Research On The Control System Of Steam Temperature And Pressure For Dish Solar Thermal Power Generation

Under the grim background of energy shortage and environment pollution, it becomes human desperate need to exploit and utilize renewable energy such as solar energy. Dish solar thermal power generation is the most potential technology in solar thermal utilization, thus it has broad prospects for development. Thanks to the instability of solar radiation, steam temperature and pressure control system is the bottleneck of solar thermal power generation. This paper belongs to863Project-research on metal phase change thermal energy storage technology and energy storage boiler in solar thermal power generation, in order to solve the problem of steam temperature and pressure control in dish solar thermal power generation(1) This paper clarifies the basic working principle of dish solar thermal power generation, and then analysed key technologies involved in the system such as concentrator, receiver, tracking control, thermal energy storage materials and solar heat engine. gives energy analysis of concentrator and receiver, introduces the experimental platform of dish solar thermal power generation.(2) According to the dynamic characteristics of control object of drum water level, it designs Fuzzy PID self-turning controller, the simulation result shows that under the given water level value, flow of steam’s step disturbance and flow of feed water’s step disturbance, Fuzzy PID self-turning drum water level control system has good control quality, such as no oscillation basically, no overshoot, fast response and small steady state error. The control effect is better than cascade three impulse drum water level control system.(3) According to the dynamic characteristics of control object of super heated steam temperature, based on multi-capacity standard transfer function, it designs state feedback controller. The simulation result shows that under the flow of desuperheating water’s step disturbance, state feedback super heated steam temperature control system has good control quality, such as no oscillation basically, no overshoot, short dynamic transit time and small steady state error. The control effect is better than cascade super heated steam temperature control system.(4) According to dynamic characteristics of control object of steam pressure, combining the sunshine and temperature factors in Guangzhou region, take advantage of the characteristics of Al-Si alloy phase change material, calculating the main steam pressure transfer function and delay time. Based on the degraded and approximate model of main steam pressure and quadratic optimal control theory, it designs main steam pressure sub-optimal controller. The simulation result shows that under the heat source’s step disturbance, linear quadratic sub-optimal control of main steam pressure can guarantee short dynamic transit time and steady control process, but can not eliminate steady state error.(5) This paper introduces the operating principle of dish solar thermal power generation system, and then designs the automatic control technological process. Moreover, comparing and analyzing Siemens S7series PLC, at last, it have choosed Siemens S7-200PLC. To give the address distribution for input and output devices, after that, it designs peripheral hardware circuit, including power module, processor module and analog quantity extend module. And to develop simple steam temperature and pressure control program and make the electrical control cabinet.