Design of optimal digital controller for stable super-high-speed permanent-magnet synchronous motor

Abstract

A new collaborative design scheme of a super-high-speed permanent-magnet synchronous motor (PMSM) and its digital controller is presented, which provides a low-cost but highly efficient motor system with guaranteed stability and performance. Since the systematic design of the PMSM can ensure its stability over the full operating speed range, a simple and reliable open-loop controller can be designed for the super-high-speed motor. With stability assurance, an optimal digital control is also designed in order to enhance the efficiency and performance of the PMSM. The unique feature in the proposed optimal V/f control is its design consideration to the stator resistor, which is generally neglected in most V/f controls but cannot be neglected in the super-high-speed motor owing to the extra small-size requirement. The simulation and stability analysis for various design options are provided. Finally, simulation and experimental results validate the design technique and its effectiveness.

Limits, Modeling and Design of High-Speed Permanent Magnet Machines

“…The method has been repeatedly analyzed in literature [195,[197][198][199][200][201][202]; it will be shortly recounted here.…”

“…Fortunately, applications where high-speed PMSM are used usually require no high performance of the speed control so that open-loop controllers can be used [29,195,197]. The open-loop control method that is mostly used for high-speed PMSM is V/f control with fre-quency modulation.…”

“…In order to achieve stability, however, the reference frequency is modulated using perturbations of the active power and this frequency modulation, in effect, introduces necessary damping to the speed response. The method has been used regularly in open-loop control of high-speed PM machines [195,[197][198][199]; moreover, Itoh et al [198] showed that, at high speeds, performance of this method is as good as or even better than performance of the sensorless vector control.…”

Sensorless V/f Control of Permanent Magnet Synchronous Motors

“…When the motor operating at low speed or at high load level, maintaining the relation constant does not maintains the flux constant, diminishing motor performance [14,15]. In super-high-speed PMSM, with very low inductance, the stator resistance cannot be neglected even at high speeds [16]. Therefore, it is necessary to compensate the resistive voltage droop in the applied voltage.…”

Study on Direct Torque Control of Super High-speed PMSM

“…Due to the features such as high efficiency, small volume and high power density, super high-speed permanent magnet synchronous motor (PMSM) are becoming attractive in many fields [2] [3]. when PMSM drives are used for applications like micro-turbine generators, pumps and fans, where the load is predictable and high dynamic performance is not a demand, V/f control method is the most popular method of speed control because of it simplicity and easy to realize [4] [5]. For ordinary motor, the V/f control curve is a straight line with a boost voltage because the stator resister is negligible.…”