Analysis of Electromagnetic Loss and Excitation Source Characteristic of an Outer Rotor-Type Permanent Magnet Synchronous Generator for Wave Power Generation to Breakwater

Abstract

In this study, we comprehensively compare and analyze research results on cogging torque, torque ripple, back electromotive force (EMF), and electromagnetic excitation sources according to the pole/slot combinations of permanent magnet synchronous generators (PMSGs). Each electromagnetic characteristic and design variable affects the generator's performance, and their impacts are assessed. Specifically, we analyze the pros and cons of each combination and suggest the optimal pole/slot combination.

Additionally, we present a method for analyzing the loss characteristics of a breakwater-linked PMSG for wave power generation using finite element analysis (FEA) and the Steinmetz equation for the proposed pole/slot combination PMSG. In renewable energy, generator efficiency is crucial and is significantly affected by core losses. Therefore, more accurate loss prediction is essential. The proposed method includes an abnormal eddy current loss coefficient in the existing Steinmetz method to enhance accuracy. The reliability of the loss characteristic analysis using the proposed Steinmetz method was verified through comparison with FEA results.

The analysis method presented in this paper can be useful in evaluating the core loss characteristics of generators or motors.