Provide improved overload protection for power supply
Reduce the current harmonic distortion of inverter
Increase the power factor of input supply, reduce high order harmonics
Restrain the surge to power equipment caused by transformer

To restrict the capacitive charging current of the cable connecting inverter and motor.
Deactivate the voltage rising rate of inverter output PWM wave.
Compensate capacitor charging current in case of long cable.
Reduce leakage current of motor grounding.