带恒功率负载的Buck-Boost变换器的稳定性研究
Study on the Stability of Buck-Boost Converter with Constant Power Load
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摘要: 本文利用无源性研究带恒功率负载的Buck-Boost变换器稳定性问题。恒功率负载的负阻抗特性使Buck-Boost变换器输入阻抗实部负定,使变换器为非无源的,可导致其不稳定。对此,本文设计了一种基于端口受控的耗散哈密顿模型的无源控制器,使Buck-Boost变换器输入阻抗实部由负定变为正定,保证了变换器无源性和稳定性,进而可实现变换器具有好的稳态和动态性能。仿真结果表明,无源控制器可保证带恒功率负载的Buck-Boost变换器无源性和稳定性,并使变换器具有优秀的稳态和动态性能。Abstract: In this paper, the stability of buck-boost converter with constant power load (CPL) is studied by passivity. Owing to the character of negative of CPL, the real part of input impedance of the Buck-Boost convertor is negative definite and non-passive, which can make the convertor unstable. In order to make the real part of the input impedance of the Buck-Boost converter changes from negative definite to positive one, a passivity based controller based on port controlled Hamiltonian with dissipation (PCHD) is designed to ensures the passivity and stability of the convertor, and then convertor has the good steady-state and dynamic performance. Simulation result shows that the passivity based controller can ensure the passivity and stability of the Buck-Boost with CPL, and the convertor has the good steady-state and dynamic performance.