Research on the energy regeneration systems for hybrid hydraulic excavators

This paper deals with the method of how to regenerate the potential energy for a hybrid hydraulic excavator (HHE). After studying the structure and working cycle of the HHE, two energy regeneration systems are considered. Then, the control strategy and parameter matching for the proposed energy regeneration system (ERS) are discussed. United simulations with AMEsim and MATLAB/simulink for the conventional control system and two ERSs are carried out in this paper. An estimated 41% of the total potential energy could be regenerated at the lowering of the boom in accumulator-motor-generator system while the recovery efficiency in the motor-generator system is only about 17%, and it is also shown that the accumulator-motor-generator energy regeneration system (AMGERS) features better speed control of the boom and response characteristics than the motor-generator energy regeneration system (MGERS), hence, the AMGERS is a good configuration for the HHE at present.

Research highlights
► An new energy recovery system that combines the advantages of an electric and hydraulic accumulator is proposed.
► The control strategy and the parameter matching for the MERS and the AERS are studied.
► It is possible to increase the efficiency of the generator and downsize the generator with the hydraulic accumulator in the AMGERS.
► The AMGERS features better speed control and response characteristics than the MGERS.