Design Of Digital Control Power Supply For Carbon Fiber Infrared Heating Drive

With the improvement of living standards,people have higher and higher demands on the living environment.More and more people pay attention to the problem of heating in winter.At present,the commonly used heating material is an electric heating wire,which has low heating efficiency and high power supply voltage,and has not undergone safety isolation,and has high safety risks.Carbon fiber as a new type of heating material has the characteristics of low voltage power supply,infrared radiation heating,high thermal efficiency,long life,energy saving and environmental protection,and strong plasticity.It gradually goes to the market.The power supply of the heater using carbon fiber as the heating material should have the characteristics of small size,low cost,long life and high efficiency.According to the comprehensive evaluation of the above requirements,LLC resonant converters have the advantages of simple structure,high efficiency,and zero voltage switching(ZVS)and zero current switching(ZCS)in the full load range.The main topology of the fully digital power supply for indoor carbon fiber heaters.In order to achieve the characteristics of high life and low cost that the heater power supply should have,this design does not use the PFC + LLC two-stage structure with a pre-stagePower Factor Correction(PFC)unit,but the AC mains After rectifying and filtering,it directly enters the LLC resonant converter,and uses a long-life polypropylene capacitor(CBB)at the input end to replace the electrolytic capacitor with limited life for filtering.In view of the problem of small capacitance value of CBB and large input voltage ripple after filtering,the design of the power supply uses Pulse Frequency Modulation(PFM)and Pulse Width Modulation in the control strategy(PWM)combined to achieve output voltage stability in the case of a wide input voltage range.This design also adds the Internet of Things function to the power supply to achieve intelligent control of the power supply.Firstly this thesis introduces the characteristics of carbon fiber materials,determines the main topology of LLC resonant converter as the power supply,and designs the power control section and the intelligent control section.Then through the analysis and modeling of the working process of the converter,the main circuit of the power supply is designed.The PWM + PFM control strategy was simulated and analyzed using Pspice software to verify the effectiveness of the control strategy,and the harmonics at the input and output were also analyzed.Finally,according to the power supply design and control algorithm simulation,a 100 W prototype was made using STM32F103C8T6 as the main control chip.The relevant waveforms and intelligent control parts were tested.The analysis of the waveforms verified the rationality of the control algorithm and circuit design.The measured output voltage ripple is 2V,which can meet the heater's requirement for voltage ripple,and the highest efficiency is 92.26%.