| In recent years,the new energy vehicles with advantages in energy saving and environmental protection have experienced explosive growth.Nowadays,it mainly transfers energy through the charging method connected by wires.This charging method has a defect that the device is aging easily,and there is a danger of electric shock.The emergence of wireless charging not only solves the above problems effectively,but also solves the problems of plug-in sparks and wear caused by wired charging.It has a very broad development space and application prospects.The parameters of the electromagnetic coupling coil are optimized by Maxwell simulation software.The optimized coupling coil is combined with the bilateral LCC compensation topology to realize the frequency conversion control of the wireless charging system to maintain the relatively high transmission efficiency of the system.First of all,with the aim of improving the versatility and transmission efficiency of electromagnetic coupling coils,a wide-frequency electromagnetic coupling coil is proposed and designed to study the key parameters of the electromagnetic coupling coil at different charging frequencies.The wireless charging system with electromagnetic coupling coil as the core mechanism is mainly responsible for the transmission and reception of energy.Therefore,the structure of the coupling coil and the optimized design of the parameters will directly affect the performance of the wireless charging system.Through the Maxwell simulation software to establish the coupled coil model,there are factors such as no core,core thickness,coil inner diameter,transmission distance,coil lateral offset and frequency offset to optimize the coil model.The parameter-optimized electromagnetic coupling coil has certain characteristics of antioffset and wide frequency,which provides a basis for the design of the next wireless charging crossover control system.Secondly,the scheme of PFM and PI is proposed to realize variable frequency control strategies at different stages to improve charging efficiency.The energy transmission method of the system is to use the resonance principle,which is to realize the energy transmission through the resonance principle of two transmission coils at the same resonance frequency.The research analyzes the constant current and constant voltage output characteristics of the bilateral LCC compensation topology,the equivalent model of the battery and the charging method.For the wireless charging system composed of bilateral LCC compensation topology,wide frequency electromagnetic coupling coil and frequency conversion control strategy,frequency conversion charging control is realized in a two-stage charging mode.It is verified through simulation that the system operating frequency is adjusted to achieve the transition from CC to CV charging mode.Finally,the overall design of the electric vehicle wireless charging system was designed,including the electromagnetic coupling coil in the main circuit,the full-bridge inverter and so on.At the same time,the control circuit with DSP as the control core is also studied.Its main functions include driving,sampling,conditioning and protection.It is verified that the designed wireless charging system can achieve frequency conversion control to achieve the goal of higher transmission efficiency through the built experimental platform and comparative analysis. |
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