Instantaneous Power Control Strategy Of Microturbine Power Generation System Based On Supercapacitor Energy Storage

As an important kind of distributed power system microturbine(MT) power generation system(MTGS) has high power density, high reliability, low emission and other characteristics. So MTGS has broad application prospects in the aerospace, defense and other industries such as ship industry, oil and gas exploitation. In order to meet some special requirement of application, MTGS performance is constantly improving and perfecting. To accommodate to impact load and improve system efficiency, this paper will thoroughly research instantaneous power control of MTGS based on super-capacitor energy storage technology, for seeking an effective way to solve the problem in principle and conducting experimental study to verify these methods.First of all, this paper proposes the novel MTGS structure based on super-capacitor energy storage suitable for impact load, which can fast balance system transient power flow to provide power required by impact load and absorb regenerative electric power. Instantaneous power flow of system energy conversion process is analyzed, and then the ideal control of various forms of energy conversion is achieved, takeing into account to enhance the conversion efficiency. Accurate MT power model is established，which can reflect efficiency and flow characteristics of compressor and turbine in MT under all operating conditions through the analytical method. Established models include power generation model, power conversion model and other power models. The system simulation analysis and controller design are carried out through above models.Secondly, against poor stability issue of classical control, the instantaneous power closed loop and state feedback control method is proposed. State feedback control parameters and state observer parameters change with system parameters，convergence characteristics under all operating conditions achieved through closed loop poles assignment. The results prove that this control method has the strong robust stability under all operating conditions. Using the efficiency law of MT affected by speed, the optimal efficiency variable speed control method of MT is put forward. The results show that the efficiency of the new method is significantly higher than the fixed speed operation. Instantaneous power control of permanent magnet synchronous generator (PMSG) achieves high internal power factor operation on the basis of the instantaneous power smooth control, reducing copper losses and improving system efficiency.For output power adjustment slow response problem of traditional MTGS, instantaneous power rapid control strategy is proposed based on the impact compensation. Control algorithm of instantaneous compensation power is raised by power response prediction of MT generator set and load identification. The high power dynamic response of super-capacitor energy storage can compensate low dynamic response problem of MT output power, so the instantaneous power of the system is real balance to ensure that the DC bus voltage is smooth and adaptability of MTSG is enhanced for impact load.Finally, for experimental study of instantaneous power control a physical simulation system is constructed by the method combining actual prototype system part and physical simulation equivalent system part. Instantaneous power fast compensation control with impact load and unload experiment results show that fast compensation strategy based on MT output power prediction and load identification ensures the real balance of power flow to achieve the system smoothly running for impact load. Ultimately it is proved that instantaneous power fast compensation control is a good solution to the problem of impact load.