Study on energy regeneration mechanism of switching inertance hydraulic system by using modal analysis

The energy efficiency of the conventional flow control of hydraulic systems using the pressure loss of throttle valves, which are widely used in construction machinery, is very low. If the switching inertance hydraulic system which is a kind of PWM control hydraulic system is used, a significant improvement in energy regeneration efficiency can be expected. The aim of this study is to develop a new analysis method which can consider the elasticity of oil and the influence of mass of the hydraulic cylinder and the structure in a typical hydraulic system which is more complex than the electrical PWM control system, and can help to understand the mechanism of energy regeneration and the effect of parameters on energy regeneration efficiency. A flow response analysis method is developed using the modal analysis method with approximate theoretical equations which can help to understand the effect of parameters. Next, a new definition of energy regeneration efficiency is proposed. Some calculations are carried out using the proposed response analysis method and definition of efficiency, and the mechanism of the energy regeneration in a typical hydraulic system is clarified and the effects of parameters on energy regeneration efficiency are noted.