Energy has a particularly important strategic position in the national economy. In the context of China's society focusing on energy conservation and emission reduction, LED lamps are widely used in daily lighting for their energy-saving features. However, there is currently no national performance standard for evaluating the key parameters such as power and luminous flux, which leads to a mixed market, which causes great trouble for consumers when purchasing energy-saving products. Various local groups are also drafting LED lighting product standards. However, there are no systematic LED lighting performance requirements at home and abroad. The key technical parameters of LED lighting products, such as power, luminous flux and lighting efficiency, are also varied. This paper mainly analyzes the current quality of LED lamp downlights, such as power, luminous flux and lamp performance, through the measurement data of 276 LED downlights . At the same time, it compares the international and domestic popular evaluation methods. Find reasonable judgment principles and provide strong technical support for the development of performance standards. First, the current quality analysis of LED downlights At present, manufacturers generally mark power and luminous flux in the marking of the luminaire, and the luminaire performance index has not been marked in the mark. This article focuses on power, luminous flux and luminaire performance indicators to clarify the quality of LED luminaire products on the market. In this paper, 46 batches of 276 LED downlights were selected as the analysis samples, and the power covered 3.3W to 35W; the diameter ranged from 3cm to 19cm. The technical parameters of the power, luminous flux, and luminaire performance of the 276 downlights were measured. Power Power is an important parameter to evaluate the energy consumption of the product. The actual power consumption of the lamp will deviate from the rated power. The deviation describes the consistency between the measured power and the nominal power. The consistency is used as an evaluation index to evaluate the product quality. . We estimate the deviation between the measured power and the rated power by calculating the percentage of the measured power and the rated power, as shown in Equation 1: Ηp=measured power/nominal power*100% In order to visually understand the distribution of the entire sample, 276 luminaire data is visually represented by a scatter plot, as shown in Figure 1. Figure 1 Measured percentage of measured power and nominal power consistency percentage As can be seen from Figure 1, most of the data is distributed in the interval of 90% to 120%. Qualification analysis is performed according to the actual power and rated power percentage limits, as shown in Table 1. Table 1 Qualification table of measured power and nominal power consistency at different limits It can be seen from Table 1 that the measured power of 58.7% of the lamps is greater than the rated power claimed by the manufacturer in the mark, indicating that there are still low power standards and misleading consumers on the market. 2. Luminous flux Luminous flux is an important indicator for evaluating the performance of LED downlights. The higher the rated luminous flux, the higher the luminous flux can be obtained at the same power. In order to sell products better, some manufacturers will raise the rated luminous flux and mislead consumers. We evaluate the deviation of the actually measured luminous flux from the nominal luminous flux by calculating the percentage of the actual measured luminous flux versus the nominal luminous flux, as shown in Equation 2: Ηl=measured luminous flux/rated luminous flux*100% (2) In order to visually understand the distribution of the entire sample, Figure 2 gives a scatter plot of the measured luminous flux and the rated luminous flux. Figure 2 Scatter plot of the ratio of measured luminous flux to nominal luminous flux It can be seen from Fig. 2 that the data occupies a range from 40% to 140%, which is relatively scattered, indicating that the actual measured luminous flux has a large deviation from the rated luminous flux. Further, the eligibility analysis is carried out according to the measured percentage of the luminous flux and the rated luminous flux, as shown in Table 2. Table 2: Qualification rate of initial luminous flux at different limits As can be seen in more detail in Table 2, the measured initial luminous flux is less than the nominal nominal luminous flux given by the manufacturer in the mark, accounting for 57.97%, indicating that the actual measured luminous flux of the LED downlight is mostly smaller than the nominal. The rated luminous flux, the current LED downlight on the market has a high standard rated luminous flux phenomenon, which will cause misleading to consumers, causing market confusion. 3. Lighting performance The first two paragraphs of the article introduce the current status of LED downlight power and luminous flux. There are phenomena of low power and high luminous flux. Such a nominal is to obtain higher luminaire performance. So, what is the performance of the actual LED downlight? We calculate the actual luminaire performance by dividing the measured luminous flux by the measured power, as shown in Equation 3: η=measured luminous flux/measured power (lm/w) (3) In order to be more visual and intuitive, Figure 4 shows the scatter plot of the measured luminaire performance of the 276 downlights selected this time. Figure 4 scatter plot of the measured luminaire performance As can be seen from Fig. 4, most of the actual measured luminaire performance data are concentrated in the interval of 30 to 80, and there are few tens of more than 80. The luminaire performance is an energy-saving evaluation parameter. The luminaire performance limit is specified in the energy efficiency standard of the lighting product. Table 3 shows the percentage of qualified products under different luminaire performance limits. Table 3 The pass rate of the measured luminaire performance at different limits According to the requirements of the luminaire performance greater than 60, the pass rate is only 55.43%. Nearly half of the LED downlight luminaires do not meet the requirements. The luminaire performance is less than 75, which is only 5.07%, and the luminaires with less than 50 luminaires. The total number is 30.8%. If the requirements of 80% of the products are qualified, the limit value of the luminaire performance can only be set at 40 lm/W, which is obviously inconsistent with the energy-saving and high-efficiency characteristics of the LED lighting products. The actual measurement performance of the LED downlights is not available to the manufacturer. As high as the publicity, the current LED downlights are still mixed, and the manufacturing technology needs to be improved. Of course, in daily lighting, parameters such as color and color rendering are parameters that users should pay attention to. We cannot ignore the comfort of lighting because of blind pursuit of high lamp performance. Second, the comparison of evaluation methods The characteristics of LED downlights are significantly different from those of lamps using conventional light sources. Traditional light sources, such as fluorescent lamps, gas discharge lamps and other light sources, are basically products with mature production technology and relatively complete product specifications. The indicators of the light source have also been standardized. Therefore, for lamps using traditional light sources, power measurement And evaluation is also relatively easy, in the product standard of the luminaire, the type test can only measure one luminaire. LED is an emerging light source in the lighting industry. It is still in the stage of technology development. The characteristic stability of LED light source and various technical indicators have not yet formed mature technology. There is no standardized product, including the power, specification and light intensity of LED light source. The uncertainty of parameters such as lamp performance, input current and voltage brings measurement instability to lamps using LED light sources. Therefore, the traditional method of evaluating a lamp sample is obviously not suitable for the measurement requirements of LED downlights. Many local standards and technical specifications have been formulated in China, and two of them have a wide range of technical specifications. First, the semiconductor lighting products jointly issued by the National Development and Reform Commission, the Ministry of Housing and Urban-Rural Development and the Ministry of Transport in August 2010. Technical Requirements (2010 Edition) (hereinafter referred to as technical requirements). The other is the technical specification for LED downlight energy-saving certification issued by CQC in December 2010 (hereinafter referred to as CQC technical specification). At present, various standardization organizations in the world are studying the evaluation methods of LED luminaire performance. The IEC/PAS 62722-2-1 (ED1.0) LED luminaire performance standards drafted by the IEC/TC 34D Standards Committee describes the use of statistical evaluation methods in the IEC/TC 34D Standards Committee LUMAX Maintenance Working Group 2011 At the technical meeting held in June, many experts proposed to use the average instead of the concept of statistics. Table 4 lists the above evaluation methods. Table 4 List of different evaluation methods As can be seen from the above table, there are still some major differences in the existing evaluation methods. First, the two domestic technical specifications are compared. The evaluation method of the initial luminous flux and initial luminaire performance of the CQC technical specification is the same as the technical requirements of the NDRC, but the power evaluation methods are quite different. Internationally, the IEC draft requires that not only individual samples meet the requirements, but also the average of the samples must meet the relevant requirements of the standard. Of course, the evaluation method for the average value of the sample is still under discussion. At present, the IEC organization has two evaluation methods for the average value, one is that the unilateral limit value under a certain confidence probability does not exceed the specified value, and the other is the average value. Not exceeding the specified value. Moreover, the IEC draft specifies a one-sided upper limit for power, and specifies the unilateral lower limit for initial luminous flux and luminaire performance. Of course, there is a more obvious difference. The limit specified in the IEC draft is the manufacturer's claimed value, while the two domestic technical specifications specify the specific value, which is also related to the nature of the specification, CQC technical specifications and The NDRC's specifications are based on energy-saving products, and the IEC standard draft is based on performance criteria evaluation. The purpose of the two is different, so the evaluation indicators are different. Below, we analyze the sample data in four specific ways according to the above three categories of evaluation methods, as shown in Table 5. Below, we further analyze the data in Table 5. First, we analyze the limit determination of each parameter. It can be seen from Table 5 that the NDRC's requirements for power are relatively loose, and the samples that meet the power requirements of the NDRC account for 93.48% of the total. The CQC and IEC drafts impose an upper limit on the power limit, ie the measured value does not exceed 10% of the rated value. According to the CQC limit requirement, if the single lamp is used according to the traditional method, the pass rate is 83.70%. If the requirements of 6 samples per group are met, the pass rate will drop to 80.43, which is more stringent than the traditional single sample evaluation method. For power, the average manufacturer will have a low power rating to indicate that its product consumes less power, but the actual power consumed often exceeds the nominal power. The CQC and IEC drafts stipulate the upper limit of the measured power, so that the difference between the actual measured power and the nominal value should not be too large, so as to curb the illegal behavior of the manufacturer in the market to confuse the market, it is more scientific and reasonable. For luminous flux, the NDRC and CQC use a bilateral limit method, and the IEC draft uses a unilateral lower limit method. Ordinary manufacturers will want their products to have low power, but high luminous flux and higher energy-saving characteristics. Therefore, the nominal luminous flux will often be elevated, but the actual luminous flux may not be able to illuminate the nominal luminous flux. Therefore, it is necessary to limit the lower limit value of the measured luminous flux. Therefore, the unilateral lower limit method of the IEC draft is more scientific. For the performance of the luminaire, whether it is the NDRC or the CQC technical specification, the lower limit of the luminaire performance is specified without exception. This is also closely related to the two specifications being energy-saving specifications. The energy-saving specification needs to stipulate the luminaire performance limit. Screen out energy-saving products with high performance. The IEC draft is a performance standard for LED luminaires, which is used in a wider range of applications and therefore only specifies requirements that are based on the manufacturer's stated value. Since most products do not claim luminaire performance at present, this article assumes the luminaire performance value according to the IEC draft method, but the LED downlight that claims to be high luminaire performance is actually not as good as the manufacturer advertises, and the luminaire performance is higher than The sample of 60 only accounted for 56.52%, even if the pass rate according to CQC was only 52.17%. This data shows that the technology of LED lighting products needs to be improved. Below, we will further analyze the average evaluation method in the IEC draft. At present, there are two evaluation schemes for the average value, one is the method of using the confidence probability unilateral value, and the other is the method of the average value limit. Taking the initial luminous flux as an example, see Table 6. Table 6 List of pass rates of luminous flux in accordance with the requirements of the IEC draft The number of sample groups satisfying the condition 1) is 29 groups, and the one-side lower confidence limit that satisfies the condition 2), that is, the average luminous flux is 31 groups, indicating that the condition 2) is lower than the condition 1 requirement, and only the condition 1) can be satisfied. Claim. If we increase the limit requirements for the average, such as the requirements of 3) and 4), the number of qualified groups has dropped, and even 4) is more severe than 1). When we set standards, we should fully consider the rationality and operability of the limit requirements, and verify the limits by certain data. The IEC organization is still discussing the method, and we will also feed back the results to the IEC organization and actively participate in the discussion of the IEC draft. The method for evaluating the average value limit is similar to the method for the confidence probability unilateral value limit, and the average value is evaluated. As can be seen from the data in Table 4, if the average limit is the same as the limit of a single sample, there is no sense of existence. Therefore, this paper gives the qualification rate under different average limits, and provides data and basis for the standard limit selection. Comparing the methods in the IEC draft, it can be seen from Table 4 that if the limit and the average limit of the individual samples of each group are the same, then a single sample can meet the requirements, whether it is the confidence probability unilateral value limit of the average or There is no need for an average limit. If the individual sample limits differ from the mean limits, then the pass rates at different limits need to be compared to select the most reasonable limits. Third, the conclusion This paper first analyzes the performance parameters of LED downlight power, luminous flux and luminaire performance, and gives the qualified rate of LED downlights according to different indicators, and evaluates the quality of LED downlight products on the market. Secondly, it introduces several existing eligibility evaluation criteria, and analyzes the qualification levels of power, luminous flux and luminaire performance according to these different evaluation methods, and compares the differences between different evaluation methods to provide a standard selection evaluation method. Technical Support. Light reflectors in China with resonable price and good quality,We hope to establish cooperative relationship with you. Light Reflector,Aluminum Light Reflector,Street Light Reflector,Energy Save Light Reflector Yangzhou Huadong Can Illuminations Mould Manufactory Co., Ltd. , https://www.light-reflectors.com