Dynamic and steady state performance comparison of line-start permanent magnet synchronous motors with interior and surface rotor magnets

Abstract

A comprehensive comparison of the dynamic and steady state performance characteristics of permanent magnet synchronous motors (PMSM) with interior and surface rotor magnets for line-start operation is presented. The dynamic model equations of the PMSM, with damper windings, are utilized for dynamic studies. Two typical loading scenarios are examined: step and ramp loading. The interior permanent magnet synchronous motor (IPMSM) showed superior asynchronous performance under no load, attaining faster synchronism compared to the surface permanent magnet synchronous motor (SPMSM). With step load of 10 Nm at 2 s the combined effect of the excitation and the reluctance torque forced the IPMSM to pull into synchronism faster than the SPMSM which lacks saliency. The ability of the motors to withstand gradual load increase, in the synchronous mode, was examined using ramp loading starting from zero at 2 s. SPMSM lost synchronism at 12 s under 11 Nm load while the IPMSM sustained synchronism until 41 seconds under 40 Nm load. This clearly suggests that the IPMSM has superior load-withstand capability. The superiority is further buttressed with the steady state torque analysis where airgap torque in IPMSM is enhanced by the reluctance torque within 90E to 180E torque angle.

A simplified sensorless speed control of permanent magnet synchronous motor using model reference adaptive system

“…Permanent magnet synchronous motors (PMSMs) are widely used in low and medium power applications such as computer peripheral equipment, robotics, adjustable speed drives and electric vehicles [1]. With lots of advantages, such as high torque density, small size and low maintenance cost, the permanent magnet synchronous motors (PMSMs) find wide applications at home and in industries [2,3,4].…”

Methodology for Cage Shape Optimization of a Permanent Magnet Synchronous Motor Under Line Start Conditions

“…The parameters resulting in the best starting performance of the line start permanent magnet synchronous motor motor (LSPMSM) are normally different to the optimal design for synchronous operation (efficiency and power factor) [1], [2], thus it is advisable to conduct a multiobjective search to account for all conflicting requirements. This type of optimization is very time consuming if full numerical modeling is used; in this paper, efficient design strategies are considered as well as ways of extracting motor parameters from field solutions.…”

Asynchronous slip-ring motor synchronized with permanent magnets

“…The designs of motors with a cage rotor winding and permanent magnets built into a rotor core are known [2,5,6]. The cage winding is made up of copper bars placed in slots along the outer rotor circumference; at the coil outhangs the bars are short-circuited with the rings.…”

“…electromagnetic resultant torque, generated by the cage winding and permanent magnets, in the range of speeds from 0 to about half the rated speed (0 ≤ n ≈ 0.5n N ) may be less than motor's rated torque. The motors with the cage winding and permanent magnets play their role in the drives of mechanical devices and machines with small start-up loads and short start-up times [2,5]. These conditions are fulfilled by pumps and fans, where the load torque is proportional to the quadratic function of the speed.…”