New Control Strategy of Series-Parallel Resonant X-Ray Machine

X-ray tube´s cathode space charge effect is the main interference for real-time control of x-ray tube current. Those factors making filament current drift are unpredictable, which affects the dynamic response performance of the tube current. In order to quickly respond to a wide range of X-ray tube anode voltage, based on closed-loop control strategy of X-ray tube current, real-time voltage control signal (duty cycle) is introduced into feed forward control part to constitute non-linear real-time dynamic compensator for X-ray tube´s cathode space charge effect, Filament current is introduced as a deputy control variable into the cascade control of tube current to rapidly respond the current lag, improve the accuracy and reduce the process time constant, Intelligent Chips are utilized to manufacture a high-performance low-cost controller for X-ray machine. MC34067 is utilized to construct main circuit of high-frequency quasi-resonant, which aims to achieve rapid soft-switch control for X-ray tube anode voltage, TL494 is utilized to construct main circuit of X-ray tube current control strategy, MCU is utilized to chose the compensation factor depending on anode voltage range. Based on above ideas, two sets of prototype are made to test, preliminary results show that these control methods and circuit devices are effective.