| CT, X-ray and CV machine, which use high voltage generator system to control the X-ray tube. These generators work in continuous operation with intermittent loading mode, basing on switching power supply technology and resonant technology, the output voltage and current range from40to150kV and0.5to1250mA, respectively. In particular, good transient and steady-state performances of high voltage generator system can’t be achieved under wide load variations. Generator system includes three important sub-systems, DC power, filament power and anode power. In this paper, theory analyses and research about these sub-systems and their load X-ray tube is carried out, for the purpose to master the high voltage generator system design technical and improve the generator system’s performance.The resonant converters’nonlinear behavior creates difficulties to computing control laws and practical implementation. For this reason, a PFM high power high voltage generator system simulation software package is introduced, which is developed on MATLAB. System mathematical model is introduced, a practical resonant parameter design techniques for serial-parallel resonant topology converters is presented, and the controller is designed. Simulation and experimentation results verify that the method allows the components to be selected and stresses to be determined rapidly for design engineers. It is helpful for designing and validates the control law of converter. Applying appropriate changes, the simulation model are also suitable for other resonant converters.X-ray tube, which is one expensive, short life, consumable equipment, inside which, motor is used to drive the anode target rotation, to dissipate heat and avoid damage. The motor, which is sealed inside the tube, has no speed sensor, thus the speed of the anode target could not be detected directly. This paper provided a method which is based on the motor control theories, with the application of Radix-2FFT arithmetic according to DFT, covert the signal of stator current from time domain to frequent domain, using the spectrum estimate the anode target speed, eliminating the harm to X-ray tube which is caused by the abnormal target speed. Simulation results and test results testified that this method is up to the requirement. At present, the method has been use in the X-ray products. Tube filament is nonlinear. It was controlled via look up table method at large output power range. Under this control approach, the overshoot and steady-state error of the output tube current is larger, the filament control system’s immunity for interference is bad and the use life of X-ray tube will be reduced either. For these reasons, X-ray tube ARC suppressor is placed in order to limit arcing current and a neural network-PID control scheme is established in order to improve the filament control system’s precision. The algorithm of online self-adjusting is used to improve the control performance. The results of simulation show that the approach can improve the tube current output precision and can be available for a class of this nonlinear system.This paper presents series of novel technology for reducing acoustic motor noises inside the tube, which is being controlled by capacitor phase shift method. The experimental results show that the maximum level of tube acoustic is55.7dB when using the above improved methods at10800rpm. On the contrary, the level of tube acoustic reaches65dB if the conventional method is employed. This paper also investigates the special induction motors for X-ray tube drives which are driven by means of a three phase inverter. A control unit based upon DSP-320LF2407A is derived and implemented to control the special induction motor which is used in tube-CTR2150. Measurements proved that the performance of the application is effective.In order to enhance the reliability of DC voltage output of rectifier system and decrease the power switch’s broken down risk. In this paper, based on decrease voltage theory, discuss the method which used multi-circuit interlaced parallel BUCK circuit to fulfill DC-DC change, so as to decrease the DC bus voltage and voltage ripple, include performed theory analyses and system experiments is presented.According to the above theories, the high voltagegenerator system sample machines was built, system test with X-ray tube, control plant, table and the imaging system was carried out. These works not only included the determination of control parameters and analysis of practical test data for the generator system, but also included verifications for generator operating processes under variable load conditions. |
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