[ Abstract ] This paper analyzes the harmonic generation mechanism, harmonic interference path, harmonic interference's hazard to electrical equipment, and commonly used methods for suppressing harmonic interference in frequency converters. [ Keywords ] Frequency converter; interference; prevention and control methods In recent years, due to the need for speed regulation and energy saving, frequency conversion speed regulation technology has been used in more and more occasions. The core part of it, the frequency converter, is a power electronic device containing electronic components and computer chips, which is susceptible to external electrical interference. Because the frequency converter performs high-power diode rectification and high-power transistor inversion, high-order harmonics of the current are generated in the input and output circuits, interfering with the power supply system, load, and other nearby electrical equipment. In actual use, frequency converter harmonic interference problems are frequently encountered. The following is a brief introduction to the harmonic generation mechanism, interference path, hazard, and effective methods for suppressing interference in frequency converters. 1 Harmonic Generation Mechanism of Frequency Converters Harmonic generation mechanism on the input side of the frequency converter: Not limited to general-purpose frequency converters, DC motors powered by thyristors, motors without commutators, etc., any device with a rectifier circuit on the power supply side will generate harmonics due to its nonlinearity. In a three-phase bridge rectifier circuit, the input current waveform is a rectangular wave. The waveform is decomposed into a fundamental wave and various harmonics according to Fourier series, typically containing 6n+1 (n=1, 2, 3…) harmonics. These higher-order harmonics will interfere with the input power supply system. The mechanism of harmonic generation on the inverter input side: Currently, most inverters use PWM or SPWM modulation AC/DC conversion methods. The voltage and current on the inverter output side are not sinusoidal or not perfectly sinusoidal, also containing abundant harmonics, which also affect the output circuit. That is to say, after the inverter is put into operation, it will generate higher-order harmonics that interfere with the connected power grid and electrical equipment. This is what is commonly referred to as electromagnetic compatibility (EMC). [b][align=center]For more details, please click: Inverter Harmonic Interference and Prevention[/align][/b]