In order to gain the high performance of the injustrial motor drive, most of the industrial drive system have PI controllers in the current control and speed control for tuning process [1]. The Ziegler-Nichols methods which are based on the empirical research of try and error, are commonly used to design the industrial speed drive. However, the overshoot phenomenon of the system could occur if the delay time is not sufficient to determine the spped controler paramenters [2]. A modification of Ziegler-Nichols methods based on Bode’s frequency diagram is addressed and proved to reduce the overshoot [3]. This method is complicated and is not easy to determine the rotor operating frequency. With the approximation of current control loop by considering the operating rotor frequency, the speed control system can reduce to the first order system. The crossover frequency of current controller and the 3-dB corner frequency of PI controller can be found with proper selection of time delays of both current and speed controllers, respectively. The rotor frequency is designed in the range between these two frequencies for proper operation. The simple method to determine the range of operating speed with appropriately tuning controller parameters, can not only
speed up the design and implementation of speed controlled motor drive but also reduce the development time. The electric bicycle which does not produce the exhaust gas and generate the air pollution has become one of the most efficient and economic traffic vehicles in the metropolitan city [1]. Recent years, due to the highly development of power electronic devices and microcontrollers, the design and implementation of the electric bicycle have been studied in the academic field and widely applied to the industry as well. In order to realize the complete system, the basic configuration of an electric bicycle drive which consists of a controller, battery charger, battery and electric motor is firstly addressed in this paper. A controller is basically based on a microcontroller that controls the power from the battery to the electric motor and the auxiliary devices such as the brake, the signal lights as well. Therefore, in order to design and implement an electric bicycle with speed control, a brushless dc motor drive based on a microcontroller is presented in this paper. Both design criterion and requirements of the designed system meet the standard of electric-auxiliary bicycles CNS14126 in Taiwan