On the approximation of the state equations of nonlinear permanent magnet synchronous motors

This paper presents an approximate linearized model for permanent-magnet synchronous motors. The linearized model is derived using an optimization technique, which is obtained by minimizing a cost function for a particular solution. Numerical experiments show good agreement of the method with the nonlinear system for both autonomous and non-autonomous cases. It turns out that unlike the classical linearization, the linearization method used here is not a first order approximation, but has the same order as the nonlinearity. The method can be used for the control of different types of permanent magnet synchronous motors