|
|
引用第0楼yrj109于2007-08-01 19:41发表的 关于CEC test 困惑 :# X5 ]) S- o* G3 o6 O
在做测试时会碰到下面问题:6 b C- T3 u! r1 D# Z5 @# h
1、有些产品在做测试时,输入功率会跳动(可以确定是产品造成的),此时输入功率这么取?本人是取最大值的,是否正确?
1 R+ E# [; G0 u ~ j2、做最后一项空载输入功率时(控标准顺序),有些产品在热态下会很大(如0.66W),但当产品完成冷下来后(大概一小时)输入轴功率又会变小(如0.35W). 取0.35W 是否正确?- o7 h7 B( P" y. S. d! @% T/ k
3、THD 值按标准计算公式得出会是在100%--300% 之间,标准里所提到的 THD值 是如何定的? 1 ]* F! C1 _8 ~8 Z% F( E2 P4 I
5 r# n9 `# Y- d; D
以下引用於:Test Method for Calculating the Energy Efficiency of Single-Voltage External Ac-Dc and Ac-Ac Power Supplies. v j8 S( [. \2 m8 P; v
& [, @& m8 s2 I8 i
d. Testing Sequence 4 ?2 Q3 `! u% {' r' ^
1 ]6 o# Z! C4 J7 w4 t- k0 nAs noted in IEC 62301, instantaneous measurements are appropriate when power readings are stable in a particular load condition. The UUT shall be operated at 100% of nameplate current output for at least 30 minutes immediately prior to conducting efficiency measurements. 6 E. v* o- Y5 X" Y! q4 u
) Q9 G1 j% B+ t' ~, G: ?2 }# y% SAfter this warm-up period, the technician shall monitor ac input power for a period of 5 minutes to assess the stability of the UUT. If the power level does not drift by more than 5% from the maximum value observed, the UUT can be considered stable and the measurements can be recorded at the end of the 5 minute period. Subsequent load conditions (see below) can then be measured under the same 5 minute stability guidelines. ) C4 @1 E Q- i {$ \& D* M" G: s
5 S, q; q2 z. E& yNote that only one warm-up period of 30 minutes is required for each UUT at the beginning of the test procedure.
0 g2 n* a8 b: B8 ?9 V, l+ ~( O- P* X( \$ g/ Z
If ac input power is not stable over a 5 minute period, the technician shall follow the guidelines established by IEC 62301 for measuring average power or accumulated energy over time for both ac input and dc output.
# i1 p7 ?7 m5 k$ y; y+ T! X+ a& l* C, E j% N
1、 你的做法是錯誤的,請參考上面的紅色字體部分。, t0 Y/ q x6 ^1 p
如果在測試時,输入功率会跳动,此時應按IEC 62301,取得5分鐘內的平均功率。2 W* X% c! [6 N/ @
3 o# _1 w/ e$ y6 h B3 s2、 我個人傾向於取0.35W,因為0.66W是一個假像。2 N% D; j& ?4 e9 F" ?" J' }7 s5 ~
. H4 u( d; j9 l& E) c4 x; F3、THD的計算方法請參考圖片的公式。說實話,我對THD也是不太明白。 引用Mikesu兄的說明給你參考一下:“THD 一般可用測 EN 61000-3-2 (電源諧波量測設備) 進行檢測. 或是高階的電力分析儀”。另外,CEC並未限制THD的數值,只需在報告列出數據即可。$ S9 x4 k0 l0 K. h4 ?. a
7 v3 X2 b, B m, F3 o |
本帖子中包含更多资源
您需要 登录 才可以下载或查看,没有账号?注册安规
x
|