Different approaches to reduce shaft voltage in AC generators

Abstract

This paper presents several shaft voltage reduction techniques for doubly-fed induction generators in\ud wind turbine applications. These techniques includes: pulse width modulated voltage without zero\ud vectors, multi-level inverters with proper PWM strategy, better generator design to minimize effective\ud capacitive couplings in shaft voltage, active common-mode filter, reducing dc-link voltage and\ud increasing modulation index. These methods have been verified with mathematical analysis and\ud simulations