Vector control of unbalanced 3-phase IM using forward and backward components

Abstract

Abstract:In some industries, continuous operation of 3-phase induction motors (IMs) even under faults until the scheduled maintenance time is essential. Conventional control techniques such as field-oriented control (FOC) cannot be used to control faulty IMs since this will result in significant oscillations in the speed and torque. Consequently, a new control approach must be developed for improving IM performance during fault conditions. This paper presents a method for vector control of 3-phase IMs under open-phase faults. The main advantage of this control scheme is its ability to handle not only one phase but also two phases of open-phase fault conditions. When applying this control technique to a faulty machine, only minor changes to the parameters used in the equations are needed and the conventional FOC algorithm used for healthy 3-phase IMs can still be used. In this paper, simulation and experimental results are presented to study the effectiveness of the proposed technique to control both healthy and faulty 3-phase IMs. The results show that the proposed technique reduces electromagnetic torque pulsations during open-phase fault conditions.

Indirect field‐oriented controlofstar‐connected three‐phaseinduction machine drives againstsingle‐phase open‐circuitfault

“…In this case, the introduced control system has a simple structure in comparison to the previous works by Gaeid et al 20 and Jannati and Idris. 21 • The proposed control scheme in this paper has a better performance compared to the existing FOC models such as those proposed by Nikpayam et al, 4 Tabasian et al, 22 and Nikpayam et al 23 in terms of torque and speed ripples due to considering L ls in the FOC equations. • The introduced control system has a high accuracy like Abbasi et al 24 However, unlike Abbasi et al 24 the proposed FOC method in this paper does not include derivative terms in the vector model equations since an asymmetrical TM is used for stator voltage quantities.…”

“…Different control strategies for star-connected and delta-connected TPIMs under SOF were reported in previous studies. 4,[13][14][15][16][17][18][19][20][21][22][23][24] In studies by Sayed-Ahmed et al, 14 Kastha and Bose, 15 and Sayed-Ahmed and Demerdash 16 different scalar control schemes were presented for TPIMs under SOF. Scalar control strategies are not considered as a suitable control system due to slow reaction to transient.…”

Post‐fault operation strategy for single open‐phase fault in three‐phase induction motor drives

“…However, these methods are not precise RFOC models because of the leakage inductance elimination in the RFOC equations. In [25], an indirect RFOC technique for wye‐connected TPIM drives during SOPF condition using the conventional transformation matrix has been presented. Nevertheless, this method has complex structure because of using many PI controllers and two RFOC systems.…”

“…It is worth noting that in [22–24], two different asymmetrical transformation matrices were used in the control system. The proposed strategy aimed to retain the RFOC structure even during post‐fault operation. In this case, the introduced control method in this research has a simple control structure compared to [25]. The used direct RFOC system in this research has good performance at low speed operation compared to indirect RFOC systems in [23, 25, 27, 28] due to the rotor flux estimation.…”

“…Besides the inverter topology reconfiguration, some modifications in the control structure during post-fault operation are required. Different control strategies have been proposed to manage SOPF of delta-connected TPIM drives [20,21] and wye-connected TPIM drives [3,17,[22][23][24][25][26][27][28][29]. Vector control techniques for wye-connected TPIM drives during open-phase fault have been proposed in [17,26] based on preserving the fundamental magneto-motive force (MMF) unchanged during prefault and post-fault operations.…”