Comparative evaluations of the energy properties of an asynchronous electric drive in transient processes

This article shows the possibility of more effective control of an asynchronous motor with a squirrel- cage rotor than in the formation of an electromagnetic torque under flux linkage stabilization. A comparative analysis of energy properties of asynchronous machine operation under different kinds of control in similar conditions was performed. One means of control provides the premagnetization of the motor and creates electromagnetic torque upon stabilization of the rotor flux linkage in the first control zone, ensuring a transition into the second zone. In another means of control, in accordance with the developed method of sequential synthesis, premagnetization of the motor is not carried out, and at a low rotor rotational speed creates the electromagnetic torque with a minimum of total loss. When the speed increases, the electromagnetic torque is created under the stabilization of efficiency owing to reducing the reactive power in the function of the rotor-rotation speed. With a further increase in speed, the control is fulfilled with a minimum of reactive power, regardless of the motor load. The energy properties of the motor operation were compared depending on the load and rotation speed under the different means of control. The change in the energy properties of electric-drive operation when generating a motor angular velocity up to double the rate under conditions of limitation of voltage of the power-supply source was considered.