Analysis and control of six-phase induction machines in unbalanced operating situation due to phase opening

Abstract

This paper deals with speed control of a squirrel cage six-phase induction machine (SC6PIM) in phase opening occurrences. A decoupled model of induction machine with unbalanced structure is given to analyze the phase opening operation of the SC6PIM. In order to reduce torque oscillations created in phase opening events, a fault-tolerant operation method by using indirect rotor field oriented control (IRFOC) technique is proposed and used to control the speed of the SC6PIM in each faulty operation. The proposed controller will be renewed in each fault situation of machine regarding the number and type of missed phases. Furthermore, in this paper, switching between controllers in some different cases is investigated and real time initial conditions setting for controllers is proposed to minimize the transient problems in switching instant. To evaluate the performance of proposed method, the experimental results are obtained on a small SC6PIM rated at 90 W.

Sensorless Fault-Tolerant Control Strategy of Six-Phase Induction Machine Based on Harmonic Suppression and Sliding Mode Observer

“…For example, when 'F' phase is opened (j = 1 to 5) and γ = π/2, the (2) gives ϕ 0 = 0 and then, [αβ] T become (3). α β = cos 0 cos σ cos 4σ cos 5σ cos 8σ sin 0 sin σ sin 4σ sin 5σ sin 8σ (3) where σ = π/6. The electromechanical energy conversion takes place only in αβ-subspace which means that the MMF produced by active phases is equivalent to the MMF produced by two windings on the axes α and β with the currentsi sα and i sβ , respectively.…”

“…Fault-tolerant control strategies for multiphase motors can be roughly divided into three types: field-oriented control, direct torque control and optimal current control based on open-phase decoupling mathematical model. The first control method was suggested by Y.Zhao [2], [3], and the basic idea is that according to the situation of open-phases, the mathematical model of the unbalanced state is established through the space decoupling transformation and asymmetric rotation transformation after open-phases fault. Finally, the field orientation control under unbalanced state is established.…”

MRAS-based Sensorless Speed Integral Backstepping Control for Induction Machine, using a Flux Backstepping Observer

“…Due to these constraints, research was carried for other solutions, exploiting the AC machines and especially the squirrel cage induction motors (IM) [3].The IM has certain advantages related to its simple design, robustness, low cost and maintenance. Also, it is widely used in many fields such as aerospace, rail and marine traction, transportation systems and in a multitude of industrial applications (machine tools, driving machines, pumping systems, ventilation and lifting [4].…”