Multi Model Analysis And Maximum Power Tracking For ICPT System

The Inductive Contactless Power Transmission system(ICPT system)uses a loosely coupled transformer for power transmission.The primary and secondary sides of the transformer are separated without physical contact.It is widely used in electric vehicles,satellite solar panels and other scenarios.At present,most of the research on ICPT systems is based on simulation or experimental results of transmission efficiency and output power.Most of the system operating point selection only considers the maximum output power.To this end,this paper analyzes the ICPT system under LCC/S compensation with multiple models,analyzes the magnetic field of the loosely coupled transformer,and proposes an improved disturbance observation method to realize the maximum power tracking of the wireless transmission system.Firstly,the mathematical model of the ICPT system under LCC/S compensation is constructed,the ICPT system is analyzed with multiple models,the relationship between the resonance frequency and the compensation component parameters is calculated,and the voltage gain is derived using characteristic parameters such as the quality factor in the circuit.Analytical formula for transmission efficiency.Secondly,the magnetic field of the single-turn toroidal current coil is analyzed,and its magnetic field distribution characteristics are obtained.On this basis,the two-dimensional and three-dimensional self-inductance and mutual inductance parameters of the primary and secondary coils of the loosely coupled transformer are calculated,and the influence of the coil size,core thickness and offset distance on the transformer parameters is explored.Thirdly,the maximum power tracking method of the ICPT system is improved,and the variable step length disturbance observation method is used to further improve the tracking speed and accuracy.When analyzing the data of the tracking process,it is found that the final tracked operating point voltage is not the maximum voltage in the tracking process.Therefore,referring to the tracking method of MPPT in the photovoltaic system,the hysteresis comparison method is introduced to solve this kind of oscillation problem.The combination of variable step length perturbation observation method and hysteresis comparison method solves the problem of tracking speed and accuracy cannot be balanced,and oscillation near the optimal operating point.Finally,the maximum power tracking experiment platform of the ICPT system was built to measure and calculate the parameters of the loosely coupled transformer under normal conditions and axial offset,and test the effect of the compensation component parameter drift on the output characteristics of the ICPT system,verifying the need for tracking the maximum power working point.