ALGORITHM FOR ASYNCHRONOUS ELECTRIC DRIVE VECTOR CONTROL WITH ROTOR RESISTANCE ESTIMATION

Abstract

To implement the vector control by the asynchronous motor, it is necessary to have information about the resistance of the rotor winding, which can be significantly changed during the operation of the engine. The main reason for changing the resistance of the electrical machine windings is their heating. In addition, a priori information about the resistance of the rotor is unreliable. An error in estimating the impedance of the rotor winding leads to a decrease in the quality of control. Reducing the quality of the control consists in changing the value of the electromagnetic moment and reducing the speed control range. To solve this problem, an algorithm for identifying the impedance of rotary winding of the asynchronous motor, which allows to assess it, without resorting to complex algorithms and calculations. The basis for the implementation of the proposed algorithm is a modified vector control that uses special differential equations of the vector control. The presence of discrepancy in stationary vector control equations indicates errors in a priori resistance assessment. The special differential equations of stress residuals, which allow dynamically adjusting a priori information about the rotor resistance, as well as taking into account its temperature fluctuations during operation, are proposed in the paper. To implement this algorithm, it is necessary to obtain information about the currents occurring in the phase windings of the stator and the speed of rotation of the asynchronous motor rotor. A computer modeling, confirming the performance of the algorithm presented is completed in the paper. The rendered algorithm for estimating the rotor resistance is fairly simple in implementation and does not require large computational costs, which highlights it among other well-known algorithms. This algorithm is recommended for use in vector systems of asynchronous engines management, including powerful propulsion motors on the water transport facilities.