Main fault causes and preventive measures of the inverter - Solutions - Huaqiang Electronic Network

Filter 18.432M

1. External electromagnetic induction interference If there is interference source around the inverter, they will invade the inverter through the radiation or power line, causing the control circuit to malfunction, resulting in abnormal operation or shutdown, and even damage the inverter in severe cases. It is important to improve the anti-interference ability of the inverter itself. However, due to the limitation of the cost of the device, it is more reasonable and necessary to eliminate the interference source by taking noise suppression measures on the outside. The following measures are specific methods for implementing the “three noes” principle for noise interference: all the relays around the inverter and the control coil of the contactor need to be equipped with absorption devices to prevent the surge voltage, such as RC absorbers; Wiring distance and separation from the main line; the specified shielded circuit should be carried out according to the regulations. If the line is long, a reasonable relay method should be adopted; the grounding terminal of the inverter should be carried out according to the regulations, not the same as electric welding and power. Grounding is mixed; a noise filter is installed at the input of the inverter to avoid interference introduced by the power supply line.
2. Installation environment The inverter belongs to the electronic device device, and has detailed requirements for installation and use environment in its specification. In special cases, if these requirements are not met, the corresponding suppression measures must be adopted as much as possible: vibration is the main cause of mechanical damage to electronic devices. For vibration shocks, vibration and other vibration-proof measures should be used; moisture and corrosion Gas and dust will cause rust, poor contact, and low insulation of the electronic device to form a short circuit. As a precautionary measure, the control board should be treated with anti-corrosion and dustproof, and a closed structure; temperature is the life and reliability of the electronic device. Important factors, especially semiconductor devices, install air conditioners or avoid direct sunlight depending on the environmental conditions required by the device.
In addition to the above three points, it is also necessary to regularly check the air filter and cooling fan of the inverter. For special high-cold occasions, in order to prevent the microprocessor from working properly due to low temperature, necessary measures such as setting a space heater should be taken.
3, power supply abnormal power supply abnormal performance in various forms, but roughly divided into the following three types, that is, phase loss, low voltage, power outage, and sometimes their mixed form. Most of the main causes of these anomalies are caused by wind, snow, and lightning strikes, and sometimes due to short-circuit to ground and phase-to-phase short circuit in the same power supply system. Lightning strikes vary greatly by region and season. In addition to voltage fluctuations, some power grids or self-generating units also have frequency fluctuations, and these phenomena sometimes appear repeatedly in a short period of time. In order to ensure the normal operation of the equipment, the power supply of the inverter is also required.
1) If there is a direct start motor and induction cooker nearby, in order to prevent the voltage drop caused by the input of these devices, it should be separated from the inverter power supply system to reduce the mutual influence;
2) For those occasions that can continue to operate after the instantaneous power failure, in addition to selecting the inverter of the appropriate price, the ratio of the speed reduction of the load motor is also considered in advance. The inverter and the external control loop adopt the instantaneous stop compensation mode. When the voltage is restored, the overcurrent in the acceleration is prevented by the speed tracking and the detection of the speed measuring motor;
3) For equipment that requires a required amount of operation, an automatic uninterruptible power supply unit with automatic switching is required.
The diode input and the inverter using the single-phase control power supply can continue to work in the phase loss state, but the current of the individual components of the rectifier is too large and the pulse current of the capacitor is too large. If the long-term operation will cause the life and reliability of the inverter. Adverse effects should be checked and dealt with as soon as possible.
4. The impact voltage formed by lightning strikes, inductive lightning strikes or induced lightning strikes can sometimes cause damage to the inverter. In addition, when the vacuum circuit breaker is provided on the primary side of the power supply system, the open circuit breaker can also generate a high surge voltage. When the primary side vacuum circuit breaker is disconnected, a high voltage surge spike is formed on the secondary side by coupling. In order to prevent overvoltage damage caused by the surge voltage, it is usually necessary to apply a absorbing device such as a varistor at the input end of the inverter to ensure that the input voltage is not higher than the maximum voltage allowed during the main circuit of the inverter. When a vacuum circuit breaker is used, An additional RC surge absorber should be formed by impact as much as possible. If there is a vacuum circuit breaker on the primary side of the transformer, the inverter will be disconnected before the vacuum circuit breaker is operated in the control timing.