performance of three-phase grid-connected inverters.The feasibility and correctness of the control strategy was verified in Matlab/Simulink finally.更多还原