Abstract
At the present time, almost all of the quick torque control of an induction motor is achieved by vector control or direct torque control methods using CSI (Current-Source Inverter) or VSI (Voltage-Source Inverter) controller. Compared with CSI, VSI has several advantages, such as simple structure, low cost and so on. Consequently, VSI is generally used in induction motor driving systems. However, very quick torque response is hardly attained in VSI systems without the detection of stator current information. This makes the simple structure of VSI rather complicated after all.
In this paper, a new control method to realize very quick torque response of an induction motor system with VSI is proposed. The method developed here employs a PWM voltage-source inverter without the detection of stator current information. The method is based on the explicit mathematical analysis of the two transient terms of the current, and is formulated in a very simple arithmetic manner. For this control, the authors introduced a new concept of pulse addition on the input voltage of an induction motor. Through both numerical simulations and DSP (Digital Signal Processor) system-based experiments, the conceptual validity of the proposed method was successfully confirmed.
