General Type of Frequency Inverter

 In variable frequency speed regulation system, slow down and stop of the motor are achieved by gradually reduce the frequency. In reduce the frequency moment, the motor synchronous speed decline, while because of mechanical inertia, the motor rotor speed is not changed, when the synchronous speed is less than the rotor speed, rotor current phase change almost 180 °, the motor turn into generation condition, and the motor shaft on the braking torque of the motor in the regenerative braking state, renewable energy make the capacitor charge accumulation for a short period of time, and form pump up voltage apply DC bus voltage rise. Over high DC bus voltage can make the part of the device damaged, therefore, it must use the brake unit (braking resistor) consumption of renewable energy, otherwise the inverter will jump over voltage protection or malfunction.