Fault diagnosis method of single-phase parallel inverter

Abstract

The invention discloses a fault diagnosis method for a single-phase parallel inverter, and the method comprises the following steps: S1, building a hybrid logic dynamic MLD model of a hybrid system according to the topological structure of the single-phase parallel inverter, the state of a switching tube trigger signal, and the flow direction of an input current; s2, establishing a Luenberger observer according to the MLD model to obtain a state space expression of the system; s3, obtaining the observed value of the output current of each inverter unit of the system through a Luenberger observer, thereby obtaining the observed value of the circulating current of the system; s4, comparing the actual value of the system circulation with the observed value to obtain a residual signal; s5, analyzing residual signals when different switch tubes have open-circuit faults; and S6, setting a threshold value to eliminate the influence of other factors in an actual system on a fault diagnosis result so as to position a faulty switch tube. The method does not depend on a specific single-phase parallel inverter control method and has universality.

Description

technical field [0001] The invention belongs to the field of fault diagnosis of power electronic converters, in particular to a fault diagnosis method of a single-phase parallel inverter. Background technique [0002] Inverters play a vital role in such power systems. In high-capacity power systems, inverters are usually operated in parallel. The parallel inverter system can easily increase the total power of the system; when the power of the system is constant, by increasing the number of parallel inverters, the power and voltage and current stress shared by each inverter module can be effectively reduced . The parallel operation of inverters is the key way to realize the large capacity and power regulation of the system. [0003] However, as the number of inverter modules in a parallel system increases, as well as complex and variable operating conditions and the aging of the components themselves, the probability of failure also increases. The faults of power semicond...

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Problems solved by technology

[0005] In order to solve the problem that the open-circuit fault of the switching tube of the single-phase parallel inverter cannot be located, the present invention proposes a fault diagnosis method for the single-phase parallel inverter. The specific scheme is as follows:

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