Research On Modeling And Control Of Magnetic Coupling Resonant Wireless Charging System In Medium Power

With the development of clean,low-carbon,safe and efficient energy system,energy technology is undergoing innovation in all aspects,among which wireless charging technology has become a research hotspot due to its safety,portability and reliability.The medium-power wireless charging market is gradually expanding and has considerable development potential,while the specific research is relatively rare.According to the power requirement,magnetic coupling resonant wireless charging technology has higher efficiency and longer distance than other wireless transmission methods.In this paper,the magnetic coupling resonant wireless charging system in medium power is taken as the research object,and the energy transmission characteristics,hardware circuit design,control strategy and other issues are studied.Finally,a wireless charging prototype with the adjustable output power was developed,and an experimental platform was built to test the performance of the prototype.The main research contents of this paper are as follows.(1)The energy transmission characteristics of wireless charging technology were studied,comparing the load power and transmission efficiency of series-series resonance and seriesparallel resonance.It was showed that series-parallel resonance could transmit higher energy without frequency splitting.Furthermore,a parameter optimization algorithm based on improved artificial bee colony was proposed,which could improve the convergence speed and target precision.By converting the parameter design requirement into a multi-goal optimization model,the optimal solution could be obtained using the improved artificial bee colony algorithm.(2)The hardware circuit of the wireless charging system was studied,and the half-bridge LCC resonant inverter circuit was designed,which worked in the quasi-resonant soft-switching state and thus had lower switching loss.The LC series resonance equivalent circuit was established,and the equivalent square-wave output power of the half-bridge inverter was obtained.The feasibility of modal analysis and equivalent modeling was verified by Simulink simulation and experiment,and the system mathematical modeling and output control would be simplified using an equivalent model.(3)The control strategy for the wireless charging system was studied,putting forward the PSO-BP neural network self-tuning PID algorithm to adjust output current,which used particle swarm to optimize the initial state of BP neural network.Through comparing different algorithms to adjust output current in Simulink simulation,the PSO-BP algorithm has the overshoot of only 3.1% and the adjustment time of 0.121 ms in step response,indicating that the dynamic and static performances of the wireless charging system were improved.(4)A medium-power magnetic coupling resonant wireless charging prototype was developed,and an experimental platform was built for performance experiments,testing the key signal waveform,signal sampling accuracy,2.4 GHz wireless communication,and energy transmission characteristics.The results showed that the signal sampling accuracy was high,and the error decreased with the increase of the signal.2.4 GHz wireless communication was of high quality,and the bit error rate within 200 cm was less than 1%.The prototype built on the optimal parameter had the highest output power of 1000 W and the maximum transmission efficiency of 84.79%,with the maximum transmission distance of 100 mm.With the output current adjustable,all the performances of the wireless charging prototype met the requirements,which showed that the energy transmission modeling,parameter optimization design,hardware circuit design and control strategy optimization were feasible.