Modeling And Studying Of Control Method On Turbine-Generator Of The Industrial Waste Heat Power Generation System

Organic Rankine cycle low-temperature waste heat power generation can recycle waste gas of industrial emissions, solar, terrestrial heat, biomass and some low-grade thermal energy for power generation, at the same time the structure of the system is simple and easy to control. It can play a vital role in the recovery of waste heat and energy conservation. The paper mainly studies turbine and generator's modeling and control method, which is based on the industrial waste heat power generation system, and establishes a small low-temperature waste heat power generation experimental device. The maximum conversion efficiency of heat generators is 7.6%.First of all, the paper analyzes the parameters of organic refrigerant R600a in the organic rankine cycle waste heat power generation system. Organic fluid vapor's energy consumption is mainly from enthalpy variation in the scroll expander. The physical enthalpy is a measure of the saturated steam's pressure difference consumption in scroll expander. Therefore, the paper determines the scroll expander's control method which is the control of organic refrigerant pressure difference, and then control the scroll expander output power, dynamic torque.Secondly, the paper establishes the scroll expander's mathematical model and simulation model. According to the mathematical model to determine the pressure difference, the output torque by refrigerant vapor mass flow, and design the flow controller PID. The PID controller can adjust the mass flow's error signal and then the scroll expander can remove dynamic torque.What's more, the paper establishes the wound rotor generator (Double-fed generator) mathematical model to determine the control method for the stator flux oriented vector control. Accoring to wind turbine similar theory, the paper mainly enhances refrigerant vapor's mass flow and increases scroll expander's output torque. The scroll expander's output power is regarded as generator's given active power, according to simulation results to verify the correctness of control method and achieve independent regulation of the generator's active power and reactive power.Finally, the paper builds a small low-temperature waste heat generator experimental device and uses organic fluids R600a to experiment. The paper verifies the control stratrgy of scroll expander pressure difference that it is correctness. According to the experimental data, increasing the scroll expander pressure difference can reduce the irreversible loss of low-temperature waste heat system and improve the efficiency. The low temperature waste heat power generation system's maximum efficiency is 7.6% in the room temperature conditions.