Research On Electric Bicycle Timing System Of PWM Double Closed-loop Circuit

With the rapid development of modern social economy, the pace of people′s living isbecoming faster, the scope of activities continues to be expended, the demand of travel time isreduced as much as possible. Electric bicycle with the advantages of rapidity, convenience,environmental protection and economy meets common people′s requirments of quick travelfor short distance. The two jointly promote the rapid development of electric bicycle industryat home and abroad adding four core technology great progress.But the existing electric bicycle timing system is all open-loop control, there is nofunction of renewable generation feedback brake in the main circuit. Therefore, energyutilization rate is low and the dynamic performance is poor in the circuit system. This is badfor actual situation of frequent loading starting and braking, stepless timing of electric bicycle.Aiming at the shortages of the existing open-loop control and main circuit, considering goodstarting and timing performance of speed, current double closed-loop timing system and thefeature of the irreversible PWM converter with braking current path, combining the theory ofdouble closed-loop timing and PWM chopping control, to research and design PWM speed,current double closed-loop electric bicycle timing system to enhance static and dynamicperformance, improve starting performance to be adaptive to frequent loading start of electricbicycle; to advanc energy utilization rate from storage battery conservation and increas tripmileage. The existing open-loop speed timing system is transformed into closed-loop timingsystem and the dynamic performance of the system is corrected using speed adjustor ASR andcurrent adjustor ACR to satisfy the requirements of stability, accuracy and rapidity of theauto-control system. The paper sets up the dynamic mathes model of PWM doubleclosed-loop timing system of the electric bicycle according to the mathes model of DC motorand the power electronic converter mathes model. Studying the design method of ASR, ACRtwo adjustors according to mathes model.ASR, ACR two adjustors are one of key points of double closed-loop timing systemdesign. The paper discusses in detail engineering realization method of two adjustors usingtheory and method of engineering design, and studies main circuit with the function ofrenewable generation feedback brake and every control circuit unit and their design method,including PWM generation circuit, drive circuit, under voltage protection circuit, currentprotection circuit etc. To simulate every circuit unit using Protues testing rationality andcorrection of design. Finally the whole timing system results of simulation are obtained usingMATLAB and the results are close to ideal situation, it shows that dynamic performance isconsistent with design and meets performance index of design requirments.