IEEE TRANSACTIONS ON MAGNETICS, VOL. 48, NO. 6, JUNE 2012 2035 A New Concept of Modular Permanent Magnet and Soft Magnetic Compound Motor Dedicated to Widespread Application C. Henaux, B. Nogarede, and D. Harribey University of Toulouse, INPT—LAPLACE Toulouse 31071, France This paper deals with the design and test of a permanent-magnet machine based on a novel modular stator concept. The manufac- turing and recycling costs are minimized thanks to the use of composite magnetic materials (plastic bonded magnets, soft magnetic composites). The main properties of composite magnetic materials, from a magnetic and mechanical point of view, are briefly presented in the first part of this paper. After focusing on their thermal properties by detailing a thermal experimental study, the proposed concept of a modular permanent-magnet machine is described. Experimental characterization of the realized prototype, in static and dynamic operating modes, demonstrates its advantages compared with conventional structures. Index Terms—Brushless motor, economic cost, lamination, manufacturing process, permanent-magnet motors, prototype, soft mag- netic materials, temperature measurement, thermal analysis. I. INTRODUCTION M ORE than 150 years after the first electrical machine prototypes were introduced, electromechanical energy conversion remains closely linked with four main concepts: DC, synchronous, induction, or switched reluctance machines. Generally based on the use of laminated magnetic circuits, classical machine structures fundamentally lie on a two-dimen- sional magnetic flux circulation. Manufacturers of electrical machines with low cost and mass production applications are faced with economic realities that lead to structural choices. The main objectives were first to re- duce volume of materials used and manufacturing costs. To get good performance, progress in magnetic materials process man- ufacturing has been made in the last twenty years. We can cite in particular the use of high performance magnets in brushless motors which have replaced DC motors in most applications. Now, environmental features must be taken into account. In particular the features of recycling, which have an economic im- pact, cannot be ignored. If we consider the conventional struc- ture of machine with laminated steel and classical winding coil, recycling is quite difficult or impossible. Claw pole machines provide a solution to this dilemma. Those actuators which are based on simple concentric coils integrated in a preformed stator armature are now mounted with an automatic manufacturing process that significantly reduces the cost. This configuration allows one to easily dismantle the stator and collect the coils to recycle the copper. However, their efficiency remains relatively low compare with that of the permanent-magnet brushless machine [1], [2]. The emergence of new composite magnetic materials (plastic bonded magnets, soft magnetic composites) may radically modify this situation by enabling the development of innova- tive machine topologies. These materials are already used in the Manuscript received June 10, 2011; revised October 07, 2011, December 08, 2011; accepted December 12, 2011. Date of publication December 23, 2011; date of current version May 18, 2012. Corresponding author: C. Henaux (e-mail: Carole.henaux@laplace.univ-tlse.fr). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TMAG.2011.2181530 field of static conversion [3], and electromechanical actuation [4]–[8]. Their magnetic characteristics, such as the permeability and the saturation level and their tensile strength, are still lower than the laminated steel ones. But research studies carried out in chemical compound and manufacturing (thermal cycles, compression phase, etc.) allow for significant progress [32], [33]. Replacing in conventional laminated structures by soft magnetic composites with any change of the magnetic circuit cannot yet improve the performances. But those conveniences can be compensated by the diversity of the magnetic compos- ites manufacturing process (molding, injection or compression of massive pieces) which allows the definition of relatively sophisticated magnetic circuits making the flow of magnetic flux in three dimensions in nonconventional structures possible. In this paper, a new concept of machine made of composite magnetic materials is presented. This structure is devoted to a widespread domestic or automotive application. In Section II, the different composite magnetic materials used are studied, particularly their magnetic and thermal characteris- tics. The structure of the machine is then described from a tech- nological point of view in Section III. The experimental capabil- ities of the prototype are given in Section IV and compared with conventional solutions. Finally, Section V describes the conclu- sion and perspectives of the work. II. THE COMPOSITE MAGNETIC MATERIAL In the field of magnetic materials, the technology of compos- ites is subdivided into two main classes which respectively cor- respond to “passive” materials (Soft Magnetic Composites) or “active” materials (Plastic Bonded Magnets). A. The Soft Magnetic Composite—SMC SMC materials are basically iron powder particles separated with an electrically insulated coating. Those insulating particles can be pressed to form simple or complex magnetic parts. From a magnetic point of view, those compounds give the best of an interesting performance compromise in terms of magnetic sat- uration level and low eddy current losses. Moreover, they offer a 3-D flux carrying capability and a cost efficient production 0018-9464/$26.00 © 2011 IEEE