DC-DC Converter Fault Diagnosis Method Using Adaptive Sliding Mode Observer

With the advancement of science and technology,the application of DC-DC converter systems has expanded to more fields,including aircraft,spacecraft,power system power generation,and traction and shipboard power networks.Especially the renewable energy that has received widespread attention in recent years,solar photovoltaic arrays are one of the most important renewable energy sources for power generation,and DC-DC converters,as an important part of solar photovoltaic power generation,can ensure the efficient conversion performance of the system and maintain the normal operation of the system.Because photovoltaic power generation is widely used in battery charging equipment,street lamps,and other aspects,if the system fails,it may not only cause the system to fail to operate normally but also may be fatal.Therefore,it is necessary to find a suitable control strategy and fault diagnosis method,To improve the reliability,efficiency,and safety of the system.First,according to the two working states of the DC-DC converter,the working principles of the two DC-DC converter topologies studied are briefly introduced.and use the state-space averaging method to establish the mathematical models of two DC-DC converters under normal conditions.In addition,the main research questions of this article are constructed.Secondly,taking Boost converter converter as example,the fault diagnosis problem of DC-DC converter components under open-loop system is studied.According to the designed adaptive sliding mode observer,an appropriate sliding mode signal and adaptive law are derived.The Lyapunov function is used to analyze the boundedness of the state estimation error and the parameter estimation error to ensure the accuracy of the adaptive law in the online estimation of component parameters.The simulation model of the DC-DC converter was established by using offline digital simulation software,and the method was simulated and verified.In the simulation,the inductor and capacitor failures under different noise conditions are considered,and the hardware-in-the-loop simulation platform is used to verify the failure of the boost converter components.To solve the closed-loop control of the DC-DC converter and solve the sensor fault problem,the sensor fault diagnosis problem of the Single-ended primary inductor converter circuit under the closed-loop system is studied.The minimum Lyapunov function control strategy is adopted to realize the closed-loop control of the DC-DC converter.Based on the closed-loop control of the SEPIC circuit,the main circuit parameters and an adaptive sliding mode observer are designed.Observe the inductor current and output voltage through an adaptive sliding mode observer,and the observed and measured values will produce residual errors.The residual is compared with the designed threshold to realize the sensor fault diagnosis of the DC-DC converter.The thesis builds the main circuit model through PLECS simulation software and simulates and verifies the control strategy and sensor fault diagnosis method.The simulation results show that the control strategy designed in this paper can control the stable operation of the circuit.The fault diagnosis method proposed in this paper can not only detect the faults of different types of components and realize the fault estimation of the components but also detect the occurrence of multiple sensor faults at the same time,which verifies the effectiveness of the method.