| In recent years, Direct current high voltage power supply is widely used in various domains, such as electrostatic dust collection in manufacture industry, prospect equipment in mining industry, laser in optical industry and CT in medical science. Due to the effect of high voltage power in the application process of X-ray tube, people need to constantly adjust X-ray tube and filament voltage, in order to make X-ray tube working regularly. But it is inconvenient for people to adjust them repeatedly. Also due to the high voltage power will output extremely high voltage, it becomes a serious threat to personal safety of working staff. Therefore, people need to develop a new automation system to make it safety. A complete set of high voltage power supply contains not only a control system, but also the whole main technical parameters of high voltage power. Ripple is an important parameter of high voltage power supply, and a key criterion to evaluate the quality of high voltage power supply. However, the power will inevitably form ripple voltage due to the special structure of the direct current high voltage power supply. Ripple can cause serious damage to equipment, especially for some precise instrument, thus accurate measurement method for the direct current high voltage power is very important.This content of essay could be divided into two parts: First, we designed a set of power control system, in order to control the voltage and electric current of X-ray tube at the same time. Second, we designed a device to measure the ripple. Based on the analysis of the working principle of X-ray tube, we designed a set of automatic closed control system according to the characteristics of its operation. This system could adjust the high voltage power supply and filament power supply at same time, meanwhile the X-ray tube creates X-ray steadily. The core hardware part of control system is a single chip micro-compute, and the auxiliary circuit includes Power supply circuit, Isolating circuit, Filter circuit, D/A conversion circuit and Voltage circuit. In addition, the software of control system could adjust the functions of high voltage power supply and filament power supply simultaneously; also adjust the functions of over voltage protection and over current protection as well. The incremental PID algorithm was used in the main core algorithm of the system, and the control system will adjust the power supply stability and quickly. The final experiment results showed that the designed control system has faster control speed, higher stability and better security.In terms of ripple measurement, this essay showed the research about the production of Dc high voltage power supply ripple and the representation method of ripple. We designed a ripple measurement experiment device and introduced the selection method of experiment devices. At last, we got ripple of spectrum and waveform. Meanwhile the ripple coefficient and pulsating coefficient were collected by calculating. Through analysis of the experiment result, we found the theory support to reduce the amplitude of the ripple. In this research, the measurement technique is very easy, the speed of measure is swift and the result of measure is accurate. |
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