Conventional vacuum control in a milking system is accomplished by using a vacuum pump, sized for the maximum air flows into the milking system, running at a full speed. The difference between the pump capacity and th...Conventional vacuum control in a milking system is accomplished by using a vacuum pump, sized for the maximum air flows into the milking system, running at a full speed. The difference between the pump capacity and the necessary flow of air is compensated by allowing air to enter the system through a regulator. The solution presented in this paper uses a VFD （variable frequency driver） in order to drive the vacuum pump at a controlled speed, so that the air removed equals the air entering the milking system. The VFD technology is able to adjust the rate of air removal from the milking system, by changing the speed of the vacuum pump motor. The VFD is controlled by a computer using a virtual instrument in order to emulate a PID （proportion integration differentiation） regulator. The tests aimed to evaluate the vacuum regulator characteristics and vacuum stability. A statistical analysis of the experimental results was performed and it showed that there was a significant difference between the experimental results obtained for the two methods of vacuum regulation （with vacuum regulator and VFD controller respectively）. The experimental results proved that the used of the VFD controller led to a higher vacuum stability in terms of the error between the set vacuum value and the achieved values.展开更多
The operational frequency range of RF system at HIRFL-CSRe (cooling storage experimental ring) is 0.5-2 MHz, and it works in fundamental and second harmonic. It includes five sections: ferrite ring loaded RF cavity, R...The operational frequency range of RF system at HIRFL-CSRe (cooling storage experimental ring) is 0.5-2 MHz, and it works in fundamental and second harmonic. It includes five sections: ferrite ring loaded RF cavity, RF generator, low-level system, computer system and cavity cooling. The cavity is based on the coaxial resonator type which is short at the terminal with one gap and loaded with domestic ferrite rings. The RF generator is designed in a push-pull mode. The low-level control system is based on PID, DSP, FPGA and DDS9854+USB interface and has three feedback loops. This RF system is designed independently and manufactured domestically. For the first time, it realized the pulse modulation, variable harmonic and CW operational modes. The maximum output power is up to 70 kW and the 10 kV RF voltage is used to capture the irradiative beam and decelerate the beam from 400 to 30 MeV/u.展开更多
文摘Conventional vacuum control in a milking system is accomplished by using a vacuum pump, sized for the maximum air flows into the milking system, running at a full speed. The difference between the pump capacity and the necessary flow of air is compensated by allowing air to enter the system through a regulator. The solution presented in this paper uses a VFD （variable frequency driver） in order to drive the vacuum pump at a controlled speed, so that the air removed equals the air entering the milking system. The VFD technology is able to adjust the rate of air removal from the milking system, by changing the speed of the vacuum pump motor. The VFD is controlled by a computer using a virtual instrument in order to emulate a PID （proportion integration differentiation） regulator. The tests aimed to evaluate the vacuum regulator characteristics and vacuum stability. A statistical analysis of the experimental results was performed and it showed that there was a significant difference between the experimental results obtained for the two methods of vacuum regulation （with vacuum regulator and VFD controller respectively）. The experimental results proved that the used of the VFD controller led to a higher vacuum stability in terms of the error between the set vacuum value and the achieved values.
文摘The operational frequency range of RF system at HIRFL-CSRe (cooling storage experimental ring) is 0.5-2 MHz, and it works in fundamental and second harmonic. It includes five sections: ferrite ring loaded RF cavity, RF generator, low-level system, computer system and cavity cooling. The cavity is based on the coaxial resonator type which is short at the terminal with one gap and loaded with domestic ferrite rings. The RF generator is designed in a push-pull mode. The low-level control system is based on PID, DSP, FPGA and DDS9854+USB interface and has three feedback loops. This RF system is designed independently and manufactured domestically. For the first time, it realized the pulse modulation, variable harmonic and CW operational modes. The maximum output power is up to 70 kW and the 10 kV RF voltage is used to capture the irradiative beam and decelerate the beam from 400 to 30 MeV/u.
