|
引用第0楼yrj109于2007-08-01 19:41发表的 关于CEC test 困惑 :
+ b9 r7 q; V/ e1 R, d在做测试时会碰到下面问题:2 \5 i; S& p4 C3 ]- t- V9 R3 v
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?
4 z; y% W; C, _# {" F4 M2、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?, z8 X( \" z+ B m1 s1 `' ~( L
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? ; t0 c$ H% a& U" c) W* m- B
- o! O ]! w2 D% w& l. ^ l0 K以下引用於:Test Method for Calculating the Energy Efficiency of Single-Voltage External Ac-Dc and Ac-Ac Power Supplies! C0 B; A$ h$ |
0 t4 P& A r- Q4 Y
d. Testing Sequence 9 r; T% Y6 M x$ Z5 o
! \: t- x5 f4 M6 N
As 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.
4 e( B: h! W- F" t* Y+ W# ^- n8 n; F Q6 ^
After 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. 1 W4 Y3 I& w0 A$ Y3 m- F
! E& ?* K- ^2 h* N
Note that only one warm-up period of 30 minutes is required for each UUT at the beginning of the test procedure.
; h2 K1 B% \2 Z6 X N* J8 Z t1 o7 f* c" q! u
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." z+ l$ q! D0 M
$ O) i4 [ _+ r. S1 N
1、 你的做法是錯誤的,請參考上面的紅色字體部分。0 @( [/ V+ H+ l' j: @: S1 `0 o
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。
) ^ m# w3 z" b3 }* a" |! a8 V0 W9 j2 t# `6 U
2、 我個人傾向於取0.35W,因為0.66W是一個假像。( a& n7 d% R1 | Q( J" r# T
5 M: d( L) F& u" O; \- M6 P' _" _; A3、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。* c9 U( T$ [9 C: d- U2 G6 I4 g
! x; x3 Z; X$ _2 l8 `
|
本帖子中包含更多资源
您需要 登录 才可以下载或查看,没有帐号?注册安规
x
|