Loss Investigation for Multiphase Induction Machine under Open-Circuit Fault Using Field–Circuit Coupling Finite Element Method

Abstract

This paper focuses on the loss estimation for the multiphase induction machine (IM) operating under fault-tolerant conditions through the field–circuit coupling finite element method (FEM). Both one-phase and two-phase open-circuit faults of a seven-phase IM are researched, and different spatial positions of the fault phases are taken into consideration. The magnitudes and phase angles of the residual phase’s current are deduced based on the principle of equal magnitude of the residual phase currents and unchanged fundamental magnetic motive force (MMF). The magnetic fields’ coupling between the fundamental and harmonic planes is analyzed. Then, the time-stepping electromagnetic fields calculation of the seven-phase IM are carried out under the commercial software Simplorer–Maxwell environment. The transient and steady performance for both the health and fault conditions are obtained based on the rotor field-oriented control (RFOC) strategy. The Joule loss and iron loss are calculated for the torque step and slope responses. The seven-phase motor driving platform is established to verify the numerical calculation results. The proposed method is effective for predicting the loss and designing a reasonable operating range for multiphase IM operating under fault-tolerant conditions considering the thermal balance.

Adaline-Based Control Schemes for Non-Sinusoidal Multiphase Drives—Part II: Torque Optimization for Faulty Mode

“…As numerical results, Adaline_Fault has a lower experimental maximum peak current (8.5 A) compared with MTPA_Fault (9.5 A). Adaline_Fault results in lower iron and magnet losses [32,33] The experimental maximum peak voltage reference of phase B is in good accordance with the numerical results in Figure 7a, with 93 V for MTPA_Fault and 89 V for Ada-line_Fault, leading to a higher speed range. Measured phase currents with MTPA_Fault and Adaline_Fault are described in Figure 12a.…”

“…As numerical results, Adaline_Fault has a lower experimental maximum peak current (8.5 A) compared with MTPA_Fault (9.5 A). Adaline_Fault results in lower iron and magnet losses [32,33] harmonics than those of the RFOC scheme using MTPA_Fault do. The current control performance of q-axis currents at 300 rpm is described in Figure 11.…”

“…In addition, Adaline_Fault results in phase currents with lower amplitudes of highorder (≥5) harmonic components as described in Figure 8 for phase-B current. Therefore, iron and magnet losses with the proposed scheme using Adaline_Fault can be lower than those of the RFOC scheme using MTPA_Fault [32,33]. Figure 8.…”

“…As numerical results, Adaline_Fault has a lower experimental maximum peak current (8.5 A) compared with MTPA_Fault (9.5 A). Adaline_Fault results in lower iron and magnet losses [32,33] thanks to lower amplitudes of high-order (≥5) harmonic components of phase currents (see Figure 12b for phase-B current). Experimental copper losses in the remaining healthy phases and the total copper losses in stages 3 and 4 are described in Table 5.…”