Study On Soft-switch Technology For ICPT System Under The Condition Of Changing Temperature

Inductive coupled power transfer(ICPT) technology is a new kind of power transmission technology which is comprehensive utilization of modern Power electronics technology, magnetic coupling technology, modern control theory, and high power electric energy conversion technology with high frequency. The traditional electric contact is avoided in ICPT system since using magnetic field as electricity transmission medium, which makes it has the advantage of safety and flexible between the power supply and electrical equipment. This technology has been widely developed and applied in recent years.There is an air gap between the primary coil and secondary coil in ICPT system, so the high frequency resonant mode is used for improve the efficiency of energy transmission. In this case, the soft switching resonant converter has become a common form of main circuit in ICPT system. In some special circumstances, especially under the condition of high temperature, the system parameters will change along with the change of temperature. The change of system parameters will lead to the shift of resonant frequency, which will reduce the efficiency of energy transfer, increase the stress of the switch devices, and make the system unstable.According to the application background of oil drilling rig, the harmonic of SS, SP, and SN type topology are analyzed with the Fourier transform. The SN type topology is chosen as the main circuit topology in this paper. The high temperature box is used to simulate the actual operating temperature, and then the main parameters which will affect the operation state of soft switching are measured and analyzed, the characteristics of main parameters with the change of temperature can be got ultimately. The model of SN type topology is established with the stroboscopic map modeling method and the cycle of the fixed point theory, the relationship between the resonance frequency of the system and the change of temperature are built in this paper, which can be used as the basis of realizing soft switching of the system by adjusting the driving frequency. A method combined with look-up table method and disturbance observation is designed by studying the soft switching control method of ICPT system. This method can be used to reduce the devices which are influenced by the changing of temperature and ensure that the soft switching in ICPT system can work at a wide range of temperature. The feasibility and validity of this scheme are verified by building Matlab Simulink model and simulation. The main circuit, drive circuit, and soft switching control circuit are designed and the main components are chosen as well after that. The experimental platform is built based on the theoretical analysis, simulation results and designed circuits. It is verified that the control method proposed in this paper can realize the soft switching operation well in practical system with a wide range of temperature.