Research On Capacitor Charging Power Supply Based On Two-Switch Buck-Boost Converter

Capacitor charging power supply (CCPS) is an important component of pulsed powersystem. The capacitor charging power supply (the CCPS, Capacitor Charging PowerSupply) usually takes constant current mode, it has a large peak power, long charging timeinterval and a small long time average power. When multiple CCPSs are workingconcurrently, its peak power require a higher input power grade，when output power havereached their respective peak value, charging are finished, the output power plummet tozero, which has fairly great influence upon power grid.Aimed at the above-mentioned problems and features of the CCPS, a program isproposed that embedded an energy storage system in the CCPS, which can reducethe grade requirements and the impact of CCPS on the power grid. By analyzing andcomparing the storage program, combined with the basic characteristics of the CCPS, thepower energy storage system’s Energy storage devices use an Ultracapacitor, its converterselects Two-Switch Buck-Boost Converter.In this paper, the operating principle of the Two-Switch Buck-Boost is firstintroduced, and the State-space averaging model of Two-Switch Buck-Boost converter isestablished to deduce the inner current loop and power outer loop transfer function. Inorder to achieve a constant current charging and limited power charging, the currentclosed-loop parameters and the power of the outer ring closed-loop parameters aredesigned, and the rationality of the closed-loop parameters are verified with the help ofMATLAB simulation.Discussing the designs of the Two-Switch Buck-Boost Charging power supplymodules, from circuits which is related to the system-level (such as Power tube, Filterinductor)design to the control circuit (such as sampling circuit, the control panel),meanwhile, the power loss of the Charging power supply were analyzed. This paper havebuilt the Energy storage system experimental platform on the basis of the design andanalysis, and verified the feasibility of constant current charging. The experimental resultsshow that the circuit parameters and controller parameters are reasonable.