The electric drive system that controls motors has advantages such as significant energy-saving effects, simple maintenance, network-based centralized remote control, and the ability to form a control system with PLCs. The switching devices in the main circuit of the frequency converter generate harmonics during the process of switching circuits on and off. Lower-order harmonics usually have a greater impact on motor loads, causing torque pulsation; while higher-order harmonics increase the leakage current of the output cable of the frequency converter, resulting in insufficient motor output. Harmonic interference can also cause malfunction of relay protection devices, making electrical instrument measurements inaccurate, and even preventing normal operation. Using frequency converter speed regulation will produce noise and vibration because the output waveform contains high-order harmonic components. As the operating frequency changes, both the fundamental component and high-order harmonic components vary over a wide range, which may resonate with the inherent mechanical vibration frequency of the motor, and this resonance is the source of noise and vibration. During operation, the frequency converter generates heat due to internal losses, with the main circuit accounting for 98% and the control circuit about 2%. At the same time, in summer, the ambient temperature is too high, causing the temperature of the frequency converter to rise, which can reach 80 to 90°C. Since the frequency converter is an electronic device containing electronic components and electrolytic capacitors, excessive temperature can easily cause component failure, making the LCD screen unable to display data, and frequent protective actions of the frequency converter may occur. Therefore, it is necessary to suppress the harmonics output by the frequency converter within allowable limits, while also eliminating or reducing noise and vibration, and dissipating heat from the frequency converter to extend its service life. 1) Cut off the path of interference propagation through shared grounding wires. The grounding of power lines and control lines should be separated, that is, connect the grounding terminal of the power device to the ground wire, and connect the grounding terminal of the control device to the metal shell of the device panel. 2) Keep signal lines away from interference sources. Separating the wiring of current-carrying conductors is effective in eliminating this interference, that is, separate high-voltage cables, power cables, control cables from instrument cables and computer cables. 1) Increase the internal impedance of the power supply for the frequency converter. Usually, the internal impedance of the power supply equipment can buffer the reactive power of the DC filter capacitor of the frequency converter. The larger the internal impedance, the smaller the harmonic content. This internal impedance is the short-circuit impedance of the transformer. When selecting the power supply for the frequency converter, it is best to choose a transformer with large short-circuit impedance. 2) Install filters. Add an LC-type passive filter before the frequency converter to filter out high-order harmonics, usually filtering out the 5th and 7th harmonics. 4) Set up active filters. Active filtering automatically generates a current with the same amplitude and exactly opposite phase as the harmonic current, thereby effectively absorbing harmonic currents. 1) When the low-order harmonic components in the output of the frequency converter resonate with the rotor's inherent mechanical frequency, the noise increases; when the high-order harmonic components in the output resonate near the natural frequencies of the iron core, casing, bearing bracket, etc., the noise also increases. The noise generated by the motor driven by the frequency converter, especially harsh noise, is related to the switching frequency of PWM control, AC power frequency withstand voltage test especially in the low-frequency range. To solve this problem, generally connect an AC reactor on the output side of the frequency converter. If there is a margin in electromagnetic torque, the u/f setting can be reduced to suppress and lower the noise. 2) When the frequency converter is working, the magnetic field caused by high-order harmonics in the output waveform exerts electromagnetic driving forces on many mechanical components. When the frequency of these driving forces is close to or coincides with the natural frequencies of these mechanical components, resonance will occur. The main impact on vibration is from lower-order harmonic components, which have a greater influence in PAM mode and square wave PWM mode. However, when SPWM mode is adopted, the low-order harmonic components are small, and the impact is also reduced. The method to reduce or eliminate vibration is to connect an AC reactor on the output side of the frequency converter to absorb the high-order harmonic current components in the output current. When using frequency converters with PAM mode or square wave PWM mode, they can be changed to SPWM mode frequency converters to reduce pulsating torque, thereby weakening or eliminating vibration and preventing mechanical parts from being damaged due to vibration. The operating environment temperature for general-purpose frequency converters is generally required to be -10°C to +50°C. To ensure reliable operation of the frequency converter, power frequency resonance overvoltage and extend its service life, heat dissipation must be carried out for the frequency converter. In winter, the built-in fan of the frequency converter can be used to dissipate the heat inside the converter cabinet; in summer, when the temperature itself is 40°C, the internal heat dissipated by the built-in fan can only raise the indoor and converter cabinet temperature. At this time, the best way is to use windows or evenly and appropriately drill several holes of 500mm ($393.6600) on the walls above and below the converter cabinet in the machine distribution room, while ensuring that there is some space around the frequency converter inside the control cabinet to maintain good natural ventilation. AC withstand voltage test principle If this is still not enough, you can turn on the fan, or install exhaust fans and air ducts at the holes to forcibly extract the heat generated by the frequency converter outdoors. Finally, consider using air conditioning to forcibly cool the space environment where the frequency converter is installed. It is very necessary to strengthen research on fault problems in frequency converter applications, which is of great significance for the normal use of frequency converters, tapping potential and increasing efficiency.