Beschreibung:
Aiming at the increasingly used energy storage system (ESS) of the transformer area power grid, this paper has researched on the modelling and fault diagnosis of the ESS. A switching system model of the ESS is established firstly. According to the second method of the Lyapunov function, the system switching law is determined. And the expected switching sequences of the system are constructed based on the analysis of the working process of the ESS. Then the actual operating subsystem and switching sequences are identified by the fault characteristics and identification vectors of the ESS. A method by comparing the actual subsystem with the expected subsystem or actual switching sequence with expected switching sequence is proposed to carry out the fault diagnosis for power electronic circuits. The effectiveness and feasibility of the proposed method are verified by simulation and experimental results under the working conditions of open circuit and short circuit for the devices, respectively. The results show that the reliable operation can be guaranteed for the transformer on area power grid. The proposed method deeply integrates the idea of switching system, and it is easy to implement, fast to diagnose, and strong to be used versatility. It is hoped to provide a new idea for fault diagnosis of power electronic circuits