High-Frequency Voltage Injection-Based Fault Detection of a Rotating Rectifier for a Wound-Rotor Synchronous Starter/Generator in the Stationary State

Fault detection of a rotating rectifier for a wound-rotor synchronous starter/generator (WRSSG) without a rotor position sensor in the stationary state is necessary for a successful engine start. Based on high-frequency (HF) voltage injection, a novel fault detection method of the rotating rectifier for the WRSSG in the stationary state is proposed. The rotating HF voltage is imposed on the stator windings of the main machine, and the HF feature current signal extracted on the stator windings of the main exciter is used for fault detection. In this article, the HF current signal in the main exciter with the rotating rectifier under different working conditions is analyzed first. To obtain the HF response current on the stator windings of the main exciter, the HF model of the WRSSG is analyzed. Through the Fourier series, the HF feature current signal together with fault detection is achieved. Compared with the existing fault detection methods, the proposed method shows no dependency on the rotor position information. Experimental results verify the feasibility and effectiveness of this method.

I. Introduction

With the rapid development of more electric aircraft, the wound-rotor synchronous starter/generator (WRSSG) has become the perfect candidate to become an integrated starter/generator due to its high safety and low maintenance cost [1], [2]. Furthermore, there is no position sensor installed for the WRSSG studied in this article since sensorless control for the WRSSG has become an inevitable trend and choice [3]–[5]. Fig. 1 shows the typical structure of the WRSSG, which consists of the pre-exciter (PE), the main exciter (ME), the rotating rectifier, and the main machine (MM). The PE is a permanent magnet generator, and an electrically excited wound-rotor synchronous machine serves as the MM. The ME is a rotating-armature electrically excited synchronous machine with three-phase stator windings. The rotating rectifier is a typical three-phase diode rectifier that is adopted to achieve a brushless structure.