Braking unit provider: In the operation of industrial machinery, rapid braking is often required. The mechanical energy (kinetic and potential energy) on the motor shaft is converted into regenerative electrical energy through the motor. The capacitors in the middle of the frequency converter cannot store it within the specified voltage range, or the internal braking resistance cannot be consumed in time, which feeds back to the DC bus terminal of the frequency converter, resulting in overvoltage in the DC part of the frequency converter.
At this time, an external (or built-in) frequency converter specific braking unit and frequency converter specific braking resistor are needed to accelerate the consumption of regenerative energy, ensure the realization of the fast braking requirements of the working machinery, and protect the frequency converter from the interference of this regenerative energy and overvoltage phenomena.
Principle of braking unit: The braking unit is composed of a high-power transistor GTR and its driving circuit. Its function is to provide a pathway for the discharge current IB to flow. When the working machinery requires rapid braking, and within the required time, the regenerative energy of the frequency converter cannot be stored in the intermediate capacitor within the specified voltage range or the internal braking resistor cannot consume it in time, causing overvoltage in the DC part, an external braking component needs to be added to accelerate the consumption of regenerative energy.
Principle of braking resistance: During the process of decreasing operating frequency, the electric motor will be in a regenerative braking state, and the kinetic energy of the driving system will be fed back to the DC circuit, causing the DC voltage UD to continuously rise and even reach a dangerous level. Therefore, it is necessary to consume the energy regenerated into the DC circuit to keep UD within the allowable range. The braking resistor is used to consume this energy.
Braking unit+resistor: During the process of decreasing operating frequency, the motor will be in a regenerative braking state, and the kinetic energy of the driving system will be fed back to the DC circuit, causing the DC voltage UD to continuously rise and even reach a dangerous level. Therefore, it is necessary to consume the energy regenerated into the DC circuit to keep UD within the allowable range. The braking resistor is used to consume this energy. The braking unit is composed of a high-power transistor GTR and its driving circuit. Its function is to provide a pathway for the discharge current IB to flow through the braking resistor.