AC Drives (Industrial Inverters, VVVF Inverter, Variable Frequency Drives) are devices for controlling motor speed by converting DC to AC(Industrial Inverters, VVVF Inverter, Variable Frequency Drives). The emergence of AC Drives (Industrial Inverters, VVVF Inverter, Variable Frequency Drives) has improved productivity spectacularly and made a huge contribution to the development of the industry. Further, AC Drives (Industrial Inverters, VVVF Inverter, Variable Frequency Drives) have brought about a substantial change to our lives. For example, air flow from air-conditioners and fans can be regulated by changing motor speed. Thanks to AC Drives (Industrial Inverters, VVVF Inverter), we can keep a room at a comfortable temperature even in the hot summer and cold winter. The regulated airflow also reduces energy consumption, contributing to energy conservation