Figure 3: Power-monitor ICs such as the Texas Instruments LMP92064 use a pair of 12-bit ADCs to support power calculations for applications with less-demanding accuracy requirements. (Courtesy of Texas Instruments)
For even simpler monitoring requirements, designers can often use a single ADC with an external multiplexer to monitor voltage and current on each line. In fact, 8:1 multiplexers such as the Intersil DG408, Maxim Integrated MAX4581, and ON Semiconductor MC74HC4051A can support three-phase applications that require more basic power monitoring.
Designers can find ADCs with integrated multiplexers designed to support a broad range of channels, data throughput, and conversion resolution. For three-phase power monitoring, devices such as Analog Devices AD7699, Linear Technology LTC2372, and Texas Instruments ADS8688 integrate an eight-channel multiplexer with ADC and dedicated analog front end for each channel. For example, each input channel of the TI ADS8688 includes over-voltage protection, a programmable gain amplifier (PGA), low-pass filter, and driver feeding the shared multiplexer to the single ADC.
Conclusion
Ensuring grid power quality requires highly accurate measurement of voltage and current on each phase. For grid-tied energy-harvesting systems and equipment, power monitoring similarly requires high-resolution, simultaneous sampling of line voltage and current using ADCs providing a dedicated converter for each channel. Although basic fault monitoring builds on the same principles as high-accuracy measurement applications, designers can use lower-resolution ADCs or multiplexed devices that offer high-resolution multichannel measurement at lower throughput rates. Designers can find ready availability of ADCs designed to meet this broad range of requirements for channel support, bit resolution, and sample rate.
自动翻译仅供参考
多通道采样精确的按键电力线监控
准确的电力线监控已在电网本身，而且在其边缘成为一个关键的要求，不仅集中。对于并网能量收集发电系统，甚至为终端设备，持续的电能质量特性分析，有助于确保电网和连接系统的健康状况。在功率监视系统的心脏，模拟 - 数字转换器（ADC）起到测量线路电压和电流的精度适合于每个应用程序的电平的关键作用。工程师可以从制造商包括Analog Devices公司，产科宝电子，Intersil公司，凌力尔特满足各种需求 - 从公用事业级系统精度所需收入的目的基本电源监视器用于检测线路故障，采用高性能ADC和相关组件， Maxim的集成，Microchip的科技，安森美半导体，电子脉冲和德州仪器。
