The power system of parallel hybrid hydraulic excavator consists of engine, generator (motor), super capacitor, hydraulic system and so on. The mechanical energy of the engine is directly output to the hydraulic pump, the hydraulic pump drive arm hydraulic cylinder, the bucket rod hydraulic cylinder, the bucket hydraulic cylinder, the rotary motor and the walking motor.
In this power system structure, the average power required for the output load of the engine, the excess or insufficient part, is absorbed or supplemented by the engine (motor), so that the engine can work at a fixed working point or working area, improving the fuel economy and improving the emission of the engine. Supercapacitors are used to replace traditional batteries in the selection of energy storage devices. Compared with the traditional batteries, the super capacitor has the characteristics of fast charge and discharge speed, high charge and discharge current and high power.