Power distribution method for electric vehicle driven by two power sources

摘要

A power distribution method for electric vehicle driven by two power sources includes executing a first power distribution law by a vehicle control unit, wherein the first power distribution law sets a distribution ratio according to a vehicle speed of the electric vehicle, a torque demand, and a current gear of a transmission. The powers outputted by first and second motors are adjusted according to the distribution ratio such that the first and second motors can operate at the most efficient operation points to increase the operational efficiency of the electric vehicle driven by two power sources.

主权项

1. A power distribution method for an electric vehicle driven by two power sources comprising:
driving a first motor and a second motor to run respectively by a vehicle control unit, with the first and second motors simultaneously outputting powers to a transmission shaft of the electric vehicle driven by the first and second motors; receiving a vehicle speed signal indicative of a vehicle speed of the electric vehicle and an accelerator signal with the vehicle control unit; calculating a torque demand of the electric vehicle based on the vehicle speed and the accelerator signal; deciding a power demand of the electric vehicle based on the torque demand; executing a first power distribution law to extract a distribution ratio from a distribution ratio database based on the vehicle speed, a current gear of a transmission connected to the second motor, and the power demand; adjusting a ratio of a power outputted from the first motor to a power outputted from the second motor according to the distribution ratio; calculating a driving resistance to the electric vehicle with the vehicle control unit by using a vehicle load estimation algorithm; selecting a shifting map out of a plurality of shifting maps according to the driving resistance; identifying a target gear of the transmission based on the selected shifting map, the vehicle speed, and the accelerator signal; and judging whether the target gear is equal to the current gear of the transmission with the vehicle control unit, with the vehicle control unit keeping executing the first power distribution law and maintaining the target gear of the transmission if the target gear is equal to the current gear, and with the vehicle control unit using a gear shifting driver to shift the current gear of the transmission to the target gear if the target gear is different from the current gear.