Research On Energy-saving Speed Regulation Of Hydraulic Drive Unit Of Swash-plate Axial Piston Variable Pump With Constant Power Control And Three-Phase Asynchronous Motor

The hydraulic drive unit is the power source of molding equipment.The axial piston variable pump with constant power control is widely used in the field of forming equipment because of its good performance.Traditional hydroforming equipment is mature from the point of view of technology application.However,there is still much room for improvement in energy saving.In this paper,an energy-saving speed regulation strategy was studied for the hydraulic drive unit of swash-plate axial piston variable pump with constant power control driven by three-phase asynchronous motor.Firstly,the basic constitution of the hydraulic drive unit was outlined.Energy transfer and dissipation characteristics of this type of drive unit were analyzed from the perspective of energy flow.Then,the power loss of these two components in the working process is analyzed,and the semi-empirical formulas for the total power loss of the drive unit is derived by taking the three-phase asynchronous motor and swash-plate axial piston variable pump with constant power control as the object of study,combining its working principle.The drive unit test-bed was designed and built in order to verify the accuracy of the semi-empirical formulas and research the output characteristics of the drive unit.And the semi-empirical formulas were verified by experimental verification and error analysis.Moreover,a solution method of undetermined coefficients of the semiempirical formulas for the total power loss of the drive unit was proposed.In the end,the energy saving potential of hydraulic molding equipment driven by swash-plate axial piston variable pump with constant power control and three-phase asynchronous motor under ladder variable load conditions was analyzed.A corresponding energy-saving speed regulation strategy with the derived semi-empirical formulas was proposed.And an application case with the energy-saving speed regulation strategy was also analyzed.The result show that the energy-saving speed regulation strategy can save 42.4% energy in a single working cycle of RZU2000 T drive unit.