【摘要】 在三相不对称情况下用d-q运算方式谐波检测方法检测电网谐波时,锁相环的锁相结果与电压正序分量之间的相差使检测结果存在系统误差。为了减小这个误差,经过理论分析,可用输出的与电压具有相同频率的对称性较好的基波电流取代输入电压形成一个闭环网络。仿真分析证明,这种方法可以较精确地检测出三相电压不对称情况下的基波和谐波电流,简化了电路。更多还原

【Abstract】 In unbalanced three-phase system,when using d-q calculating mode based harmonic current detecting method,there is a systematic error between the detected result and actual current arising by the phase difference of phase locking result and positive voltage component.To eliminate the error,the output current,which is more balanced and has the same frequency as the voltage,is used as the input of PLL.Thus the detecting system becomes a closed-loop system.Simulation result shows that the fundamental current and harmonic current can be measured more accurately than the traditional method and the circuit becomes simpler.更多还原