Sensorless Starting Control of the Brushless Synchronous Starter/Generator Based on Flux and Parameter Estimation of the Main Exciter

Using the main exciter (ME) as the quasi-resolver is an emerging advanced sensorless control technology. Since the ME becomes a dual-use machine, the structure of a brushless synchronous starter/generator (BSSG) is simplified and more compact. However, the existing rotor position estimation methods in this path are limited to the low-speed range. What is more, the acquisition of the stator parameters of ME is still tedious due to the special structure of BSSG. In this article, a sensorless starting control method of BSSG based on flux and parameter estimation of ME is proposed. First, the relationship between the rotor position and flux is strictly derived, and the low-speed limitation has been removed theoretically. According to this relationship, the rotor position estimation methods of ME and the main generator are then proposed. Besides, taking advantage of the nonlinear operating characteristics of the rotating rectifier, a simple parameter estimation method of ME is proposed. With this method, the stator parameters of ME are estimated with only stator voltages and currents by the recursive least squares algorithm, and rotation is not needed. Finally, the effectiveness of both the sensorless starting control method and the parameter estimation method is verified by experiments.