Investigation of a doubly salient Halbach array linear permanent magnet machine for wave energy converters

In this paper a novel E-core Linear Variable Reluctance Vernier Hybrid Permanent Magnet (LVR-VHPM) machine with inherent magnetic gearing is proposed for use in the long stroke application of a wave energy converter. The proposed topology is a combination of a doubly salient flux reversal machine, a consequent pole machine and a surface mounted Halbach array Permanent Magnet (PM) machine. The stator teeth interact with horizontally and vertically magnetized PM and ferromagnetic poles in such a way as to maximize the flux density in the machine by minimizing flux leakage. The translator is segmented to ensure the most effective use of material for minimum mass. A performance comparison study between the novel LVR-VHPM machine, a baseline linear Vernier Hybrid Permanent Magnet (VHPM) machine, a linear Halbach VHPM machine and a linear Consequent pole VHPM machine is used to show that the best result is achieved by the combined topology. All four designs consist of the same double sided E-core stators, segmented translators and an equal magnet mass.