| 数据搜索系统,热门电子元器件搜索 |
|
ADE7761ARS-REF 数据表(PDF) 17 Page - Analog Devices |
|
|
|||||||||||||||||||||||||||||
ADE7761ARS-REF 数据表(HTML) 17 Page - Analog Devices |
|
17 / 28 page ![]() ADE7761 Rev. A | Page 17 of 28 Using Equations 1 and 2, the active power P can be expressed in terms of its fundamental active power (P1) and harmonic active power (PH): H 1 P P P + = where: 1 1 1 1 1 1 1 I V P β − α = Φ Φ × = ) cos( (3) and h h h h h h h H I V P β − α = Φ Φ × × = ∑ ∞ = ) cos( 2 (4) As can be seen from Equation 4, a harmonic active power component is generated for every harmonic, provided that harmonic is present in both the voltage and current waveforms. The power factor calculation has previously been shown to be accurate in the case of a pure sinusoid; the harmonic active power must, therefore, also correctly account for power factor, because it is made up of a series of pure sinusoids. Note that the input bandwidth of the analog inputs is 7 kHz with the internal oscillator frequency of 450 kHz. HPF and Offset Effects Equation 5 shows the effect of offsets on the active power calculation. Figure 22 shows the effect of offsets on the active power calculation in the frequency domain. ) cos( ) cos( 2 )) cos( ( )) cos( ( ) ( ) ( t I V t I V I V I V t I I t V V t I t V 0 1 1 0 1 1 1 0 1 0 1 0 ω × × + ω × × + × + × = ω × + × ω × + = × (5) As can be seen from Equation 5 and Figure 22, an offset on Channel 1 and Channel 2 contributes a dc component after multiplication. Because this dc component is extracted by the LPF and used to generate the active power information, the offsets contribute a constant error to the active power calcula- tion. This problem is easily avoided in the ADE7761 with the HPF in Channel 1. By removing the offset from at least one channel, no error component can be generated at dc by the multiplication. Error terms at cos(ωt) are removed by the LPF and the digital-to-frequency conversion (see the Digital-to- Frequency Conversion section). The HPF in Channel 1 has an associated phase response that is compensated for on-chip. Figure 23 and Figure 24 show the phase error between channels with the compensation network activated. The ADE7761 is phase compensated up to 1 kHz as shown, which ensures correct active harmonic power calculation even at low power factors. DC COMPONENT (INCLUDING ERROR TERM) IS EXTRACTED BY THE LPF FOR ACTIVE POWER CALCULATION 2v FREQUENCY (RAD/S) 0v V1 × I0 V0 × I1 V1 × I1 2 Figure 22. Effect of Channel Offsets on the Active Power Calculation FREQUENCY (Hz) 0 100 –0.05 –0.10 0 0.05 0.10 0.15 0.20 0.25 0.30 200 300 400 500 600 700 800 900 1000 Figure 23. Phase Error between Channels (0 Hz to 1 kHz) FREQUENCY (Hz) 40 –0.05 –0.10 0.05 0 0.10 0.15 0.20 0.25 0.30 45 50 55 60 65 70 Figure 24. Phase Error between Channels (40 Hz to 70 Hz) |
|
|
链接网址 |
| ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 数据表链接 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |