Induction generator voltage improvement using a new control strategy for turbo-expander driving systems

摘要

Turbo-expanders are relatively new sources of dispersed generation which are used to drive the electrical generators. The conventional pressure regulating valves are replaced by these devices in the gas pressure reduction station. Connecting the dispersed generation to the distribution networks especially for squirrel cage induction generators, may result in some power quality problems. These problems can be obviated using special devices in electrical networks or modifying the control system of the prime mover system in mechanical parts. In this paper, it is focused on the Point of Common Coupling (PCC) voltage where a turbo-expander driven induction generator is connected. A new control strategy based on fuzzy controlled PID is considered for the mechanical part of the turbo-expander nozzle system. The results show a better control of turbo-expander output power in a linear form over the full range of operating points. The other purpose of the control system modification is to improve the power quality and stabilize the PCC voltage in different operating point conditions.