A computationally efficient iron loss model for brushless AC machines that caters for rated flux and field weakened operation

This paper presents a simple and computationally efficient approach for predicting iron loss within a field orientated controlled brushless AC permanent magnet machine which can cater for both rated flux and field weakened operation. The proposed method is readily incorporated as part of the design process and is based on two discrete time step 2D magnetostatic finite element field solutions describing the open circuit and short circuit operation of the machine. Parameters obtained from these analyses are used alongside the standard d-q equivalent circuit to generate a map for the iron loss across the entire machine working envelope. Test results taken from a concentrated wound brushless AC traction motor are used to validate the technique.