Double d-q Axes Control of Transgenerator-Flywheel System for Wind Power Generation and Energy Storage

The authors proposed a transgenerator-flywheel system for wind power generation and storage in a previous paper. The transgenerator is a three-member dual-mechanical-shaft (DMS) electric machine consisting of a wound stator, a permanent magnet (PM) rotor, and a wound rotor. Due to the structural and control complexity of the transgenerator, the double d-q axes-based field-oriented control (FOC) is applied to control the two rotors independently for different purposes. This paper reviews the proposed transgenerator-flywheel system and illustrates how the control references of the current components are calculated using double d-q axes. Simulations are performed in MATLAB/ Simulink to verify the independent control of the two rotors and evaluate the control performance. Results show that with the double d-q axes, the inner and outer rotors can be controlled independently with accurate and fast control response.