Test method: exit the filter and then measure the harmonic content can be concluded.
Solution: Even harmonics are difficult and costly to manage, so it is recommended that you redesign the values of the filter channels and modify the original filter. This should be the most economical solution.
Second Harmonics
The root cause of harmonics is due to nonlinear loads. When the current flows through the load, it is not linearly related to the applied voltage, forming a non-sinusoidal current, which generates harmonics. Harmonic frequency is an integer multiple of the fundamental frequency, according to the French mathematician Fourier (M. Fourier) analytical principle proves that any repetitive waveform can be decomposed into a series of harmonics containing the fundamental frequency and a series of multiples of the fundamental sinusoidal component. Harmonics are sinusoids, each with a different frequency, amplitude and phase angle. Harmonics can be I distinguished as even and odd in nature, with the 3rd, 5th, and 7th numbered odd harmonics and the 2nd, 4th, 6th, 8th, etc., even harmonics, e.g., when the fundamental is 50 Hz, the 2nd harmonic is lOOHz, and the 3rd harmonic is 150 Hz.