Modeling, design and control of a 30 hp permanent magnet synchronous motor.

摘要

In this thesis, aspects of modeling, design and control of permanent magnet synchronous motors (PMSMs) are studied. An improved analytical model with stator winding space harmonics included is derived, based on generalized electrical machine theory. Neglecting the space harmonics leads to a simplified d-q equivalent circuit model. These analytical models allow the terminal quantities of a PMSM to be determined. A finite element model is established to obtain the field quantities, with detailed geometry and material characteristics taken into account. Improved post-processing algorithms are developed. Novel torque calculation methods based on Maxwell's stress tenor and co-energy concepts, and a new inductance evaluation algorithm have increased the accuracy and reduced the computing time and effort.;The combination of the analytical method which is used for preliminary design, and the finite element method which is used for fine-tuning the final design, provides an effective methodology for PMSM design. The effects of a wide range of metric variables on the performance of PMSMs are investigated. A set of design criteria are proposed in addition to the design specifications. Using the proposed design methodology, a 30 hp prototype PMSM with NdFeB permanent magnets has been designed, assembled and tested. Various steady state tests of the prototype PMSM are conducted. The close agreement between the test results and those predicted from the analytical model and the finite element model has validated these models, and has confirmed the design.;A microcontroller-based 30 hp transistor inverter system is implemented for the PMSM drive. A complete model for the drive system is established for computer simulation. A modified independent current hysteresis control has been developed and tested, resulting in an improved stator current waveform. A direct torque control strategy is proposed through computer simulation, in order to eliminate torque variations due to space harmonics. The torque control and closed-loop speed control of the prototype PMSM are evaluated through both computer simulation and experiments.