Protect the inverter

During the fast stop of the motor, due to inertia, a large amount of regenerative power will be generated. If this part of the regenerative power is not consumed in time, it will directly act on the DC circuit part of the inverter. In the lighter case, the inverter will report a fault. Otherwise, it will damage the inverter; the emergence of the braking resistor solves this problem and protects the inverter from the harm of the motor's regenerative electric energy.

Guaranteed power supply network

The braking resistor directly converts the regenerative electric energy during the rapid braking process of the motor into heat energy, so that the regenerative electric energy will not be fed back to the power supply network and will not cause voltage fluctuations in the power grid, thus ensuring the smooth operation of the power supply network.

Resistance selection

The selection of braking resistor is limited by the maximum allowable current of the inverter-specific energy-consumption braking unit, and there is no clear correspondence with the braking unit. Its resistance is mainly selected according to the required braking torque. The power is determined according to the resistance value and usage rate of the resistor. There is an inviolable principle in the selection of the resistance of the braking resistor: it should be ensured that the current IC flowing through the braking resistor is less than the maximum allowable current output capacity of the braking unit, namely: R>800/Ic. Among them: 800-the maximum DC voltage that may appear on the DC side of the inverter. Ic——The maximum allowable current of the braking unit. In order to make full use of the capacity of the selected inverter-specific braking unit, it is usually the most economical to select the braking resistance value close to the minimum value calculated by the above formula, and at the same time, the maximum braking torque can be obtained. However, this requires Larger braking resistor power. In some cases, a large braking torque is not required. At this time, it is more economical to choose a larger braking resistor resistance value, which can reduce the power of the braking resistor, thereby reducing the purchase of brakes. The cost of the resistance is that the capacity of the braking unit is not fully utilized.