Research on the Characteristic of the Electro-hydraulic Power Source Composed of Variable Speed Asynchronous Motor and Proportional Constant Pressure Pump

doi:10.3901/JME.2017.18.183

Abstract

Abstract: Electro-hydraulic power source is the power unit of hydraulic system, and its energy efficiency decided the whole hydraulic system efficiency. Currently, the variable displacement electric-hydraulic proportional integrated pressure control flow control power source, whose motor still run at rated speed during the non-working period produce lots of extra energy consumption, and the constant displacement pump power source driven by variable speed asynchronous motor hard to control the output pressure directly. Addressing those shortcomings, it is introduced that a method to construct new type electric-hydraulic proportional integrated pressure control flow control power source through using variable speed asynchronous motor driven proportional constant pressure pump. In this new type power source, no throttling loss pressure continuous control can be realized by changing the swinging angle of inclined plate and the output flow continuous control can be reached by changing the revolution speed of pump. Furthermore, for the problem of slow dynamic response in asynchronous electric variant speed driving, a solution is introduced that aided accelerating the launch and braking of the pump through adding hydraulic accumulator in main circle and bringing its high-pressure oil into the hydraulic pump inlet. Based on these theory, the electro-hydraulic power source test system is build, and its control characteristics of power, pressure, flow, compound of flow and pressure are studied. The results show that with the load pressure changes the flow control error of the test system does not exceed 0.5%, aided accelerating the launch and braking through adding hydraulic accumulator can make launch time and braking time of the variable-frequency motor from 1 s and 1.2 s down to 0.2 s and 0.5 s, and through reduced the motor rotation speed, the test system can reduce the energy consumption beyond 20% than use constant speed motor drive in several working situations such as pressure maintaining, pressure unloading, and constant pressure situation.

Key words: electro-hydraulic power source, energy saving, pressure and flow compound control, speed variable control

CLC Number:

TP212

YAN Zheng, QUAN Long, ZHANG Xiaogang. Research on the Characteristic of the Electro-hydraulic Power Source Composed of Variable Speed Asynchronous Motor and Proportional Constant Pressure Pump[J]. Journal of Mechanical Engineering, 2017, 53(18): 183-190.

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