energies Article Design and Realization of a Hybrid Excited Flux Switching Vernier Machine for Renewable Energy Conversion Haidar Diab 1 , Yacine Amara 1, * , Sami Hlioui 2 and Johannes J. H. Paulides 3   Citation: Diab, H.; Amara, Y.; Hlioui, S.; Paulides, J.J.H. Design and Realization of a Hybrid Excited Flux Switching Vernier Machine for Renewable Energy Conversion. Energies 2021, 14, 6060. https:// doi.org/10.3390/en14196060 Academic Editor: Audrius Bagdanavicius Received: 29 July 2021 Accepted: 18 September 2021 Published: 23 September 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 GREAH, Université Le Havre Normandie, 76600 Le Havre, France; haidar.diab@univ-lehavre.fr 2 SATIE, Conservatoire National des Arts et Métiers, 75003 Paris, France; sami.hlioui@cnam.fr 3 Advanced Electromagnetics B.V., Industrieweg 78, 5145 PW Waalwijk, The Netherlands; johan@ae-grp.nl * Correspondence: yacine.amara@univ-lehavre.fr Abstract: This paper presents the design of a hybrid excited flux switching Vernier machine. This machine is designed to serve in renewable energy conversion applications, such as a wind turbine generator, or tidal turbine generator. After introducing this original structure, a design based on finite element models is conducted. The specifications correspond to relatively low power direct drive wind or tidal turbine applications. The rated power is set to 10 kW, with a rated speed of 300 rpm. Mainly the electromagnetic design is presented. Aspects related to the realization of a prototype are also presented, and an experimental study is included. Keywords: hybrid excitation; Vernier effect; flux switching; renewable energy; wind turbine; tidal turbine 1. Introduction Problems linked to the use of fossil fuels are pushing our societies to find viable and sustainable alternatives for their replacement. The use of nuclear energy, even if it emits less polluting greenhouse gases, does not cause fewer problems. Indeed, radioactive wastes, the products of nuclear power plants, have a lifespan that exceeds several generations, the management of which is problematic. In this context, renewable energies constitute a viable and lasting solution, since their potential is enormous, and they do not emit greenhouse gases. The French Environment and Energy Management Agency (Ademe), aims that France should produce, by 2050, 100% of its electrical energy from renewable energies at acceptable economic costs [1]. Among the different renewable energy sources, marine renewable energies (MRE), i.e., offshore wind, wave energy (wave power) and tidal turbines, are those that offer the least intermittency problems [2]. Tidal turbines, for example, harness the energy of oceanic marine currents which are continuous over time, or that of tidal currents which are relatively predictable [2]. France has a strong development potential for MRE, given the natural assets of its territory (11 million km 2 of water under its jurisdiction) [3]. This known resource, estimated between 2 and 3 GW, is mainly concentrated offthe coasts of Normandy, Brittany and Pays de la Loire [3]. In this paper, the electromagnetic design of a hybrid excited flux switching syn- chronous machine with a Vernier effect is presented [4]. Its structure is inspired by works carried out on flux switching machines which include hybrid excitation [5–7], and those including the Vernier effect [8,9]. A similar structure was the subject of a Chinese patent [4]. Such structures can be qualified as original, and are not well studied. Furthermore, the structure studied in this research also includes damper windings used for the mitigation of voltage induced in the wound field excitation windings [10–14]. This structure can be used as a generator (alternator) in low-speed applications such as direct drive wind turbines or tidal turbines. After a presentation of the structure of this machine, sizing based on finite element method models is proposed. The sizing is carried out on the basis of specifications Energies 2021, 14, 6060. https://doi.org/10.3390/en14196060 https://www.mdpi.com/journal/energies