Electric power assisted bicycle

摘要

To cause, when the capacity of a secondary battery for generation of an assisting force (assisting force) drops (the voltage drops), a driver to physically feel it as a variation in driving feeling that the remaining capacity has reduced and charging is required by intentionally varying the assisting force to assist driving by human power. A voltage drop detection means 112 compares data 113a obtained by A/D conversion of the voltage of a battery B with reference voltages VTH1 and VTH2 set in advance and outputs voltage drop detection signals 114a and 114b. When supply of the voltage drop detection signals 114a and 114b is received, assisting force variation control means 111 outputs a variation assisting force HA obtained by reducing or varying an assisting force A calculated by assisting force calculation means 103 almost to zero. PWM signal production means 104 produces and outputs a PWM signal 104a in response to the assisting force A or the variation assisting force HA to drive a motor 21 by PWM driving. <MATH>