| Compared with traditional wire power transmission,wireless power transmission has the characteristics of safety,flexibility and durability,and is widely used in people’s daily life and industrial production.However,at present,wireless power transmission is mostly used in lowpower short-distance transmission,and there are few researches on complex application scenarios of medium-power and long-distance,and there is a technical gap for automatic tuning of wireless charging systems while achieving regulated output.This article takes the design of magnetic coupling resonant wireless charging system and its control strategy as the research object,focuses on the energy transmission characteristics of the system,hardware circuit system and software control strategy,and designs that can cope with various complex working conditions and different media complexities.The environmental wireless charging prototype realizes automatic system tuning while ensuring stable supply of load charging with high transmission characteristics.The main research contents of the thesis are as follows:(1)Use the equivalent circuit theory to establish a mathematical model of the wireless charging system,analyze the energy transmission characteristics of the system,and optimize the design of the electromagnetic coil.After analyzing the working characteristics of the four basic compensation topologies,focus on comparing the two structures of series-series and series-parallel,using the control variable method to analyze the influence of the system operating frequency,coupling coefficient,load resistance and other factors on the system transmission characteristics,and comprehensively consider the selection of series-parallel Resonance compensation topology;using Maxwell electromagnetic simulation software to model and simulate the coil,optimize the design of the transmitting and receiving coils in terms of coil shape,magnetic core structure and wire parameters,and the designed coil quality factor reaches 623.39 to achieve system transmission Energy efficient wireless transmission from end to receiving end.(2)Aiming at the problem of excessive system volume caused by the separation of resonance compensation and inverter circuit,a half-bridge inverter resonance circuit is designed.The coil inductance compensation capacitor is used as the back-stage capacitor of the inverter circuit,which effectively simplifies the hardware circuit,and realizes the efficient conversion of system power while reducing the difficulty of circuit control.Circuit simulation and experimental testing are used to verify the rationality of its design.(3)Analyze the detuning mechanism of the wireless charging system,and study the strategies of automatic tuning and regulated output.The transmitter adopts frequency tracking technology based on digital phase-locked loop to realize automatic system tuning;the receiver adds a PID controller to ensure stable load output.For the problem of PID controller parameters difficult to tune,particle swarm intelligent algorithm is added based on its characteristics such as accurate and fast optimization.,To realize the self-tuning of PID controller parameters,compared with the traditional controller,the steady-state performance of the system is greatly improved,the adjustment time is reduced by 0.65 s,the steady-state error is reduced by 1.04%,and the stable output of the system is ensured.(4)Construct a multi-scenario application experiment platform for the MCR-WCT system.The circuit waveform,signal sampling accuracy and communication quality of the designed wireless charging prototype were tested,the output characteristics of the system under different working conditions were studied,and the prototype automatic tuning strategy and voltagestabilized output strategy were experimentally verified.Analyzing the output characteristics of the MCR-WCT system prototype in different media environments such as foam,wood,ceramic tiles and water,experiments show that the maximum output power of the wireless charging prototype can be stabilized above 1k W under different media environments,and the transmission efficiency is as high as 90%,indicating The system can adapt to complex environments to achieve high power and stable output,which has great practical value. |
PDF Full Text Request