MATRIX Motor with Individual Control Capability for Iron Loss Suppression under Flux Weakening Control

Abstract

Interior type permanent magnet synchronous motors (IPMSMs) have been widely used for various applications because of their high efficiency and high power density. It is well known that the flux weakening control of an IPMSM can extend the operating range by reducing the back-EMF and producing reluctance torque. An IPMSM, however, experiences a large harmonic iron loss in the stator teeth caused by the distorted flux density. In particular, the harmonic eddy current loss significantly increases in the high speed region under flux weakening control.This paper describes a novel motor-drive system that includes an individual multi-phase drive in order to control the current and voltage in each armature winding. The proposed system can be expected to achieve high efficiency driving, a wide operating range, fail-safety and so on. Furthermore, the proposed method gives the distorted flux density distribution a sinusoidal waveform, because the individual control can observe and regulate the instantaneous flux linkage in each stator tooth, although the motor consists of a full-pitch distributed winding. Therefore, the proposed drive can suppress the harmonic iron loss under the flux weakening operation. Simulation and experimental results show that the proposed method can achieve an extensive reduction in the total iron loss in particular in the high speed region.

A research trend of electric machines with development of finite element analysis

“…In Ref. [17], the authors investigate the novel control method to suppress the iron loss by a multiphase drive. In the case of IPMSM, it is known that the flux weakening control causes a large harmonic iron loss due to the distorted flux density.…”

“…These achievements have been highlighted by many researchers who have proposed novel approaches to improve motor performance. Three groups of topics will be introduced in this paper: optimal design methods [1][2][3][4][5][6][7][8][9], novel motor structures [10][11][12][13][14][15][16], and novel control methods [17][18][19][20].…”

Larger torque production strategy of multi-phase inverter-fed MATRIX motor using air-gap flux density

“…It is investigated that the proposed method can change the torque ripple depending on the load conditions [11]. Furthermore, the suppression method of the iron loss is also proposed by the arbitrary excitation of independent inverters [12]. The configuration of the open-winding connected with H-bridge inverter can control the local flux density in each stator tooth and thereby can reduce the iron loss by deforming the distorted flux density to substantially sinusoidal waveform.…”