SHROPSHIRE, UK -- Corac Group is developing new downhole gas compressor technology. The object of Corac's new compressor technology is to boost gas output from brownfield sites by as much 30-50% from otherwise un-economic wells.
During development and proving trials of the compressor, Corac carries out above-ground testing in their gas well 'flow loop' simulator. This calls for an effectively controlled power supply to the compressor.
A raw 3Ø supply is fed to a REO AC power supply unit which converts it to a variable 3Ø AC supply. This is then fed to a rectifier which converts the AC to DC (0-2500V). The variable DC voltage connects to an inverter that drives a motor in the compressor which, in turn, rotates an impeller at high speed to develop a pressure ratio across the compressor.
In this power system, the REO power supply is commanded by a control computer via its RS232 serial communication interface. Corac engineers can send control data that governs the speed of the motor driving the compressor via the RS232 port.