The Energy Recycling Electro-hydraulic Valve Controlled System Based On Direct Torque Control Method

With the continuous development of hydraulic technology and modern control theory, electro-hydraulic valve controlled system is widely used in military, industrial, and other fields for its high power density and large load stiffness. However, there are also some disadvantages such as the low energy efficiency and high quantity of heat. In this context, achieving an electro-hydraulic valve controlled system with high energy utilization rate and control precision become a hot research topic, and gets the very vital significance.The paper puts forward an electro-hydraulic control system with energy recycling, and designs the energy recycle device in the hydraulic circuit. The system adjusts the torque of the hydraulic motor to change the back pressure of hydraulic system, so that the trajectory of the hydraulic actuator can be controlled.The paper designs the hydraulic circuits of the hydraulic valve controlled system and electrical system for energy-recycling, establishes the mathematical model and analyzes the feasibility and controllability of the system. For the system, the control of the motor torque rapid and accurate so as to adjust the back pressure of the hydraulic system is the key that makes actuator movement meet the requirements.Based on this, this paper mainly studies the direct torque control algorithm to control the torque of asynchronous motor and analyzes the shortcomings of traditional direct torque control. An improved direct torque control method is proposed and a control scheme is designed based on the processor speed and maximum switching frequency of the inverter.For the improved direct torque algorithm, this paper designs the related hardware circuit and builds the experiment platform, in which the IPM module is used as inverter, and the ARM kernel microcontroller is used as controller.