Output Voltage Ripple Suppression of PPSS-LCC Converter for Medical X-Ray Application Based on Repetitive Control

The primary-parallel-secondary-series LCC resonant high voltage (HV) power supply with single-phase ac input has been widely applied for medical X-ray application. It requires extremely low ripple (<0.5%)>LCC converter at the same time. The dc-bus capacitance can, therefore, be remarkably reduced. This strategy has the advantages of no additional hardware costs, directly implemented in digital controller, and insensitive to accuracy of system parameters. Experiments are carried out on a practical 120 kV/900 W HV power supply and confirm the effectiveness of the proposed strategy. The peak–peak output voltage ripple is suppressed to only 0.36%, while the DC capacitance is significantly reduced to 1/12. Comparison of X-ray does prove that the image quality of X-ray machine is consequently greatly improved.