EXPERIMENTAL RESEARCH METHOD OF ADAPTIVE ESTIMATION PARAMETERS OPEN WOUND-ROTOR INDUCTION MOTOR IN A STEADY STATE MODE
Authors:   Gazprom transgaz Tomsk, Rakov Ivan 
Published: May 2022

Relevance For the operation of a closed-loop sensorless electric drive as part of an electrical complex, it is necessary to ensure adequate restoration of the vector of state variables of an induction motor using a customizable mathematical model in the control system. The accuracy of restoring the state variable vector depends on two factors. The first factor is the mathematical description of the substitution circuit of an asynchronous motor by a system of differential equations with certain assumptions that reliably reflects the physical processes occurring in an asynchronous motor. Used in the electric drive control system, T- and L-shaped equivaent circuits of an asynchronous motor, described by a system of differential equations in a customizable mathematical model, are universal and allow simulating the behavior of an asynchronous motor in all operating modes: «start», «load surge», «load shedding», «reverse», «stop», which is a sufficient condition for their use without modifications within the framework of this article. The second factor — the coefficients in the system of differential equations with some error correspond to the electrical parameters of the equivalent circuit of an asynchronous motor. In turn, the electrical parameters of the equivalent circuit of an asynchronous motor are unique for each motor and cannot be used in a system of differential equations without their refinement, i.e. no identification process. There are several types of identification of the electrical parameters of an induction motor: by the experience of idling and short circuit, by catalog data, by induction motor attenuation with a locked rotor of an induction motor, and others. The described methods for identifying parameters in most cases require the decommissioning of an asynchronous motor and conducting separate experimental studies, after which the electrical parameters in the equivalent circuit are considered constant and unchanged during operation. It is known that when an asynchronous motor is heated during operation, the active resistances of the stator and rotor circuits change. The inductance of the main magnetization circuit, stator and rotor circuits vary depending on the shape of the supply voltage and the operating modes of the asynchronous motor. Changing these parameters means that the restoration of the state variable vector will occur with a larger error. Given the above, the development of a methodology for adaptive identification of the electrical parameters of the equivalent circuit of an asynchronous motor during operation, without decommissioning and shutting down the entire electrical complex, is an urgent scientific and practically significant task. Aim of research Development and experimental study of a method for determining the electrical parameters of the stator winding in steady-state operation modes without decommissioning and stopping the electrical complex. Research methods Systems of nonlinear equations, iterative procedures, Newton's method, numerical methods, state space method, optimization methods. Results A method of adaptive identification of the electrical parameters of the stator winding replacement circuit in steady-state operation based on the power balance has developed and experimentally tested, which allows for accurate estimation of the parameters of the stator winding replacement circuit during induction motor operation. The developed technique in the future, with the expansion of the mathematical apparatus, will allow determining the parameters of both the stator and rotor windings of the induction motor when the electric drive is operating as part of an electrical complex. The practical application of open woundrotor induction motor is not possible, therefore this article is of a research nature and is intended only for experimental confirmation of the operation of the technique.