Analyzing Fault Tolerance in a 1.3 kw Six-Phase Fully Coreless Axial-Flux Permanent-Magnet Generator

The importance of fault-tolerant machines is growing rapidly as the electrical machine industry demands uninterrupted operational service in the context of the Fourth Industrial Revolution. Additionally, coreless axial-flux permanent-magnet (AFPM) machines have emerged as efficient solutions for power generation in recent industries, offering advantages such as reduced eddy current losses and cogging torque, thereby improving overall efficiency. This design supports high power density, particularly in fully coreless configurations. However, challenges like high leakage flux and reduced structural integrity hinder the widespread adoption of coreless AFPM machines. Moreover, integrating multi-phase setups in AFPM machines is more complex than in radial-flux permanent-magnet (RFPM) machines, as it requires more winding coils and increases the stator diameter, resulting in bulkier designs. This article emphasizes the fault tolerance performance of a 1.3 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{kW}$</tex> lightweight, fully coreless six-phase AFPM generator for small-scale power generation. To achieve this, a six-phase multi-stage AFPM generator was designed and simulated using ANSYS Maxwell®. Subsequently, a laboratory-scale prototype was fabricated accordingly. Three types of winding configurations were applied to the six-phase machine to evaluate the fault tolerance performance of each type. The fault tolerance performance was found to closely align with that of a referenced RFPM machine. Notably, the fully coreless six-phase machine demonstrated a significant power density of 205 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{W}/\mathbf{kg}$</tex>, along with high fault-tolerant capacity.