Three-Phase Inverter Fed Adjustable Field IPMSM Drive Utilizing Zero-Sequence Current

Abstract

This article proposes a three-phase four-wire inverter drive system for an adjustable field interior permanent magnet synchronous motor utilizing magnetic saturation. The magnetic saturation is regarded as a phenomenon of a decrease in permeability depending on an extra magnetic field. In the proposed motor, the number of flux linkage can be controlled by modulating the permeability of magnetic leakage paths in the rotor. However, the proposed adjustable field method requires an additional magnetomotive force (m.m.f.) to control the permeability. Therefore, a zero-sequence current i z fed by the three-phase four-wire inverter is utilized as the additional m.m.f. source. Thereby, the field control can be achieved with a simple three-phase inverter without sacrificing the number of switching devices compared with conventional motor drives. In the article, the control algorithm of the three-phase four-wire inverter is discussed, and its usefulness is verified by comparing the proposed drive system with other methods or systems.

High-Efficiency Drive Method of Adjustable Field IPMSM Utilizing Magnetic Saturation

“…As a result, it has been revealed that the proposed drive circuit is more straightforward and efficient in terms of system volume and switching loss than the conventional adjustable field PMSM drive system. In addition, the references [13] and [14] revealed that the proposed adjustable field method could achieve field control with lower copper loss and harmonics than the conventional field weakening control [15]- [19].…”

“…In recent years, adjustable field PMSMs have been widely researched for driving range expansion [1]- [12]. The authors also have studied the adjustable field IPMSM focusing on the magnetic saturation of a soft magnetic material [13] and [14]. We call the motor the adjustable field IPMSM based on permeability modulation because the motor can control the magnetic field while modulating the permeability of the magnetic leakage paths between PMs.…”

“…In the reference [13], it could be confirmed that the prototype of the adjustable field IPMSM based on permeability modulation can expand the driving range utilizing magnetic field control. In the reference [14], a three-phase four-wire inverter was introduced as a drive circuit for the prototype motor. The three-phase four-wire inverter can supply a square wave zero-sequence current to the prototype in addition to the daxis current i d and the q-axis current i q .…”

“…In contrast to these references [13] and [14], this paper examines a new added value of adjustable field IPMSM, which is to expand the high-efficiency driving range. Fig.…”

“…Comparing the efficiencies in the driving range common to the NT characteristics of both PMSMs, the PMSM with the high Ψ f can achieve a high-efficiency drive at the high torque operating point because the armature current to deliver the high torque can be reduced. In contrast, since the significant loss at the low-toque-high-speed operating point is iron loss, not copper loss, the efficiency at the low-torque- [1]- [5] Not good Good Variable leakage flux motor [6]- [8] Good Not good MATRIX motor [9], [10] Not good Good Hybrid motor [11], [12] Good Good Proposed adjustable field IPMSM [13], [14] Good Good…”