Design And Research On Electronic Throttle Control System Of The Extended-range Electric Motorcycle

China is the largest motorcycle producer and consumer of all over the world, motorcycle occupies an important position in our country’s transportation. In recent years, influenced by the national policy encouragement and the ideas of energy conservation and emission reduction, the electric motorcycle industry is developing rapidly, but at present, the users are seriously affected by problems such as short mileage and short battery life of electric motorcycle. An Extended-Range Electric Motorcycle is composed of an auxiliary power unit(APU) and an electric motorcycle, it reduces the requirement of battery capacity, thus eliminate the ‘range anxiety’ of the consumers, and have the advantages of traditional motorcycle and electric motorcycle, it is one of the best solutions to increase the mileage of current electric motorcycles.At present, most of the APU of Range-extended electric motorcycle adopt mechanical speed regulating system, keeping the speed of engine at a steady value, causing a large output loss, high fuel consumption of engine and reducing battery life at light load; however, cannot fully meet the power requirements at heavy load. Therefore, an optimal improved design for existing range-extender is made in this paper, and an electronic throttle control system is designed to replace the original mechanical speed control system, the range-extender can automatically control the output voltage of the generator according to vehicle load to meet the needs of vehicle power, while ensuring the safety of power battery charging and extending its life at the same time.This paper established a mathematical model of APU including engine and permanent magnet synchronous motor, and the whole model is modeled and simulated by PID control algorithm in MATLAB/Simulink tool, the simulation results show that the actual output voltage can quickly follow the target voltage, and the steady-state error is small, the correctness of the model and the feasibility of the control strategy are verified by simulation. On the basis of theoretical analysis, the paper completed the design of hardware and software to meet the functional requirements. For the hardware designing, using 16 bit PIC microcontroller as the main control chip, using the stepping motor as actuator to adjust throttle opening; for the software design, complete the main program, interrupt and failure program based on the C language.The test results show that the electronic throttle control system can automatically control the throttle opening, the engine speed and the output voltage of the generator according to the load of the motorcycle. During a certain engine speed range of 2400r/min ~ 3582/min, the system can increase engine speed with an increasing load; the output voltage of the generator increases with an increasing motor load among 60 V ~ 70 V. Therefore effectively improve the economy, power, and reduce the noise and fuel consumption at light load, improve the dynamic performance of heavy load, at the same time, keep the charging voltage of the batter y pack within a reasonable range, achieve the purpose of energy saving, noise reducing and battery protecting.