Calculation of Slot Leakage Flux Using Equivalent Magnetic Circuits

This paper presents the limitations of the common approach to calculate the slot leakage flux in AC machines with equivalent magnetic circuits. It delivers a method that improves accuracy and enables leakage flux calculation even at high saturation. Using equivalent magnetic circuits in this case results in the problem to find the right leakage flux permeance which is shown with a simple test model. The solution delivered by this paper is the use of the frozen permeability method which gets validated by comparing FEM and analytical results. The results show a significant increase in accuracy by this method, compared to the common approach, but it is still limited by the magnetic voltage drop in the iron parts. The proceeding from this test model can be adapted to flux leakage paths in electrical machines.