Electric bicycle, control device and method thereof

The invention discloses an electric bicycle, a control device and a method thereof. The control device comprises a cell sensor module, a PWM (Pulse Width Modulation) control module and a motor drive module, wherein the cell sensor module is used for detecting cell power; the motor drive module is used for driving a motor; and the PWM control module comprises a first voltage judging unit, an accelerate starting unit, a current-limitation judging unit, an undervoltage judging unit and a PWM set-value regulating unit. The invention has the advantages that by reducing starting current and judgingthe voltage value of the cell power, when judging that the cell voltage dropping variation is greater than a threshold value, the increased proportion of current is reduced immediately, and the voltage drops into a normal range and is finally retained on an undervoltage point. The invention ensures that the electric bicycle can continually run in a state with slightly lower current, an endurance mileage is effectively increased, and cell deep discharge is avoided so that the cell life is prolonged at the same time.