Design Of The Digital DDVC High Pressure Generation Unit And Experimental Research

5GPa HTHP rheometer is one of the advanced laboratory instruments in the field of deep earth processes study. High pressure generation and control are the key technology, so its performance directly affects experiment results. In recent years, with the development of hydraulic and automation technology, supper high pressure is applied widely to space, geology, material, etc. The integrated and automated high pressure generator is much in demand especially. On the basic of detailed research on high pressure generator made by famous research scholar and company at home and abroad, a flexible and easy control and measurement system is developed to design a digital DDVC high pressure generation unit in this paper. Direct drive volume control and DSP digital control technology is used to make the generator has the performance of high accuracy, stability, integration and multiple interfaces.The whole system scheme is made through analyzing and researching the DDVC control system structure and performance. The machinery and hydraulic system are designed, processed, assembled and debugged to produce high pressure by two-way hydraulic cylinder. For further study on the output high pressure performance, a mathematical model of digital DDVC high pressure generation unit is established and simulated in Matlab/Simulink. The high pressure simulated results indicates that the output pressure performance is connected with shuttle time of directional valve, accumulator volume and work pressure. The pressure fluctuating quantity and dynamic performance are improved by using an accumulator and shortening the shuttle time.In order to make the system have good performance and meet the control and measurement requirement, the control system scheme based on TMS320F2812is designed, which includes AC motor space voltage vector control module, phase current, phase voltage, velocity, torque and pressure measurement module, data storage based on USB module, touch screen human-computer interaction module using MCU as controller, etc. The hardware of the control system comprises control circuit and power driving circuit. The DSP MSYS circuit, signal measurement circuit, alarm and protection circuit, SCI-bus and CAN-bus communication circuit, and interaction circuit are developed and integrated to achieve control system hardware design. The bridge rectifier circuit and IPM inversion circuit are made to amplify control signal to derive the AC servo motor. Some anti-interference measures including reasonable wiring, circuit isolation and filter are applied, to decrease the PCB and circuit electromagnetic interference and ensure the system stability and accuracy.The control system software including main program, data acquisition and treatment program, motor control program, pressure PID control program and human-computer interaction program is developed by object-oriented and structure modularization programming method. Multi-channel analog signal acquisition is researched and realized based on DSP to meet the demands of high accuracy measurement. Three-closed loop discrimination PID control strategy containing high pressure PID control loop, AC servo motor velocity PID control loop and motor stator current PID control loop, is applied to optimize the static and dynamic motor characteristics and improve the control accuracy. AC servo motor control is important as the system control object. Its performance directly affects the system stability and accuracy. The motor SVPWM control method is focused and realized.It takes overall debugging and testing on the designed digital DDVC high pressure generation unit. The SVPWM test control waveforms, phase current test waveforms and velocity test results show that motor space vector control algorithm on PMSM is carried out successfully and make the system have good performance. The PID control parameter adapted to the system is searched through PID parameter orthogonal test. The accumulator is applied to improve the output pressure characteristic. The pressure performance study shows that the shuttle time of directional valve and working pressure have a direct effect on the pressure output characteristics. The test research results lay the foundations of further study on ultra high pressure technology.