光伏光热一体机的双光电跟踪太阳控制器研制

Development of double photoelectric solar tracking controller for photovoltaic-thermal integration device

针对聚光型光伏光热一体机的太阳跟踪精度和跟踪范围相互制约问题,设计了粗跟踪和精跟踪双光电传感器,由粗跟踪光电传感器大范围捕捉太阳位置,精跟踪光电传感器精确地把聚光光斑锁定在整块光伏电池板上;分析聚光光斑跟踪精度,计算驱动推杆运行频率;采用单片机控制电路,优化跟踪控制策略,使得双光电传感器协调稳定工作。试验研究表明该双光电跟踪太阳控制器用于光伏光热一体机,可实现0°~180°捕捉太阳,且跟踪误差小于0.5°;光伏光热一体机可获得电能和热能的双重效益。

A concentrating Photovoltaic/Thermal(PV/T)integration device is normally confined to the mutual restriction of sun tracking accuracy and tracking range.In this study,a novel high-efficient solar tracking controller with dual-sensor joint control was designed to optimize the electrical and thermal performance of the PV/T system.The rough surface plane of glass was introduced to the PV/T integration device,where the sunlight was reflected to the concentrating cell components for multiple times concentrating,thereby increasing the power generation of solar cell per unit area.Part of concentrated light and heat was still collected,although the flowing water was cooling through the cells in the PV/T panel.A plurality of light-gathering units were fixed on the long axis of azimuth drive,while connected through the height angle linkage frame,for the tracking of sun azimuth via the azimuth push rod.A height angle push rod was used to push the parallelogram connecting rod for the height angle of the sun.The specific procedure was:1)A power conditioning circuit was used to amplify small piece signals of the solar cell,and then to convert into a standard signal for a photoelectric sensor.Two sensors were used on the east and west frame to capture the azimuth angle of the sun whereas another two sensors were on the north and south for the altitude angle of the sun.Four photoelectric sensors were installed at the top of the light-concentrating frame on the side of a rectangular parallelepiped to form a rough tracking photoelectric sensor,where the condensed light spot was collected from the reflection of the plane mirror.Another four sensors were installed at the four corners of light-concentrating cell assembly for a fine tracking photoelectric sensor.2)A single chip of Atmega 32 was selected as the core control circuit.The rough tracking photoelectric sensor was used to capture the position of the sun in a large range whereas the fine tracking photoelectric sensor was utilized to precisely locate the condensing spot on the entire photovoltaic panel.3)A coordinated and stable performance of dual photoelectric sensors was achieved after the optimization of the tracking control strategy.Specifically,two parameters were optimized,including the tracking accuracy of the spotlight,and the driving frequency of the push rod.The angle sensors were installed on the azimuth and altitude drive shafts,where the azimuth and altitude tracking of the sun were collected per minute.A comparison was made on the theoretical and astronomical data.Furthermore,a dual photoelectric tracking sun controller for PV/T integration device was also tested in Xiamen City of South China(118.09°E,24.56°N)on July 11,2018.An optimal combination was obtained,where the sunlight was captured from 0°-180°with a tracking error of less than 0.5°.The movement of the angle push rod was slow-fast-slow,and the running time interval of the height angle push rod was always maintained at 4-5 min/time.The PV/T integration device generated 3.94 kW·h on the same day,and the working temperature of concentrating cell module was between 53-60℃.Light and heat of 18.25 MJ(5.07 kW·h)were collected,1.29 times of photovoltaic effect.