Taking the Measure of Photovoltaic System Output
Led by solar photovoltaics, the market for harvesting energy from renewable sources is booming. At the simplest level, a single residence is equipped with a PV system, generating electricity for its own use, and feeding the excess back to the national grid. At the highest level are utility-scale PV plants and solar farms, contributing to improved grid resiliency and helping governments meet global targets to reduce CO2 emissions.
Meanwhile, the smart grid concept is emerging as the way forward to provide a much-needed upgrade to national electrical infrastructures. The deployment of smart meters and off-peak tariffs will help utilities meet peak demands without excessively increasing overall capacity. Techniques such as ‘demand response’ and ‘transactive energy’ will help us exploit renewable energy generation effectively.
The keys to the success of the smart grid are visibility, controllability, and two-way communications. Underlying these critical aspects is the need for accurate monitoring of both energy production and consumption, and the gathering of data for analysis.
At the heart of measuring and monitoring, the performance of energy generation and consumption is the current sensor. This article will consider a select number of typical devices to show how they can be used in smart meters and energy-monitoring systems connected to photovoltaic panels.
Allegro offers a range of linear Hall-Effect sensors and integrated current sensors covering a number of applications, including the output side of the PV cell inverter, and for non-intrusive measurements and monitoring alongside smart meters.
Analog Devices, a pioneer in electronic energy metering, offers its CN0241 high-side current-sensing circuit with input overvoltage protection plus an evaluation package.
Finally, the 78M6613, 78M6618, and 78M6631 AC power-monitoring SoC devices from Maxim Integrated provide an alternative approach for single- and three-phase systems, also based on current-sensing technology.
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