Research And Design On BLDC Control System For Electric Bicycle

With the conveniency and practicability of electric bicycles, people select to use it for short-distance travel. Compared with the early use of dc motor drive electric bicycle,we now adopt brushless dc motor drive. Electric bicycle has been effectively improved its comfort and operability, but not that much when it comes to mileage and cruising ability. How to improve the battery life is a hotspot of research on the industry, so the research on electric bicycle energy feedback and improving the battery life is of great practical application value and great theory significance. The main research work is as follows:The history and research status of related control technology of electric bicycles were introduced in the paper, which emphatically analyzed the research status of energy feedback control technology, then the structure characteristics, operation principle and mathematical model of brushless dc motor were reviewed.Electric bicycle braking energy feedback was studied, and the basic principles of brushless dc motor energy feedback was also analyzed. The text also analyzed and compared the process of regenerative braking and the mathematical model between half-bridge and full-bridge chopper modulation, then an electric bicycle control strategy of regenerative braking energy based on half-bridge chopper was put forward.Hardware circuit was designed including:A DSP minimum system circuit, power circuit, power inverter circuit, inverter drive circuit, current detection circuit, over current and voltage protection circuit, PWM phase protection circuit, signal processing circuit, isolating filter circuit, led display circuit, and etc. In software design, I also completed procedures like position signal acquisition, motor control, energy feedback control, speed calculating, speed PI close-loop adjustment, undervoltage and overcurrent protection and display program etc. An electric bicycle experiment platform which took the TMS320F2812as the core has been set up, I get the test conclusion that the designed electric bicycle controlling system can well control the electric bicycles, and it shows a good stability, moreover, it can effectively improve the battery life of electric bicycle.