With the help of storage battery, super capacitor and other energy storage elements, the diesel engine drives the generator to the energy storage element under the condition of small load, and then releases the stored energy to drive the motor under the condition of large load.
Advantages: not only the output torque of internal combustion engine can be balanced control, so that the working point of internal combustion engine is always located in the economic working area, but also the closed transmission scheme can be adopted for each hydraulic cylinder by using motor control technology.
Disadvantages: on the one hand, because the energy conversion manager has many links, such as diesel engine, battery, motor, hydraulic pump, hydraulic cylinder, hydraulic motor and so on, each link has energy loss, which leads to a large energy loss in the whole conversion process. Thus, the energy saving effect can be offset to some extent. On the other hand, because of the many links of energy conversion, the system tends to be complex and the technical requirements are improved accordingly. In addition, the oil-electric hybrid power technology has made the excavating power system change fundamentally from the structure, which has a great influence on the whole excavator manufacturing system, thus causing the increase of production cost.