Effects of unbalanced voltage on the steady-state performance of a five-phase induction motor with three different stator winding connections

Abstract

This paper investigates the adverse effects of unbalanced phase voltage on the steady-state performance of a five-phase induction motor with three different stator winding connections, namely; star, pentagon, and pentacle. Imbalance may occur due to current interruption of one-phase, two adjacent phases, or two non-adjacent phases. Steady-state models based on symmetrical components theory are derived for the three connections. Voltage unbalance factors are calculated using the IEC standard definition for a three-phase induction motor, which is the negative to positive sequence ratio.

Open-Phase Fault Tolerance Techniques of Five-Phase Dual-Rotor Permanent Magnet Synchronous Motor

“…In [21,22], an additional bridge leg is added to the five-phase inverter to eliminate this constraint, and a smooth electromagnetic torque is obtained. References [23][24][25][26] discussed fault-tolerant operation under different stator winding configurations (pentacle, pentagon and star connection), and the result shows that the machine possesses higher fault-tolerance performance and smaller electromagnetic torque ripple when the stator winding is configured in a pentacle or pentagon. In [27,28], based on vectorial approach control and degrees of freedom, fault-operation of a seven-phase axial flux machine is investigated.…”

“…1 " p´15.7541q cospωt+ 25.53˚π 180 q`1.3788cosp3ωt`1 08˚π 180 q i ie 1 " p´15.7541q cospωt´2 5.53˚π 180 q`1.3788cosp3ωt´1 08˚π 180 q (25) in which, ω " 2π f is electrical angular velocity of the machine. From Equation 25, it can be seen that the maximum fundamental amplitude value in injected fault-tolerant currents is 4.47 times of the fundamental current amplitude value under normal conditions.…”

“…When the fault-tolerant currents are injected, the average torque is 17.32 Nm with 8.5% ripple, which is 95.8% of the normal torque, and the ripple is much smaller. (25) in which, ω=2πf is electrical angular velocity of the machine. From Equation 25, it can be seen that the maximum fundamental amplitude value in injected fault-tolerant currents is 4.47 times of the fundamental current amplitude value under normal conditions.…”

“…For five-phase single-rotor PMSM fault-tolerance control strategies, much significant work has been done [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. By injecting proper current in the remaining healthy phases under open-circuit fault conditions, the magnetomotive force (MMF) whose amplitude and rotational speed are the same as normal conditions can be generated [14,15].…”