Coenergy based transient model of interior permanent synchronous machines

This paper presents the design and analysis of a coenergy based transient model of interior permanent magnet synchronous machines. This model, in qd0 rotating reference frame, was implemented with both FEA and Matlab/Simulink. FEA creates a map of the machine´s magnetic coenergy at a set of currents and rotor positions covering the ranges to be experienced in operation. The machine flux linkages and cogging torques are determined by computing partial differentials of piecewise polynomial representation of the coenergies. The good agreement between the equation calculation and the FEA results validates the feasibility of this coenergy based approach. This approach reduces computational time substantially from that required by a co-simulation approach. Sample transient simulation results demonstrate the application of the proposed model.