Research And Design Of Controller For Off-grid Wind Power System

The controller is very important to the construction and well running of the off-grid wind power station.Generally, the former controllers almost worked in the stand-alone mode.They were able to control no more than one wind generator. In this mode,the installed capacity of wind power station is difficult to be changed and satisfy with the various wind environment.The two-stage control construction which concluded the main control board and the power modules was designed. Basing on the construction,the controller system was developed.Every power module control one wind generator to work.The main control board manage all of power modules and indirectly control the wind generators. Meanwhile, the main control board is charged with collecting the parameter of power station,operating the charge of lead-acid batteries,compensating the voltage change caused by temperature change, the input and output of alarm and communicating with PC.Through composing different number of low-power wind generators,the target of building wind power station of different capacity is realized. The content of this thesis concludes:1)Through researching the charge principle of lead-acid battery and analysising the charge curve of battery,the dividable charge program was improved and the step-by-step charge algorithm which is suitable to a good number of wind generators system was designed.2)Through researching the principle and analysising the features, functions and advantages of CAN fieldbus, the fieldbus is decided to be the inside bus of the controller system.3)The design of hardware was completed.The AT90CAN32 was choosed as the control chip.The circuits of singlechip minimum system,signal collection and conditioning,controlling input and output,CAN node commnication,temperature measurement with three-wire platinum resistor,serial port communication,MOSFET switch were designed and described in detail.4)The design of software was realized.Through enabling the on-chip resources and peripheral circuits, collecting and judging the parameters of charge or discharge,the main control board was able to directly control discharge circuit and indirectly control the wind generators through power modules.According to the algorithm of step-by-step charge,the flowchart of charge program was designed.The main board was embedded programmed.Finally,the main control board control the charge process according to the algorithm is realized.5)Finally,the hardware of the design was realized and software was debugged to run successfully. The prototype test proved the correctness of the design. It is convenient to increasing and reducing the system capacity. The reliality of the off-grid wind power station was improved.