3 3 3 METHOD AND APPARATUS FOR MEASURING AVERAGE CURRENT OF 3 PHASE MOTOR BASED ON CURRENT MEASUREMENT OF PWM ON-DUTY PERIOD

摘要

According to an embodiment of the present invention, a voltage measurement circuit measuring a voltage on both ends of a dividing resistor to measure a current flowing on a three-phase motor includes: an edge extracting unit which detects the rising and falling edges of pulse width modulation (PWM) signals for controlling the three-phase motor to output rising and falling edge detection signals; a sample and holding circuit which samples the voltage on both ends of the dividing resistor when detecting edges based on the rising and falling edge detection signals; and a low frequency band pass filter which receives signals output from the sample and holding circuit to pass the low frequency band of output signals of the sample and holding circuit. According to the present invention, the voltage measurement circuit can significantly reduce the resource loads on a microcontroller unit (MCU) compared to a conventional three-phase motor control system executing an analog-digital conversion (ADC) trigger module as a separate software module and utilize the save MCU resources for a control operation for vehicle safety, thereby significantly contributing to vehicle safety.