[L1] 1 Overview [L2] 1) Electrical Definition [L4] - A device that performs the role of reverse conversion, such as converting Direct Current (DC) to Alternating Current (AC). [L5] * DC → AC Conversion : Reverse Conversion ▶ Inverter [L5] * AC → DC Conversion : Forward Conversion ▶ Converter [L2] 2) Industrial Definition [L4] - An inverter is a device that changes the rotational speed of a motor by changing the frequency. [L4] - Applied to pump motors, coolers, crane trolley drive units, etc. [L2] 3) Operation Principle [L4] - AC can be obtained by continuously switching DC on and off (intermittent). [L4] - A speed control device for AC motors can be made using the inverter conversion method. [L5] * Has structural features of being simple and easy to maintain. [L2] 4) Inverter Rotation Speed [L4] - For AC motors, the following relationship holds between rotation speed, number of motor poles, and frequency. [L5] * N = 120 X f / P X (1-s) [L5] (N: Rotation speed (rpm), f: Frequency (Hz), P: Number of motor poles, s: Motor slip) [L1] 2 Types of Inverters [L2] 1) Classification by Use [L4] - Power inverters, motor drive inverters, high-voltage inverters, etc. [L2] 2) Classification by Circuit [L4] - Current Source Inverter equipped with a reactor on the DC side from the output. [L4] - Voltage Source Inverter equipped with a condenser (capacitor). [L2] 3) Classification by Control Method [L4] - PAM (Pulse Amplitude Modulation) which modulates the output amplitude. [L4] - PWM (Pulse Width Modulation) which modulates the output time width.