# Principle of inverter braking resistor_function of inverter braking resistor

What is inverter braking resistor

When the motor or other inductive load driven by the inverter is stopped, it is generally realized by the way of energy-consumption braking, that is, the kinetic energy of the motor and the magnetic energy in the coil after the stop are consumed by another energy-consuming component. , So as to achieve fast parking. When the power supply is stopped, the inverter circuit of the inverter is reversely conducted, and the remaining electric energy is fed back to the DC bus of the inverter. The voltage on the DC bus will rise accordingly. When it reaches a certain value, the inverter The braking resistor of the converter is put into operation, so that this part of the electric energy is consumed by the way of resistance heating, while maintaining the voltage on the DC bus at a normal value.

Principle of inverter braking resistor

When the servo motor is braking, the servo motor is in the state of generating electricity. This means that energy will be returned to the DC bus of the servo drive. Because the DC bus contains capacitors, the DC bus voltage will rise. The amount of voltage increase depends on the kinetic energy of the motor and the capacity of the capacitor on the DC bus when braking is started. If the braking kinetic energy is greater than the capacitance on the DC bus, and there is no other drive on the DC bus to accommodate the energy, the drive will consume the energy through the braking resistor or feed it back to the power supply.

Inverter braking resistor function

When the motor decelerates, the excessive equipment inertia will turn the motor into a generator. This is due to the power generation running state, and the motor supplies power to the inverter in the reverse direction, which will cause an overvoltage alarm of the inverter. In order to release this part of the energy, use the method of increasing the resistance power (appropriately reducing the resistance value). There is also a reverse power supply to the power circuit, which is more used in the frequency conversion system of the common DC bus, which can save energy. The braking resistor and the power generation effect are the same, which can prevent the inverter from decelerating and overvoltage, reduce the deceleration distance, and improve the dynamic performance.

The built-in brake of the motor is generally used for the final parking brake instead of the deceleration brake. This is essentially different from the resistance brake, because the resistance brake only works during the deceleration of the motor, and has no effect after the motor stops. Yes, the brake must be used to keep the motor stationary (with potential energy load).