Calculating method of rotary speed of fan in power battery for hybrid electric vehicle

The invention provides a calculating method of the rotary speed of a fan in a power battery for a hybrid electric vehicle. A fan with LFm shift is adopted, wherein m is an integer from 0-7, and the larger the m value is, the higher the shift of the fan is; at a certain moment, firstly, the comprehensive fan shift at the moment is obtained according to the temperature change of a battery pack in a vehicle; the maximum fan shift corresponding to the vehicle speed at the moment is obtained according to different vehicle speeds; then, the minimum value in the comprehensive fan shift and the maximum fan shift corresponding to the vehicle speed is taken as the last fan shift at the moment; finally, the duty ratio relationship of the last fan shift and the pulse width modulating wave is converted into corresponding duty ratio of the pulse width modulating wave, and the rotation speed of the fan at the moment can be controlled by controlling a fan operation control port. According to the method, the rotation speed of the fan can be dynamically controlled.