A low-speed linear harmonic generator for grid-tied and stand-alone operation using hybrid excitation topology

Abstract

Since intermediate mechanical conversion mechanisms for speed, torque and motion conversion can be entirely eliminated, the direct-drive wave power generation attracts more and more attention [1]. Among various proposed generators, the permanent-magnet (PM) vernier generator is considered as a viable solution for the wave energy harvesting. This generator can efficiently harness this low-speed and high-power energy source via a so-called vernier effect by utilizing the effective harmonic magnetic field [2]. However, since only PMs are engaged for field excitation and the harmonic magnetic field is adopted, it is incapable to provide a flexible voltage control and power factor improvement. Moreover, the voltage regulation is incredible high. The purpose of this paper is to design a linear harmonic generator for producing electricity in a wave farm. Except for the PM excitation, the proposed generator is equipped with a set of DC field winding for the hybrid excitation. With this merit, the proposed generator exhibits a satisfactory performance for voltage regulation and power factor improvement which is desirable for both grid-tied and stand-alone operation [3]. © 2015 IEEE.