Patent ID: 9537434
Date: 2017-01-03
CPC Classifications: F04D,H02M,H02P

Claim:
1. A DC electric fan receiving a first direct current voltage, comprising: a motor directly driven by the first direct current voltage; a fan blade connected to the motor and rotated by the driving of the motor; a voltage converting device to receive and convert the first direct current voltages to a second direct current voltage, wherein the voltage converting device comprises a voltage sensor, a pulse width modulation control circuit and a switch, the voltage sensor transmits a sensing voltage value to the pulse width modulation control circuit, the pulse width modulation control circuit controls the switch to make the voltage converting device output the second direct current voltage according to the sensing voltage value, and the magnitude of the first direct current voltages is larger than the magnitude of the second direct current voltage; and a motor controller receiving the second direct current voltages to control a rotation direction of the motor, wherein the motor controller is not powered by the first direct current voltage and the first direct current voltage is a fixed direct current voltage.