Vector control of multiple-module transverse flux PM generator for large-scale direct-drive wind turbines

This paper proposes an efficient current control algorithm and a suitable power conversion system of a multiple-module transverse flux permanent magnet generator (MM-TFPMG) for large-scale direct-drive wind turbines. The MM-TFPMG is composed of multiple-module structures based on an independent three-phase configuration. In this paper, the single-phase current control applying the d-q transformation and the independent three-phase dqn-axes current control are proposed for the generator-side control of the MM-TFPMG. The control performance and characteristics of the single-phase dq-axes current control with a variable cutoff frequency and the independent three-phase dqn-axes current control using a concept of vector control are analyzed. As a result, the independent three-phase dqn-axes current control by using the vector control is an appropriate method to efficiently control the generator-side of the MM-TFPMG. The proposed algorithm is easily implemented and has less computation resource. Moreover, the control performance is better than the independent single-phase dq-axes current control despite the change of wind speed. The validity and usefulness of the proposed independent three-phase dqn-axes current control algorithm are verified and compared through several experimental results.