Load-efficiency Analysis And Test Research Of Bulldozer Electrical Drive System

Improving the efficiency of bulldozer’s electric transmission system and realizing highefficiency transmission under intelligent control strategy are of great significance for bulldozers to save energy and reduce emissions and promote the development of bulldozers’ intelligence.The load-efficiency relationship of electric transmission system is an important basis for system design matching.This paper studies the efficiency of the electric transmission system and the law of the load-efficiency relationship under typical working conditions of bulldozers by developing and building an electric transmission test bed and simulating the loading of the typical working conditions of bulldozers on the developed test bed,thus laying a research foundation for the optimal design and system matching of the high-efficiency electric transmission system of bulldozers.Based on a comprehensive analysis of the load characteristics of bulldozers under cyclic conditions,this paper proposes four operating conditions,namely,soil cutting condition,transportation condition,unloading condition and no-load condition,as typical simulated loading conditions for bulldozers.Then,the structure of bulldozer series electric transmission system,parallel electric transmission system and hybrid electric transmission system is analyzed,and the key technologies of series electric transmission system engine-generator unit and its control technology,power distribution and energy management technology,drive motor and its control technology are studied.Using its key technology,an electric transmission test bed was developed and built,and a simulation loading test study under typical working conditions was carried out on the electric transmission test bed.The efficiency of the electric transmission system of bulldozer under various typical working conditions,the load-efficiency relationship under various typical working conditions and its variation law were emphatically discussed.The results show that the series electric transmission system is more suitable for bulldozer’s complicated cycle operation,and the developed electric transmission test bed can meet the requirements of bulldozer’s cycle operation simulation loading.The efficiency of the electric drive system is relatively high under the typical simulated loading conditions of the.and the efficiency of the bulldozer electric drive system has a positive correlation with the load.