Research On Fault Diagnosis Of Three Phase Current Source Inverter

Current source inverter(CSI)has a wide range of application prospect in fields such as uninterruptible power supplies,power transmission and speed regulation,and grid-connected renewable energy sources due to their simple topology,great output waveform quality,and reliable short circuit protection.In many applications,the reliability requirements of power electronics equipment are relatively high.According to the survey,the switch is the most prone to failure in the entire system.Therefore,to improve the reliability of the system,it is necessary to detect and locate the fault switches.The first is to diagnose the fault when the switch fails,so that the system can be stopped quickly to prevent secondary damage to other components of the electrical system;the second is to identify the location of fault in time for easy maintenance;The third is to provide precondition for its fault-tolerant operation.With the wide application of current source converters,the research on fault diagnosis is also of great significance.First,the basic idea of model predictive control is introduced in this article.And then,Starting from the working state of the CSI,the switch sequence corresponding to the nine current vectors is clarified.Furthermore,the state space model of CSI is analyzed,and the prediction model of output current control is derived.The value function is set to make the output current follow given currents,and the influence of the sampling frequency on the current waveform is explored.Then,a method that can be used for fault diagnosis of current source inverter is introduced in this article.The method is based on output currents.In this paper,the principle of fault diagnosis method based on output current is analyzed in detail,and a method that can detect single switch fault and double switch faults of current source inverter is proposed.Simulation result shows that the method is simple and effective,and can accurately detect single switch and double switch faults.It can also be used in both model predictive control and traditional PR control.Finally,the main circuit of three-phase current resource converter system was built,and the FPGA control circuit based on the TMS320F28335 DSP and XilinxXC6SLX9-2TQG144 C FPGA was designed.Finally,the diagnostic method based on the output current was experimentally verified.The experimental results verify the correctness and feasibility of the theoretical scheme.