Design and Modelling of Axially-Laminated Interior Permanent Magnet Motor Drives for Field-Weakening Applications

Soong, Wen Liang (1993) Design and Modelling of Axially-Laminated Interior Permanent Magnet Motor Drives for Field-Weakening Applications. PhD thesis, University of Glasgow.

Abstract

This thesis is concerned with the design of AC motors to operate at constant shaft power over the widest possible speed range from an inverter of fixed volt-ampere rating. In particular, it examines and validates the reputation of the interior permanent magnet motor drive of having a wide speed range at constant power (field-weakening range). The design and construction of a 7.5kW axially-laminated interior permanent magnet motor showing a constant-power speed range exceeding 7.5:1 is described. This result cannot be matched by any other motor type. Vector-controlled induction motor drives are widely used for field-weakening applications. They offer a constant-power speed range of up to about 4:1. Higher values can be obtained only by oversizing the drive or by using a winding changeover technique. Combined with improvements in low-speed dynamic performance, the inherently wider constant-power speed range makes the interior permanent magnet motor drive a serious contender for applications such as machine tool main spindle drives and traction. The thesis consists of two parts. The first part examines the theoretical and practical limitations to the field-weakening performance of the three types of brushless synchronous AC motor : the surface permanent magnet, the synchronous reluctance and the interior permanent magnet motor. It is shown that high-saliency interior permanent magnet motor drives should offer the best practical field-weakening performance. The axially-laminated (as opposed to the conventional radially-laminated) construction offer the highest saliency ratios. The second part describes the modelling and design of an axially-laminated interior permanent magnet motor drive for optimal field-weakening performance. The effect of varying the design parameters on the drive's field-weakening performance is analysed. A 7.5kW axially-laminated synchronous reluctance and a 7.5kW axially-laminated interior permanent magnet motor were built. The interior permanent magnet motor drive shows an extremely wide constant-power speed range which exceeds 7.5:1.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: T JE Miller
• Keywords: Electrical engineering, Mechanical engineering
• Date of Award: 1993
• Depositing User: Enlighten Team
• Unique ID: glathesis:1993-75707
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 18:33
• Last Modified: 19 Nov 2019 18:33
• URI: https://theses.gla.ac.uk/id/eprint/75707