Zhe Design Of Digital Decoupling Controller For Buck-Boost Converter With Constant Power Load

With the continuous development and utilization of new energy sources,new energy distributed DC power supply system has been widespread concern,where the conversion of energy is inseparable from the DC-DC converter.The generation of new energy sources are mainly solar energy,wind energy,water and so on,but this kind of new energy due to the impact of the environment,resulting in instability,discontinuity and a series of problems in the supply of electricity,So in the DC power supply system of new energy distribution,DC-DC converters must adapt to intermittent and randomness in the transformation of electrical energy.In this paper,taking Buck-Boost converter for example,The Buck-Boost transform is decomposed into three sub-modules:the disturbance module,the voltage loop module,the current loop module with the large signal decomposition modeling.with the inverse system method decoupling,eliminating the effect of input voltage disturbance and load disturbance on the output voltage,thereby eliminating the cross-coupling of the current loop and the voltage loop,so that the disturbance control,dynamic characteristic control of voltage loop,dynamic characteristic control of current loop of Buck-Boost converter becomes the independent process independent each other,to achieve decoupling control.The control method can be independently designed for current loop and voltage loop,thereby simplifying the controller design.The open-loop transfer function of voltage loop and current loop is the first-order integral system after the decoupling,the first order linear system can uses quadratic optimal regulator,the voltage loop adopts P-type regulator,and the current loop adopts PI type regulator.And then use MATLAB for simulation verification,Including:the performance of power perturbation and load disturbance of Buck-Boost converter,and the Performance of power Perturbations with Constant Power Load.Finally,a prototype of the decoupling control principle of Buck-Boost converter with constant power load is designed,Buck-Boost converter,the main converter using DSP2812 to achieve digital controller design.Constant power load converter is Buck converter,with the main converter constitutes a two-level cascade system.The experimental test included:the stability of the main converter under load disturbance.As well as the performance of load disturbance with constant power load.The results show good performance of the decoupling controller.