Application of Lagrange multiplier estimation to the design optimization of permanent magnet synchronous machines

Sensitivity analysis with Lagrange multiplier estimation is performed in order to find the most appropriate design of synchronous machines with rare-earth magnet excitation and current source inverter supply. Numerical field calculation and mathematical vector-optimization methods are applied in order to solve the nonlinear optimization problem. The efficient use of these procedures is demonstrated by the comparison of two different magnet configurations in the rotor of the machine. It is shown that the magnet material savings for the rotor with interior tangential magnets increases with increasing power output due to the flux-squeezing effect