One of the setting parameters of 1. inverter is the carrier frequency, that is, the low-frequency voltage required by the motor is sent by the carrier, and the output is PWM pulse voltage. For example, the carrier frequency is 10KHz, and the output is a square wave pulse with the frequency of 10KHz.
2. In addition to the fundamental frequency, the square wave pulse has a very rich frequency spectrum, and there are many higher harmonics, including (2, 3, 4,. . . . N- 1, n)A, where a is the fundamental frequency. If the fundamental wave according to the first point is 10KHZ, then its frequency spectrum includes 20, 30, 40,. . . . . (n- 1) 10, 10 khz, but the energy distribution is uneven. Except for the maximum energy of the fundamental wave, the energy distribution of the higher harmonics is very uneven, and the maximum energy is concentrated in the higher harmonics below the fifth harmonic. But the higher the frequency, the greater the influence of RF interference.
That's how the interference of the inverter comes from. There is interference, that's for sure.