Synthesis of load moment observerasynchronous electric drive with vector control

Abstract

Purpose. The energy characteristics of asynchronous electric drives in steady-state operation are functions of three variables: the angular speed rotation of the rotor, the module of the vector flux coupling of the rotor and the moment load. The moment of load is an external disturbing influence, effective methods of its measurement are not available. Therefore, the purpose of this paper is to mathematically describe the observer of the state variables of the active power channel and the load moment on the shaft of an asynchronous electric drive with vector control. Methodology. To achieve the purpose of the work, the method of synthesis modal observers is applied using the field-oriented model of the asynchronous machine with the decomposition of its equations and taking into account the nonlinearities of cross-connections between the control channels. Results. As part of the relay-vector control system, a modal observer of the load moment is synthesized, the information from the output of which can be used to build algorithms for extreme control of an asynchronous electric drive. The asymptotic stability is proved by the method of mathematical modeling and is sufficient the accuracy of the observer of the load moment at different distributions of the roots its characteristic equation. Scientific novelty. Thepaper solves the actual scientific problem of establishing the regularities of the structural-algorithmic synthesis and tuning of the modal observer of the moment of load on the shaft of an asynchronous electric drive. Identification of the moment load on the shaft of an electric machine will allow to improve the quality indicators of extreme control systems of asynchronous electric drives. Practical significance. The obtained equations of the observer determine the load moment identification algorithm, the information about which can be used in two-channel vector control systems for asynchronous electric drives to build an external extreme control circuit, which improves the energy performance of the asynchronous machine. First of all, we are talking about minimizing the loss of active power or the consumption of reactive power an asynchronous machine when the load moment on its shaft changes.