Filter 18.432M

1, the heat dissipation problem of the inverter

The fault rate of the inverter rises exponentially with the increase of temperature, and the service life decreases exponentially with the increase of temperature. The ambient temperature rises by 10 °C, and the service life of the inverter is halved. Proper use of the frequency converter must be carefully considered.

2. Interference and damage caused by the inverter

Non-linear rectifying devices such as thyristors or rectifier diodes are commonly used in frequency converters. The harmonics generated by them will cause interference to the power grid, causing voltage distortion of the power grid, affecting the power quality of the power grid. Higher harmonics will also cause copper loss in the stator of the motor. The increase in iron consumption.

The output part of the inverter is generally a switching device such as IGBT, which will generate strong radiation interference on the output line while outputting energy, which affects the normal operation of the surrounding electrical equipment. From the foreign standards of harmonics, the distortion rate of single voltage is 3%-6%, and the distortion rate of total voltage is acceptable in the range of 5%-8%.

3. Measures taken in response to the above problems

(1) Method for reducing the ambient temperature around the inverter

The inverter is usually installed in the control cabinet. If it is equipped with a reactor or a braking resistor, it is better to isolate it from the inverter. It is better to install it above or above the inverter.

(2) Install a cooling fan in the control cabinet

4. Method for reducing or weakening the harmonics of the inverter and electromagnetic radiation interference

In order to reduce the influence of inverter harmonics on other equipment, AC/DC reactors, multi-phase pulse rectifiers and filters can be used in the input and output of the inverter to reduce the THDV in the incoming line, and in the power equipment system. Common methods are usually the following.

(1), using an isolation transformer

The isolation transformer with isolation layer can block most of the conducted interference before the isolator, and can also have the function of power supply voltage conversion. The isolation transformer is often used in the control system, plc and other low voltage and low power. Anti-interference of electrical equipment.

(2), using filter modules or components

At present, there are many filter modules or components specially used for anti-interference. These filters have strong anti-interference ability, and also prevent the anti-interference of the electric appliance itself from being transmitted to the power supply, and some also have a spike voltage absorption function. There are many benefits to various types of electrical equipment.