Use of Park’s Vector Method for Monitoring the Rotor Condition of an Induction Motor as a Part of the Built-In Diagnostic System of Electric Drives of Transport

Abstract

The article is devoted to the use of Park’s vector method for operational control of the rotor condition of induction motors of traction and auxiliary drives of railway rolling stock. In the course of the analysis, it was established that in order to increase the reliability and efficiency of the operation of vehicles, it is necessary to improve and implement diagnostic systems for monitoring the current state of the most damaged elements of induction electric motors built into the drive. This paper presents the development of a new approach to monitoring the state of a squirrel-cage rotor, which is based on the use of Park’s vector approach. In the course of the research, the issue of taking into account the asymmetric power supply of the engine during the diagnostic period during industrial operation was solved, which affects the accuracy of determining the degree of damage to the rotor. On the basis of the conducted research, the algorithm of the module for diagnosing the state of the squirrel-cage rotor of an induction motor has been developed for practical use in the built-in on-board systems of vehicles, which allows us to determine the degree of damage and monitor the development of the rotor defect during operation, including in automated mode.

Synthesis of the structural diagram with algorithms of the units of the on-board diagnostic system of induction motors of vehicles

“…Violation of the integrity of the rotor winding rods increases acceleration time and additional losses. This leads to a decrease in efficiency and power factor [1,25]. In this case, vibration appears and a significant increase in current strength in the undamaged rods.…”

“…Work [25] presents studies on adapting Park's vector method to determine damage to the rotor winding under an asymmetrical power supply system. When developing an algorithm for determining the degree of rotor damage in the presence of an asymmetrical power supply system, it is also necessary to use recalculation to convert values for currents from a vector diagram from an orthogonalelliptical basis to an orthogonal-circular one.…”

“…10) should be determined. If asymmetry of the voltage system is established (at 0  ), then to determine the exact value of ΔIp it is necessary to recalculate the current values from an orthogonalelliptical basis to an orthogonal-circular one [25].…”

“…The resulting projections for phase currents from Park's drawing , after transformations, can be used both for diagnosing the rotor and for determining damage to the stator. A detailed method for determining rotor defects from a vector drawing of the Park is given in [25] Thus, when comparing the calculated width of the Park`s vector figure with the reference value for a given type of engine, the degree of development of rotor damage is monitored. The rotor condition can be monitored during operation under an asymmetrical voltage system.…”

Research on and Assessment of the Reliability of Railway Transport Systems with Induction Motors

“…These types of damage include turn-to-turn short circuits of the stator winding and the destruction of the winding rods of the squirrel-cage rotor and bearing wear [92,93]. It is not justifiable to consider in the diagnostic system defects that occur due to extreme impacts or emergency loads and lead to sudden catastrophic failures that cannot be foreseen.…”