Starting method for communication interconnection line-free multi-converter parallel system

Abstract

The embodiment of the invention provides a starting method for a communication interconnection line-free multi-converter parallel system. The method comprises the steps of obtaining a direct current side voltage of an inverter in a pre-charge process; obtaining a pseudo random number according to the direct current side voltage; obtaining an expectation value of an inverter unit as a pilot inverter unit, and carrying out +1 processing on the expectation value and a preset value to obtain a processed expectation value; carrying out residual value calculation on the +1 processed expectation value through utilization of the pseudo random number, thereby obtaining residual value; judging whether the expectation value and the residual value are consistent or not, determining that the inverter unit is the pilot inverter unit if the expectation value and the residual value are consistent, controlling the inverter to be started, and controlling an output side contactor to be closed; and if theexpectation value and the residual value are inconsistent, when a bus voltage sensor detects a bus voltage, following the bus voltage, thereby controlling the inverter to be started. The problem thatthe parallel system is started unsuccessfully due to the fact that the pilot inverter is fixed, once a fault occurs in the pilot inverter within a starting process, a follow-up inverter cannot detecta parallel bus voltage is avoided.

Description

technical field [0001] The embodiment of the present invention relates to the technical field of rail transit, and in particular to a method for starting a multi-machine parallel system of converters without communication interconnection lines. Background technique [0002] At present, based on the long-distance, strong interference and high reliability requirements, it is determined that the auxiliary parallel control of urban rail trains needs to adopt the droop strategy without interconnection wires. [0003] The premise of realizing the control of a multi-machine parallel system of converters without communication interconnection lines is the normal start-up of each auxiliary converter in the entire parallel system, especially the start-up sequence. In the prior art, the method of determining the pilot converter is to fix the pilot converter, that is, to fix a certain converter as the first-start converter. [0004] However, with the existing technology, once the leadin...

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Problems solved by technology

[0005] The embodiment of the present invention provides a start-up method for a multi-machine parallel system of converters without communication interconnection lines, so as to overcome the problem that in the prior art, once the lead converter fails during the start-up process, the subsequent converters cannot detect the parallel bus voltage, it will cause the parallel system to fail to start

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