Stable Switching Rule Design And Fault Detection For Buck Converter Via Affine Switched Systems

As one of the core of modern power electronic system,DC-DC converter has important engineering applieation value.Their normal operation is of great signifieance to ensure the stable,efficient and high-quality operation of the whole system.With the development of high frequency and integration of electronic technology,high efficiency has become a research hotspot of power electronics.With the arrival of intelligent and digital era,DC-DC converter is widely used in industrial production,energy saving and errvironmental protection,national defense technology and other fields.Therefore,it is necessary and significant to speed up the stable and efficient control of DC-DC converter.At the same time,with the real-time change of running time,running state and other actual conditions,the original characteristics of the device also be changed,resulting in failure which lead to security risks and economic losses.Therefore,fault detection is particularly important and significant in both engineering application and theoretical research.This paper take DC-DC converter as the research object,DSP as the control module,and the circuit based on the modeling of affine switched system as the basis of stable control to explore the problem of fault detection.Its main structure is as follows:Firstly,Firstly,this paper adopts the BUCK converter as the controlled model to design the overall hardware scheme of the BUCK converter,including power drive circuit,step-down main circuit,sampling and feedback circuit and other specific hardware schemes.By comparing the devices with different parameters and according to the measured data,the stability of the system and the accuracy of the data are compared to select the appropriate devices,and the hardware platform of the converter is built.Then,in order to reduce the interference of control signals,the digital controller DSP28335 is used to output real-time variable pulse-width modulation signals for control,and the conversion between analog and digital quantities is also studied to realize the programming control of the software,which are derived from the high-performance analog-to-digital conversion and pulse-width modulation functions of DSP.Secondly,combining the stability control based on the modeling of the affine switched system with the hardware platform construction in the previous chapter,the stability control verification of BUCK converter based on the modeling of the affine switched system is realized,which is based on DSP and hardware circuit.The control rule collects the real-time inductive current and capacitor voltage continuously for real-time calculation,selects the maximum lyapunov function in the multiple sets of lyapunov functions in the affine switched system,forces the output pin in the DSP to set the high level,and completes the closed-loop control of the hardware circuit.In the third chapter,the theoretical derivation of stability control based on the modeling of affine switched system is discussed in detail.Taking BUCK converter as an example,the feasibility and effectiveness of stability control are verified by hardware platform experiments.Finally,the typhoon semi-physical platform is used to replace the hardware circuit to realize the stability control based on the modeling of the affine switched system.Then,based on this,the study of fault detection is carried out,and an observer suitable for BUCK type DC-DC converter is designed to complete fault detection of components,including inductance fault,capacitor fault and load fault.In the fourth chapter,the stability control is verified by the typhoon semi-physical platform.Then the fault model and the design of observer are discussed in detail,and the typhoon semi-physical platform is taken as an example to verify that the fault detection can be realized quickly and accurately when the components fail.