三相四线制电网谐波电流检测ip-iq法的改进

Improved ip-iq harmonic current detection method applied in three-phase four-wire power system

为使三相四线制电网中谐波电流检测电路结构更为简单,响应速度更快,检测结果更为精确,基于瞬时无功功率理论,对传统谐波电流检测法进行改进.将锁相环PLL去掉,设定固定角速度构造正、余弦回路;提出新算法矩阵,改进ip-iq算法,去掉零序分量,使得三相四线制电网中电流正序分量的计算更为简便;将低通滤波器LPF换成陷波滤波器,利用其点阻滤波的特性,滤除工频电流,然后与含有谐波的原电流作差,快速、精确测得谐波电流.通过仿真,验证了改进后的ip-iq法检测电路更简单、响应更快、检测结果更精确.

To make the application of the harmonic current detection circuit structure to three-phase four-wire power system more simple ,the response faster and the test results more accu-rate ,the harmonic current detection method was improved on the basis of instantaneous reactive power theory .First ,we removed the phase-locked loop PLL ,and set a fixed angular velocity and structure of sine and cosine loop ;Second ,we improved the algorithm by proposing a new algorithm to remove the zero-sequence component , making the calculations of current positive sequence component in three-phase four-wire power system easier ;Finally ,we replaced the low-pass filter LPF with notch filter ,filtered the current of 50 Hz frequence out using its point stop filter characteristics ,then compared with the current with harmonic arrent ,measuring the harmonic current quickly and accurately .The simulation proved that the improved detection method made the circuit simpler ,response faster and the test results more accurate .