光照强度对光伏抽水灌溉系统性能的影响

Influence of illumination intensity on performance of photovoltaic pumping irrigation system

为掌握光照变化对无蓄电池光伏灌溉系统运行特性的影响,搭建光伏灌溉系统开式试验台,试验测量了不同光照强度下的系统性能.试验结果表明:较低光照强度下喷头工作压力、射程随光照强度增大而增大,较高光照强度下随光照强度上下波动,射程变化趋势与工作压力变化趋势一致,但旋转周期变化趋势与工作压力呈相反规律;喷头工作压力变化趋势与光伏水泵出口压力、光伏组件输出功率变化趋势一致;光照强度1000 W/m^(2)附近系统运行参数达到阈值,喷头射程与工作压力最大值分别为9.8 m和0.44 MPa,水泵流量与出口压力最大值分别为1.68 m^(3)/h和0.45 MPa;未达到阈值前,影响水泵与喷头运行的主要因素是光照强度,运行参数变化幅度较大,达到阈值后影响因素主要为光照强度和温度,运行参数变化幅度较小;较低光照强度下,组合平均喷灌强度随着光照强度增大而增大;较高光照强度下,组合平均喷灌强度随着光照强度上下变化,与光伏组件输出功率的变化趋势一致;随着光照强度增大,喷头喷灌均匀系数和分布均匀系数逐渐趋近最高值,喷灌均匀系数最高达到88%.

In order to study the effect of the illumination intensity change on no photovoltaic battery working characteristic of the irrigation system,a battery-less photovoltaic irrigation system test was set up,including rotary sprinklers,photovoltaic pumps,inverters,photovoltaic panels and other components.The various operating data of the system at different illumination intensities were obtained.The results show that the fluctuation of sprinkler operating pressure,sprinkler range and sprinkler rotation period are affected by the illumination intensity variation at higher illumination intensity,but at lower illumination intensity,the range and pressure of the sprinkler increase with the light intensity increa-sing.Besides,the variation trend of the range is consistent with that of working pressure,but the variation trend of the rotation period is contrary to that of working pressure.The sprinkler pressure is coordinated with the pump outlet pressure and photovoltaic panel output power.The system operation parameters reach the threshold value when the illumination intensity is around 1000 W/m^(2).The sprinkler maximum range and working pressure are 9.8 m and 0.44 MPa.The pump maximum flow rate and outlet pressure are 1.68 m^(3)/h and 0.45 MPa.Before the threshold reaches,the pump and sprinkler have a larger operation parameters range,which are mainly affected by illumination intensity.When the light intensity is larger than the threshold the influence factors are dominated by the illumination intensity and temperature.The operation parameters change smaller at this time.The illumination intensity is a gain factor and the temperature is a depreciation factor.At lower illumination intensity,the combined average sprinkler irrigation intensity increases with the illumination intensity increasing.At higher light intensity,the combined average sprinkler irrigation intensity fluctuates with the light intensity,which is consistent with the variation trend of photovoltaic module output power.As the illumination intensity increases,the uniformity coefficients of sprinkler irrigation and distribution monotonically approach to the highest value,and the highest value of the uniformity coefficient of sprinkler irrigation reaches 0.88.