Accurate and Fast Harmonic Detection Based on the Generalized Trigonometric Function Delayed Signal Cancellation

The abundant grid-connected power electronic devices and non-linear loads used widely have caused power system harmonic pollution. Harmonic detection is very important for selective harmonic compensation used to improve the power quality. To detect the individual harmonic component accurately and fast, a harmonic extraction based on generalized trigonometric function delayed signal cancellation (GTFDSC) is proposed to extract the fundamental component or the desired harmonic component. The proposed GTFDSC can be used to accurately extract the desired harmonic component under various harmonic scenarios because of its excellent filtering capability. What's more, the parameters of the GTFDSC can be flexibly designed according to the distribution of the harmonic series of the input signal, thereby reducing the delay time and the number of operators. Furthermore, the GTFDSC is self-adjustable to fundamental frequency deviations by introducing the frequency feedback loop, and it is able to achieve excellent filtering capability and fast dynamic performances. Lastly, the experimental results are provided to verify the effectiveness of the proposed method.