Open-circuit fault diagnosis method and system for staggered flyback type micro inverter

Abstract

The invention discloses an open-circuit fault diagnosis method and system for a staggered flyback type micro inverter. The method comprises the steps that an observer is built to carry out online estimation on the currents of a branch where any master switch device in the staggered flyback type micro inverter is located to generate estimation currents; a current residual is generated according to the estimation currents and actual currents obtained by actually measuring the same position; the norm H2 of the current residual is compared with a residual threshold value, and therefore whether an open-circuit fault happens to the master switch device in the staggered flyback type micro inverter or not is judged. The system comprises the observer, a current residual module and a comparison module, the observer is used for carrying out the online estimation on the branch currents to generate the estimation currents, the current residual module is used for generating the current residual according to the estimation currents and the actual currents, and the comparison module is used for comparing the norm H2 of the current residual and the residual threshold value and judging whether the open-circuit fault happens or not. According to the open-circuit fault diagnosis method and system, the open-circuit fault of the staggered flyback type micro inverter can be found in time, the fault can be processed in time conveniently, and the service life is prolonged.

Description

technical field [0001] The invention relates to the field of circuit fault detection, in particular to an open-circuit fault diagnosis method and system for an interleaved flyback micro-inverter. Background technique [0002] With the reduction of cost, reliability and efficiency of photovoltaic power generation, a new inverter structure - micro-inverter has emerged. Compared with the traditional centralized high-power grid-connected inverter, the micro-inverter can be directly connected to the AC grid by integrating a single photovoltaic module with varying numbers, and has the characteristics of maximum power tracking of a single module, low DC voltage, flexible expansion, and plug-in A series of advantages such as ready-to-use and high reliability. With the rapid development of the photovoltaic industry, the application of micro-inverters is becoming more and more popular, and the requirements for the reliability and safety of micro-inverters are also getting higher and ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide an open-circuit fault diagnosis method for an interleaved flyback micro-inverter, so as to solve the technical problem that cannot be detected in time when an open-circuit fault occurs in a certain main switching device of the interleaved flyback converter

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