Research On Active Protection And Control Of DC Microgrid

The short-circuit of the DC microgrid will cause serious losses such as the burning of the power supply and the damage of a large number of power electronic devices.Based on the controllability of power electronic devices,applying active protection control to short-circuit protection of DC microgrids is becoming a popular active protection strategy.This paper takes the DC microgrid with multi-energy energy storage system as the research object,and establishes an analysis model for analyzing the fault characteristics of the DC microgrid.It can fully reflect the fault dynamic characteristics of the converter under the fault condition of the DC microgrid.Conduct inter-electrode short-circuit fault analysis on a DC microgrid containing multi-energy energy storage systems,and find out the inter-electrode short-circuit faults in the three converter modes of bidirectional DC/DC,three-phase interleaved DC/DC and three-phase AC/DC similarities and differences.On this basis,a DC microgrid control and protection cooperative active protection method based on a fully controllable device insulated gate bipolar transistor IGBT to suppress inter-electrode short-circuit current and its start-up criterion is proposed.It can solve the problem of inter-electrode short-circuit faults in the DC microgrid,and realize active protection using the characteristics of the power electronic components in the converter.The main research work of this paper is as follows:(1)This paper takes DC microgrid with multi-energy storage system as the research object,and establishes the structure and mathematical model of DC microgrid with multi-energy storage system.This article analyzes the topology and working principle of the bidirectional DC/DC converter,and analyzes the design of the filter capacitor and inductance parameters of the bidirectional DC/DC converter.(2)This paper divides the DC microgrid with multi-energy energy storage system into several modules,and analyzes the short-circuit faults of each module respectively.This paper analyzes the fault characteristics of the inter-electrode short-circuit in the two-way DC/DC,three-phase interleaved DC/DC,and three-phase AC/DC of the DC microgrid,and finds out the similarities and differences of the inter-electrode shortcircuit faults in the three converter modes,and analyzes the characteristics of the interelectrode short-circuit faults in the three converter modes.Perform Matlab/Simulink simulation verification.(3)This paper studies the commonality of the faults and the key influencing factors of short-circuit current in the short circuit between the poles on the DC bus side under the three converter modes.On this basis,a DC microgrid control and protection cooperative active protection method based on a fully controllable device insulated gate bipolar transistor IGBT to suppress inter-electrode short-circuit current and its start-up criterion is proposed.It mainly solves the problem of inter-electrode short-circuit faults in DC microgrids,and realizes safe operation while simultaneously controlling fault currents.Finally,the effectiveness of the proposed fault blocking method is verified by Matlab/Simulink simulation to ensure the safe and stable operation of the system.