Underwater Contactless Power Transmission Based On Electromagnetic Induction

Power transmission for underwater mechanical and electrical equipments is evitable in deep-sea resource explorations. It generally relies on contact methods, which require complicated sealing in the hostile deep sea. However the connecter was always badly worn and was threaten by electrical leakage. The contactless power transmission technology is expected to resolve these problems because of its special advantages.Based on the electromagnetic induction, the CLPT system supply electrical energy for the equipments without any electrical connection between the power source and the loading. Comparing to the contact method, the contactless one has remarkable advantages, such as avoiding the danger of electrical shock and leakage without complicated sealing. Consequently, the key technologies of the CLPT system include the following:resolving the limited transferring power due to low coefficients, reducing the energy loss in seawater, maintaining the system's parameters which may be changed by the high pressure and stream in the deep sea, and some other problems such as the electromagnetic shielding and system's stability. These issues have been systematically considered in this thesis.The mutual model and magnetizing model have been established to analyze the system's transferring characters. And the influences of different compensations have been investigated to select a reasonable compensation structure for the system. In order to optimize the electromagnetic (EM) coupler's structure and the system's frequency, the eddy current field of the EM coupler in the seawater was modeled. Therefore the coupler's parameters, power losses and EM shielding were investigated by the finite element method (FEM). By using reluctance modeling method, the magnetic circuit of the coupler was modeled. Therefore, the parameters, such as magnetizing inductance and coupling coefficient, which can be changed by high pressure and stream in the deep sea, were explored to provide references for the system's stability analysis.As results of the above analysis, we designed the electric circuit and magnetic structures and the prototype the CLPT system for deep-sea applications. According to the electric characters and the physical structure of the EM coupler, power losses of the windings were modeled and the optimizing method for the winding turns was proposed. Finally, some experiments were implemented to verify the designed system, including the power transmissions in seawater and high pressure up to 40 MPa, and with misaligned cores and EM shielding. It demonstrated in the experiments that the optimized EM coupler is adaptable to the deep-sea environment, and the CLPT system is sufficient to supply electrical energy for underwater equipments with high efficiency.