MTPA/MTPF Control of Interior Permanent Magnet Synchronous Machine by Estimating Inductances

Permanent Magnet Synchronous Machines (PMSM) are more suitable in power train due to the space factor. The size of PMSM is small due to the energy density in the machine is very high. To generate additional torque salient pole PMSM is used since reluctance torque is generated. For accurate design of PI-controllers and for calculating reference currents, the knowledge of machine parameters are needed. Machine parameters are obtained in two ways i.e., either by using lookup tables (experimental methods) or by estimating machine parameters. Inductances are estimated from discrete model of PMSM i.e., online parameter estimator. At each instant inductances are estimated by sensing dc link voltage and current of inverter. Finally these estimated inductances are implemented in MTPA/MTPF (Maximum Torque Per Ampere/Maximum Torque Per field) algorithm to calculate reference direct and quadrature axis currents (i_dref and i_qref).