Electrical equivalent circuit for modelling permanent magnet synchronous motors

Esra Kandemir Beser

   In permanent magnet synchronous motor (PMSM) models, only the stator part is given as an electrical circuit and mechanical equations are used for modelling the mechanical part of the machine. In this study, electrical equivalents of mechanical equations are also obtained and mechanical parameters of a PMSM are expressed as an electrical circuit element. In this way, an exact electrical equivalent circuit is proposed in which both the stator and the mechanical part can be modelled as an electrical circuit for the PMSM's dynamic model. Although PMSM model includes mechanical parameters and variables, the complete model is expressed only in electrical elements and variables. The proposed PMSM circuit was simulated for different load torques in the circuit simulation program. Simulation results show that the proposed circuit operates like a PMSM. Simulation results were verified by another method in the form of solution of the differential equations that constitute the mathematical model of PMSM. Due to the proposed circuit that enables the conversion of mechanical parameters into electrical parameters, PMSM can be modelled and simulated as an electrical circuit with completely electrical elements in a circuit simulation program.

Keywords: equivalent circuits, circuit simulation, ac machines, permanent magnet motor, modelling, synchronous motor

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