There are techniques for detecting the motor current with a sensor that is placed in the DC portion of the inverter. Also, when using a DC current sensor, there is a case that current cannot be reproduced. These PWM techniques have been modified so that the detection rate of the motor current is improved. However, these PWM methods distort the motor current. In addition the acoustic noise of the motor is increased. In this paper, we theoretically explain the cause of the current distortion. The change of PWM generation causes distortion of current. We propose a PWM generation method using the three carriers. In addition, we also propose a method to reproduce the three-phase current from the DC current. We thus show that the proposed method improves the current detection rate without current distortion.
- Current sensor
- Power electronics
- Reproduce the three-phase current
- Shunt resistance