Design and Optimization of an Integrated Generator-Rectifier System for Offshore Wind Turbines

Abstract

Many modern direct-drive wind generators at high power levels adopt permanent magnet synchronous generators (PMSGs). Typically, these PMSGs are coupled with fully rated active rectifiers to process and deliver power to the main grid. However, the limited-speed nature of a wind turbine creates an opportunity to reduce the amount of active rectification required, which in turn would reduce the cost of the drive and improve system reliability. This paper presents a design and optimization process of a direct-drive PMSG coupled to an integrated generator-rectifier system. In order to make the hybrid architecture possible, a multi-port generator is designed with multiple diode rectifiers and a single active rectifier. This paper describes a process for a 10 MW generator-drive optimization under the proposed architecture with two different implementation methods. These implementations are compared using optimal Pareto front from a system-level efficiency-weight perspective.