An energy retrieving device includes a first rectifier circuit, a direct current (DC) link circuit, a second rectifier circuit, an energy retrieving unit, a motor controller, and a micro control unit (MCU). The MCU includes an energy retrieving control module, to control the energy retrieving unit to work according to control of a processing module. The processing module detects whether a motor deceleration signal is generated by the motor, and controls the energy retrieving control module to make the energy retrieving unit retrieve power when the motor deceleration signal is generated by the motor.