The braking resistor has the same effect as the power generation, which can prevent the inverter from overvoltage during deceleration, reduce the deceleration distance, and improve dynamic performance.
The braking resistor is a type of ripple resistor. It is mainly used in the mechanical system where the inverter controls the motor to stop quickly to help the motor convert the regenerated electric energy generated by the motor into heat energy.
Principle of braking resistor: When the operating frequency decreases, the motor will be in a regenerative braking state, and the kinetic energy of the drag system will be fed back to the DC circuit, causing the DC voltage UD to continue to rise, and may even reach dangerous levels. the point. Therefore, the energy regenerated into the DC circuit must be dissipated to keep the UD within the allowable range. The braking resistor is used to consume this energy.
Brake unit + resistor: The braking unit is composed of a high-power transistor GTR and its drive circuit. Its function is to provide a path for the discharge current IB to flow through the braking resistor.
Extended information:
The braking resistor usage rate specifies the usage efficiency of the braking resistor to avoid overheating and damage of the braking resistor, which will affect the braking effect of the braking unit . The lower the usage rate of the braking resistor is set, the smaller the degree of heating of the resistor, the less energy consumed on the resistor, and the worse the braking effect. At the same time, the capacity of the braking unit is not fully utilized.
Theoretically, when the braking resistor utilization rate is 100%, the braking unit capacity is fully utilized and the braking effect is the most obvious. However, this requires a larger braking resistor power. , users should consider it comprehensively. Under the premise that the resistance and power of the braking resistor have been determined, for large inertia loads that decelerate slowly, choosing a lower resistor usage rate will achieve better results.
For loads that need to stop quickly, a larger braking resistor usage rate should be selected.
Baidu Encyclopedia—Brake Resistor