Control method for frequency conversion compressor unit for natural gas substation for automobile

Abstract

The invention discloses a control method for a compressed natural gas automobile compressed natural gas filling daughter station variable frequency compressor unit. The method comprises the following steps: the entire working condition range of a daughter station compressor is divided into different working condition sections; the optimum operation frequency of each working condition section is determined in advance; when the daughter station compressor works, real-time and periodical collection of gas suction pressure and exhaust pressure are carried out, then the optimum operation frequency in a corresponding working condition section is checked so as to adjust rotating speed of the compressor unit, and ensure the variable frequency compressor unit maintains higher motor operating efficiency within a load range of between 30 and 100 percent, and the motor operating frequency is 2 to 3 percent higher than that of non-reversible operation evenly, and is 7 to 8 percent higher than those of other frequency conversion modes; when gas suction pressure varies, relatively even gas charge can be achieved by adjusting the rotating speed; and the compressor unit can be quickly started without any independent soft starter.

Description

technical field [0001] The invention relates to a control method of a frequency conversion compressor unit, in particular to a control method of a frequency conversion compressor unit suitable for natural gas vehicle refueling sub-stations. Background technique [0002] As an alternative fuel for urban public transportation and short-distance transportation, compressed natural gas has been more and more widely used in China. In many places where there is no local gas source, it is necessary to develop a mother-child station model: set up a mother station at the opening of the natural gas pipeline, compress the pipeline natural gas to 20MPa and fill it into the gas storage cylinder group on the tanker, and then transfer it to city ​​sub-station. In the sub-station, it generally includes several groups of gas storage cylinders, a compressor and other facilities; when refueling the gas-consuming vehicle, first take gas from the gas cylinder of the tanker, and then use the gas ...

AI Technical Summary

Problems solved by technology

This scheme can meet the demand of gas volume to a certain extent, but the disadvantage is that the investment is increased and the overall utilization rate of the unit is not high; at the same time, whether the operating frequency of the variable frequency compressor unit is the best under different working conditions is not investigated.

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