Motor Mode Analysis of Exterior-Rotor PM Machine with Gramme’s Winding

Rene Nukki,Kristjan Tiimus Sr,Aleksander Kilk,Samo Saarts

doi:10.5755/j01.eie.23.1.17579

Abstract

This paper presents the PM electrical machine with the novel stator geometry, which is intended for a small unmanned aircraft. The PM machine is a part of a hybrid propulsion system operating in conjunction with an internal combustion engine. The main study involves operations in the motor mode, where the PM electric machine performs as the main propulsion, as well as the additional power source or a starter in the hybrid drive. The purpose of the investigation is experimental evaluation of the electric parameters of the PM electric machine in the motor mode; in particular, achievable torque at different speeds on several loads, to compare the results with the initial requirements.DOI: http://dx.doi.org/10.5755/j01.eie.23.1.17579

Highlights

Today small unmanned aerial electric vehicles (UAV) are used for a wide range of purposes, like wildlife tracking, traffic monitoring, border patrols, environmental research, geographical mapping, numerous military applications and several more [1]
Hybrid propulsion systems (HPS), which have proven itself in the land and in the maritime transport [2] have started to expand into the field of UAVs
The performed thermal experiments indicated significantly higher power and current density handling capabilities of exterior-rotor permanent magnet synchronous machine (ERPMSM) with forced cooling provided by the propeller while keeping other machine active parts at notably lower constant temperatures. Based on this experimental work it can be concluded that ERPMSM fulfils the initial requirements set as a primary propulsion element, either working in parallel with internal combustion engine (ICE) or in starter mode in UAVs stable flying or in take-off regimes at the provided propeller pitch

Summary

INTRODUCTION

Today small unmanned aerial electric vehicles (UAV) are used for a wide range of purposes, like wildlife tracking, traffic monitoring, border patrols, environmental research, geographical mapping, numerous military applications and several more [1]. The novelty of the research lies in implementation of a new type of stator geometry in the exterior-rotor permanent magnet synchronous machine (ERPMSM) in combination with Gramme's or toroidal winding, in usage of this kind of ERPMSM in a motor, as well as in a generator operation in an HPS for a small-size UAV. The choice of the ERPMSM’s topology was determined by basic requirements, such as simple construction, low cost, high power-to-weight and power-to-volume ratio, smallest size, good control options and high torque at low speed In this case, the exterior-rotor topology has several advantages. In this study the main focus is on the ability of ERPMSM to work as a motor This includes its capability to function as a primary engine which directly rotates a propeller, operates in parallel with ICE as a starter or giving extra power during UAV’s take off. During the research the prototype of ERPMSM was constructed (Fig. 3)

INITIAL PARAMETERS

LOAD TESTS

THERMAL CHARACTERISATION

Findings

CONCLUSIONS