Electrical Machines And Drives A Space Vector Theory Approach Monographs In Electrical And Electronic Engineering Site

$$\frac{d\vec{\psi}_s}{dt} = \vec{v}_s - R_s \vec{i}_s$$

$$\vec{v}_s = R_s \vec{i}_s + \frac{d\vec{\psi}_s}{dt} + j \omega_k \vec{\psi}_s$$

where $\omega_k$ is the speed of the chosen reference frame (stationary, rotor, synchronous). The torque expression unifies as:

$$T_e = \frac{3}{2} p \cdot \text{Im} { \vec{\psi}_s \cdot \vec{i}_s^* } = \frac{3}{2} p (\vec{\psi}_s \times \vec{i}_s)$$

Difference between machine types is merely a matter of flux generation: $\vec{\psi}_s = L_s \vec{i}_s$ (IM), $\vec{\psi}_s = L_s \vec{i} s + \vec{\psi} {PM}$ (PMSM), or $\vec{\psi}_s = L_s \vec{i}_s + L_m \vec{i}_r'$ (DFIM). The drive —the control algorithm—does not need to know the difference beyond the flux linkage map.