High fidelity D-Q modeling of synchronous machines using spectral interpolation

This paper presents a dynamic nonlinear dq0 modeling technique for synchronous machines considering magnetic saturation, non-sinusoidal magnetomotive-force, and non-sinusoidal airgap flux density distributions. State-space models are identified from nonlinear finite-element simulations by expanding the flux-linkage and torque dependency on current vector magnitude, current vector angle, and rotor position using tensor product basis functions. A filtering technique is introduced to reduce the complexity of the model based on a user selected criteria. Simulations at different accuracy levels incorporating speed and current controllers, current and voltage constraints, and inverter switching behavior are presented.