Analytical Model of an inverter-fed electrically excited synchronous motor considering saturation

An analytical model for the calculation of the steady-state behavior of an inverter-fed electrically excited synchronous motor is presented in this paper. The air-gap field is modulated with a magnetic permeance function. From this, position-dependent inductances can be derived. These inductances are used by the mathematical model of the machine that describes its dynamic behavior, when it is fed by a power electronics inverter. For the calculation of the currents and the torque, the voltage equations are rearranged depending on the switching state of the inverter and solved by numerical integration. The magnetic saturation effect is taken into account with a factor that is calculated based on the mean level of saturation. The analytical model is verified by comparing it with numerical finite element method calculations.