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71M6543H 参数 Datasheet PDF下载

71M6543H图片预览
型号: 71M6543H
PDF下载: 下载PDF文件 查看货源
内容描述: 可选增益1或8的一个电流电能表计量芯片的补偿 [Selectable Gain of 1 or 8 for One Current Energy Meter ICs Metrology Compensation]
分类和应用:
文件页数/大小: 157 页 / 2164 K
品牌: MAXIM [ MAXIM INTEGRATED PRODUCTS ]
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71M6543F/H and 71M6543G/GH Data Sheet  
3
Functional Description  
3.1  
Theory of Operation  
The energy delivered by a power source into a load can be expressed as:  
t
E = V (t)I(t)dt  
0
Assuming phase angles are constant, the following formulae apply:  
.
.
P = Real Energy [Wh] = V * A * cos φ* t  
Q = Reactive Energy [VARh] = V * A * sin φ * t  
P2 + Q2  
.
S = Apparent Energy [VAh] =  
For a practical meter, not only voltage and current amplitudes, but also phase angles and harmonic  
content may change constantly. Thus, simple RMS measurements are inherently inaccurate. A modern  
solid-state electricity meter IC such as the Teridian 71M6543 functions by emulating the integral  
operation above, i.e. it processes current and voltage samples through an ADC at a constant frequency.  
As long as the ADC resolution is high enough and the sample frequency is beyond the harmonic range of  
interest, the current and voltage samples, multiplied with the time period of sampling yields an accurate  
quantity for the momentary energy. Summing-up the momentary energy quantities over time results in  
accumulated energy.  
500  
400  
300  
200  
100  
0
0
5
10  
15  
20  
-100  
-200  
-300  
-400  
-500  
Current [A]  
Voltage [V]  
Energy per Interval [Ws]  
Accumulated Energy [Ws]  
Figure 24: Voltage, Current, Momentary and Accumulated Energy  
Figure 24 shows the shapes of V(t), I(t), the momentary power and the accumulated power, resulting from  
50 samples of the voltage and current signals over a period of 20 ms. The application of 240 VAC and  
100 A results in an accumulation of 480 Ws (= 0.133 Wh) over the 20 ms period, as indicated by the  
accumulated power curve. The described sampling method works reliably, even in the presence of dynamic  
phase shift and harmonic distortion.  
3.2  
Battery Modes  
Shortly after system power (V3P3SYS) is applied, the 71M6543 is in mission mode (MSN mode). MSN  
mode means that the part is operating with system power and that the internal PLL is stable. This mode  
is the normal operating mode where the part is capable of measuring energy.  
v1.2  
© 2008–2011 Teridian Semiconductor Corporation  
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