Online Diode Fault Detection in Rotating Rectifier of the Brushless Synchronous Starter Generator

The rotating rectifier in the brushless synchronous starter/generator is more vulnerable than others. Therefore, fault detection of the rotating rectifier is necessary. This article focuses on the identification of the diode failures in the rotating rectifier of the brushless synchronous starter/generator. Traditional approaches based on the analysis from the main exciter field current or main machine output voltage may lose the fault location information. To solve this problem, the fault features based on the rotor current are analyzed. With a simple rotor current restructuring approach, the magnitude ratio of second harmonic to fundamental obtained by bandpass filters on the restructured rotor current is employed to confirm the one diode open-circuit or one diode short-circuit fault. The experimental results verify the feasibility and effectiveness of the proposed method.

I. Introduction

With the development of more electric aircrafts, the integrated starter/generator (ISG) system based on a multistage brushless wound-rotor synchronous machine becomes more and more popular, owing to its high safety [1]. This ISG system consists of a pre-exciter (PE), a three-phase asynchronous main exciter (ME), a rotating rectifier (RR), and a main machine (MM) (see Fig. 1). Fig. 1.

Structure of starter/generator with three-phase brushless exciter.