Research on Constant Current-Constant Power Control for Capacitor Charging Power Supply in Adjustable Frequency Phase-Shift Modulation

As an auxiliary lithotripsy tool for treating kidney stones, the laser has gained extensive application in the biomedical field. Enhancing the charging speed of the internal capacitor charging power supply (CCPS) is the main development demand for clinical applications. The LCC resonant converter topology is widely employed in CCPS. To quicken the charging speed of CCPS, the charging strategy of constant current-constant power (CC-CP) control in adjustable frequency-phase shift modulation (AF-PSM) under continuous current mode (CCM) is proposed. Before reaching the rated power, CCPS is charged to adopt constant current control, and during the rated power period, it is charged to adopt constant power control. By utilizing the integral separation proportional integral controller, the issue of overshooting during the switching time between constant current and constant power charging is effectively resolved. By proposing adjustable frequency phase-shift modulation, the problem that it is difficult to maintain zero-voltage switching (ZVS) characteristics in the whole charging process by phase-shift modulation (PSM) is solved. The simulation results indicate a 32% reduction in charging time compared to the traditional constant current control while realizing the ZVS characteristic of the entire charging process.