Capacitor excited single phase brushless generator design and modelling using dq variables

This paper describes a method for deriving the steady-state performance equations of a brushless, capacitor-excited single-phase synchronous generator. The machine is modeled as a balanced two-phase synchronous generator with unbalanced loads. By referring the unbalanced winding currents to the synchronous (rotating) reference frame, dq flux equations are derived that include the effects of damper bars and saturation in both the d- and q- axes. From the resulting voltage equations, steady-state currents are solved for. The performance equations can also be extended to various types of single-phase synchronous machines. An iterative approach is used to solve for steady-state operating points. The model is verified using data from an actual brushless generator at various excitation levels.