| With the development of modern science and technology,mobile electrical and electronic equipment appear more and more frequently in people’s work and life,the demand for portable mobile power is also increasing rapidly,and the design of a digital portable power supply with high performance,small size and full function has great research significance for solving the problem of power supply in outdoor sports and emergency situations.For commonly used small electrical and electronic products,this paper designs a portable power bank system that meets multiple charging methods,diversified discharge output interfaces and real-time observation of operating status.Based on the energy storage characteristics of lithium batteries,the system designs a charging module with a wide range of voltage input for commonly used charging equipment,such as adapter charging(12.6V),photovoltaic panel charging(6-24V),car charging(12V),etc.,to charge lithium battery packs;For commonly used electrical equipment,a variety of output interfaces are designed,and the electric energy of the lithium battery pack is provided to the load through the DC discharge module and the AC discharge module;At the same time,the power management module is designed to monitor and display the operating status of the whole system in real time.This article will design a complete mobile power system from three parts:In the first section,it aims to design the power management module:using single-chip ARM chip to collect the voltage and current signals of each module,the signal processing through the driver chip data information in the LCD screen interface display,you can understand the system’s operating condition in real time.Through the control button,you can also control the whole system’s switch.The second part is to design system charging module: in order to meet the wide range of DC charging voltage input requirements,the use of FSBB converter,the use of PWM modulation technology.In the traditional two-mode control strategy to improve,the design adds the third Buck-Boost mode to smooth the transition,avoid the conversion blind zone caused by mutual jump in dual modes,and make sure the input voltage’s and output voltage’s wide ranges are stable.The third part is to design the system discharge module: In order to meet the power needs of commonly used electrical and electronic equipment,the system discharge module includes DC discharge and AC discharge.The DC discharge module adopts Buck-Boost converter to boost and step down the battery voltage,and uses USB charging technology to meet various interface requirements of different loads;AC discharge module uses push-pull boost,full-bridge inverter technology to output the battery voltage to the load with power frequency AC voltage,so as to satisfy the system output voltage,frequency accuracy,fast dynamic response to load changes control purpose,in the conventional PID double closed-loop control strategy to add fuzzy control,the control effect is improved.The results of the experiment indicate that the power management module can explicitly observe the operating status of the system in real time.The system charging module can charge the lithium battery pack in the voltage range of 8-24 V,and the voltage regulation accuracy of the output voltage is less than 1.7% during the instantaneous change of the input voltage;The AC voltage amplitude deviation of the system discharge module is +3%,-4%,the frequency deviation is ±0.2Hz,and the total harmonic distortion rate is less than 3%.Experiments show that the control strategy studied in this paper is practical and effective,and the operation performance of the power prototype is superior,which meets the expected goals. |
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