ENERGY-EFFICIENT ELECTRIC DRIVE FOR TURBOMACHINERY BASED ON A BRUSHLESS MOTOR WITH AC EXCITATION

This study is dedicated to analyzing the electromechanical properties of brushless motors (BM) with AC excitation for application in electric drives (ED) of turbomachinery (fans, pumps, turbo compressors). Since such mechanisms consume approximately 25% of industrial electricity, optimizing their ED is a critically important task. A BM topology is proposed to eliminate the issue of missing machine-side commutation of inverter switches at low frequencies and during startup. A mathematical analysis of BM characteristics has been conducted, specifically investigating the optimal excitation frequency that ensures minimal power conversion in the rotor and stator. It has been shown that at an excitation frequency of 4–6 Hz, the total power of the converters decreases by 15–20% compared to conventional doubly fed schemes. Additionally, it is demonstrated that reversing the direction of the excitation field rotation allows for an extended speed regulation range, enhancing the system’s adaptability to variable operating conditions. The obtained results highlight the advantages of the proposed approach, including reduced thermal losses, increased overload capacity of the ED, and the elimination of the need for a rotor position sensor. The proposed solutions can be utilized in the development of high-efficiency control systems for turbomachinery.