Design, control and applications of novel dual-mechanical-port electrical machines

Abstract

In this thesis, the design, control and applications of the novel dual-mechanical-ports electrical machines (DMPEM) are introduced. DMPEM is increasing investigated in recent years and has many industrial applications, including driving system of the hybrid electrical vehicle (HEV) and dual rotor generators for wind power generation. A novel DMPEM named as dual-rotor bidirectional-flux-modulation (DR-BFM) machine utilizes flux modulation effect which is to get rid of the brush and slip rings is proposed and studied. The brushless structure brings some prominent advantages, such as low cost and high reliability. Due to flux modulation effect, the operation principle of the DR-BFM machine is different from conventional DMPEM. Based on analytical model, the design and operation principle of the DR-BFM machine is studied. Furthermore, the dynamic model is also built to design the control strategy of the DRBFM. The major contribution of the thesis including: (1) the analytical model of the DR-BFM is firstly proposed using flux modulation theory. (2) The dynamic model of the DR-BFM for control strategy is built up. (3) The multilevel optimization method based on sensitivity analysis of the DR-BFM is presented. (4) Dual rotor field oriented control (FOC) for the DR-BFM is proposed and applied on the prototypes. (5) The dual rotor sensorless control of the DR-BFM machine is studied. (6) The dual rotors maximum power point tracking control for wind power generation has been presented and applied on one of the prototype. The mainly work of this thesis can be summarized as following: 1) A review of the DMPEMs and flux modulation machines. DMPEM includes induction dual rotor machine (IDRM), permanent magnet dual rotor machine (PMDRM), switched reluctance dual rotor machine (SRDRM) and flux-switching DC (FSDC) machine. Flux modulation machine is derived from the harmonic magnetic gear and employs flux modulation effect. 2) Flux modulation theory is illustrated using analytical model. The design and optimization principles are concluded. The dynamic model of DR-BFM machine in the synchronous reference frame is built for the dual rotor field orientation control of the machine. 3) The optimization design of a prototype of DR-BFM machine is presented. The effective optimization methodology combining genetic algorithm and finite element method (GA-FEM) is presented. Using the sensitivity analysis, the number of the optimization parameters is reduced. Computational cost of the GA-FEM optimization is decreased dramatically. 4) Control strategy of the DR-BFM machine is studied. The decoupling control of two windings is presented and verified by the simulation results. Using dual sliding mode observers, the dual rotor sensorless control of the DR-BFM machine is proposed. The estimated precision of the rotor position is accurate enough for the field oriented control (FOC) of both rotors. 5) Based on the optimization design, two prototypes with different pole-pair combinations are manufactured. A test bench is built for DR-BFM machine experiments. The controller including a control board system based on a TMS320F28335 DSP and a back-to-back inverter is designed. The operation performance of prototypes is presented. The experimental results are in excellent agreement with the theoretical studies and verify the effectiveness of the analytical model, optimization design methodology and the control strategy.