Progress in the transistor inverter technologies for motor drives

One of the most important aspects of power electronics is energy saving. Here, energy savings capabilities achieved by variable speed motor drives are introduced during acceleration, deceleration and continuous operation. When a motor is running at a certain speed, kinetic energy is stored in the mechanical system. If the motor was started by directly applying power, almost the same amount of energy must have been dissipated in the motor as loss. Similarly when you stop the motor, the kinetic energy stored in the motor is usually dissipated as the loss. If the power is controlled appropriately by a converter during the acceleration, and if the kinetic energy is recovered to the power source during deceleration or temporarily stored for the next acceleration, this large amount of energy loss can be minimized. Energy saving during continuous operation will also be introduced in the key-note lecture. As a brief history of PWM inverter drives, earlier models both in open-loop PWM control and closed-loop vector control will be explained.