Virtual Moment of Inertia-Based Independent Dual-Speed Regulation of Brushless Dual Rotor Machines

Brushless dual rotor machines (BLDRMs) are emerging as a promising solution for applications requiring multiple energy flows due to their dual electric ports and dual mechanical ports. For counter-rotating propellers in underwater and aerial vehicles, achieving independent dual-speed control is essential. However, the dual-inertia characteristic of BLDRMs makes it difficult to directly apply speed controller tuning methods developed for the single-inertia machines. Besides, the inherent coupling between speed and torque in dual rotors can further degrade control performance. In this paper, the concept of virtual moment of inertia (VMI) is first proposed based on the electromechanical models, enabling the BLDRMs to be equivalently transformed into conventional single-inertia machines. Building on VMI, a model compensation-based active disturbance rejection control (MC-ADRC) strategy is proposed to further decouple and achieve independent speed regulation. Specifically, state equations are derived based on the outer rotor speed and the speed difference between the dual rotors, treating torque coupling as a lumped disturbance. Comprehensive details regarding the controller design and parameter selection criteria are provided to ensure the practical implementation of various types of BLDRM structures and certain other multi-port machines. Finally, experiments are conducted on a BLDRM drive platform to validate the effectiveness of the proposed method.