Sensorless Starting Control of the Brushless Synchronous Starter/Generator Based on Rotor Current Characteristics of the Main Exciter

The unique characteristics of the main exciter (ME) in the brushless synchronous starter/generator (BSSG) have been extensively studied to achieve sensorless starting control. However, the existing methods face drawbacks such as insufficient dynamic performance, complex demodulation processes, and estimation phase delays. In this article, the dynamic characteristics of ME rotor currents are analyzed and summarized quantitatively. Based on these characteristics, a novel sensorless starting control method is proposed. First, a position detection method of signal reconstruction is established. The rotor position can be derived from the complex dynamic features of estimated ME rotor currents. Meanwhile, a parameter estimation method for ME at a standstill is proposed by utilizing the current characteristic in the commutation interval. With this method, the stator parameters of ME can be estimated with a single α-axis voltage and current, removing the restriction of the commutation mode of rotating rectifier in ME parameter estimation. Finally, the sensorless starting control of BSSG is realized with the proposed methods.