What is the use of the braking resistor on the frequency converter? How to choose the size

In the process of rapid motor stop, due to inertia, a large amount of regenerative electric energy will be generated, which will directly act on the middle DC part of the inverter. If this part of electric energy is not consumed, the frequency converter will fail or be damaged. The braking resistor is used to consume this part of electric energy.

Each inverter has a braking unit (low power is braking resistor, high power is high power transistor GTR and its driving circuit), low power is built-in and high power is external.

The braking resistor must be selected according to the specifications of the frequency converter.

Extended data:

Frequency converter classification

1. Classification by input voltage level

Inverter can be divided into low-voltage inverter and high-voltage inverter according to the input voltage level. Common low-voltage inverters in China include single-phase 220 V inverter, three-phase 220 V inverter and I-phase 380 V inverter. High-voltage converters generally have 6 kV and 10 kV transformers, and the control mode is generally changed by high-low frequency converters or high-low frequency converters. ?

2. Classification by frequency conversion method.

Frequency converters are divided into AC-AC frequency converters and AC -DC frequency converters according to frequency conversion modes. AC-AC converter can directly convert power frequency AC into AC with controllable frequency and voltage, so it is called direct inverter. The AC-DC-AC frequency converter first converts power frequency alternating current into direct current through a rectifier device.

Then the direct current is converted into alternating current with adjustable frequency and voltage, so it is also called indirect frequency converter. ?

3. According to the nature of DC power supply.

In AC -DC- AC converter, DC power supply is divided into voltage converter and current converter according to the process of converting main circuit power supply into DC power supply.

Baidu encyclopedia-frequency converter