多動力馬達電動車電量平衡力矩分配策略

Abstract

本研究提出一套兼具電量平衡及力矩分配的電動車節能行駛策略，此電動車之動力架構採用15-kW直流無刷馬達搭配傳動齒輪箱，作為前輪之間接驅動動力源；後輪則由兩顆7-kW永磁同步馬達置於輪內，作為後輪之直接驅動動力源，並配有三電池組提供能量來源。控制策略中以車身穩定系統保持行車安全，並以粒子群最佳化法操作各馬達輸出力矩於高效率區間，作為行駛時節能力矩分配；而在多動力系統架構下，為解決各電池組電量不平衡之問題，策略結合固定比例力矩分配，車輛行駛過程中可基於滿足駕駛者之行車要求下，判斷電量狀況適時改變力矩分配模式而將電量差距控制在設定範圍內達到電量平衡之效果。 本研究除了以模型迴路模擬驗證策略性能外、並將策略建置於dSPACE MicroAutoBox中，整合感測器與電池管理系統所提供之策略所需狀態變數，並以底盤動力計以及實車上路實驗驗證策略可行性。實驗結果顯示，本研究之電量平衡力矩分配策略確實能在行駛過程中將電池組間電量差距維持在一定範圍內，並在直行與轉向模擬中提升旅程續航力約26.59%和7.67%；於實車實驗中，相較於分別以前後動力為主固定比例提升續航力約23.2%和10.82%，達到兼具電量平衡以及節能行駛之效果。

This research proposes an energy-saving driving strategy for electric vehicle (EV) both charge balancing and torque distribution. The power train of EV consists of three motors: a 15-kW front traction motor with gearbox and two 7-kW in-wheel motors installed inside both rear wheels and EV is equipped with three battery packs to provide energy source. The strategy will adjust torque command of motors by particle swarm optimization that motors can be operated in high efficiency region to save energy. To solve the problem of charge unbalancing, the strategy which combines fixed ratio torque distribution can keep the driving safety by electronic stability program and switch mode of torque distribution according to the charge state. Finally, besides of proving the performance of the strategy by model-in-the-loop (MIL) simulation, the charge balancing strategy is implemented in controller to verify the feasibility of real vehicle on the dynamometer and road. Experimental results show that the strategy can maintain charge gap within the set range, improve the endurance of 26.59% and 7.67% in straight and steering simulation and 23.2% and 10.82% compared with the fixed ratio torque distribution in the real vehicle experiment. The strategy achieves the effect of charge balancing and energy-saving driving.