Energy-Saving Research on Asynchronous Motor Voltage Regulation Using Γ Equivalent Circuit

In order to study the energy-saving control of the motor terminal voltage regulating according to the load change, this chapter investigated the asynchronous motor loss based on the Γ-shaped equivalent circuit. The electrical loss in the motor is divided into two parts, of which one is the loss with the terminal voltage changes and the other is the loss with the load changes. And the calculation formulas about the two kinds of loss are derived. The mathematical model is obtained which reveals the relation of the minimum loss corresponding to the optimal operating voltage. Considering the practical application, the calculation method, which computes the optimal motor operating voltage, is obtained. In the computing model, the input power and the stator voltage are treated as the measurable inputs. The experimental results show that the voltage regulation method can improve the operating efficiency of the asynchronous motor, especially in the conditions of light load at which the energy-saving effect is more pronounced. In the case of variable load, the calculating method getting the motor’s optimal operating voltage based on the field online measurable inputs can satisfy the requirement of voltage regulating and energy saving in the asynchronous motor. The method also has the characteristics of good engineering applications and real-time property and can achieve a good energy-saving effect.