A Method for Constructing Synchronous Electrical Machine Equivalent Circuit Models for Motor-Drive Co-Simulation

The paper introduces a method to model various synchronous electrical machines called the equivalent circuit model (ECM). The purpose of developing ECM is to present an efficient machine model that is feasible for motor-drive co-simulation. The features include (1) rapid computation for motor-drive co-simulation with voltage source inverters and controllers, (2) capability of simulating electromagnetic nonlinearities such as saturation and harmonics, (3) identical interface as a standard electrical component that can be implemented in circuit simulation tools directly, and (4) generalized construction to let most applications can utilize the proposed method. The proposed ECM consists of three parts: (1) mathematical model to represent the physics, (2) pre-processed flux linkage database from finite element analysis (FEA) results, experiments, or other reliable databases, and (3) equivalent circuit components that link the mathematical model to the circuit model in simulation software. Synchronous electrical machines, including a three-phase synchronous machine (3ϕSM), open-end-winding synchronous machine (OEWSM), electric-excited synchronous machine (EESM), and dual-three-phase synchronous machine (D3ϕSM), were investigated to validate the functionality of the proposed method. In these cases, FEA models were used as a reference. According to the results, the computation time of performing ECM was significantly shorter than that of FEA, while the relative error was acceptable in the studied cases. Finally, the ECM-based motor-drive co-simulation was demonstrated and compared with an actual motor-drive system under various operating conditions.