Research On Estimation And Measurement Of Solar Array Characteristics

The field measurement of solar array can analyze and assess the power efficiency of solar energy station. However, the traditional method does not be used widely in characteristics test and assessment of solar energy station because of its inconvenience and bulkiness.This paper analyses, compares and researches the measurement of solar array deeply. The system takes advantage of a new measurement of solar array that samples the signal of voltage and current continually during charging capacitor by solar array to redraw the I-V characteristic of solar array. This method can test the I-V characteristic of solar array conveniently and quickly in contrast with the traditional method.Moreover, in order to represent the influence of temperature and irradiation to the characteristic of solar array, a physical mathematical model of solar array is established which based on short-circuit current(Isc), open circuit voltage(Voc), the voltage of MPP(Vm), the current of MPP(Im). The characteristic of solar array in varied temperature and irradiation can be established with the appropriated parameters deduced by the above model.Through the experiment of sampling array's voltage and current, it is found that rational disturbs do exist in this system and have fatal influence to the precision of sample. To obtain the exact characteristic curve, a digital filter is needed to deal with the data of AD conversion. So a digital filter of average value is introduced in system. And the experiment results are satisfied.A solar array tester for practice has been developed successfully. It can measure the solar array with the range of voltage and current from 0 to 600V and 5 to 100A respectively. The tester with DSP core could get excellent results by judging and adopting the different value of voltage and current, programmed amplifying and changing the frequency of sample. What more, it can establish the I-V characteristic of solar array according to the temperature and irradiation set by users. Therefore, the system can reflect the I-V characteristic of solar array completely.