Through-hole board mount hall-effect current sensor (or say magnetic current sensor) has been widely used in solar inverter system for a dozen years. This process is convenient for wiring and installation, no need to cut off the cable. However, open-loop through-hole hall-effect current sensor usually can't achieve high accuracy over both lifetime and temperature. Meanwhile, this is easy to fail during the installation and transportation processes due to the brittle magnetic core damage, which reduces the system reliability. On the contrary, in-package hall-effect current sensor can provide high accuracy combined with low drift, enabling accurate current measurements over both lifetime and temperature. Additionally, the in-package design also provides a compact design without sacrificing isolation performance, while reducing system complexity and cost. So, in recent years, there has a trend in solar inverter system to use in-package hall-effect current sensor to replace the traditional thorough-hole one, that benefits solar system performance, power efficiency and reliability.
This application note summarizes common solar application scenarios where in-package hall-effect current sensors, such as TI’s portfolios TMCS112x and TMCS113x, can be used. This document helps engineers to understand the basic requirements of current sensing in solar end equipment and how current sensors are used accordingly.
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Current measurement accuracy and reliability is critical to solar inverter system, because this determines the control accuracy of the power stage and further affects the energy harvest efficiency. For high-voltage solar inverter systems, through-hole board mount hall-effect current sensor (or for example, magnetic current sensor) have intrinsic isolation nature and the measurement does not intervene the measured circuit that provides wiring and installation convenience.
Close-loop hall-effect current sensor can provide high accuracy, fast response, low sensitivity and low non-linearity error, the sensor needs extra magnetic core, coil and high-power amplifier to drive the coil that makes close-loop hall-effect current sensor has more complex structure, large size, higher power consumption and higher cost than those of open-loop hall-effect current sensor. So, considering the tradeoff between performance and complexity, open-loop through-hole board mount hall-effect current sensor have been widely used in solar inverter system for a long time.
However, open-loop through-hole hall-effect current sensor usually cannot achieve high accuracy over both lifetime and temperature. Meanwhile, this is easy to fail during the installation and transportation processes due to the brittle magnetic core damage, which reduces the system reliability. This can be great if open-loop hall-effect current sensor can provide sufficient performance of accuracy, response, sensitivity, and non-linearity as close-loop one. The better option is using in-package hall-effect current sensor such as TMCS112x and TMCS113x. TI’s in-package hall-effect current sensor can provide high accuracy combined with low drift, enabling accurate current measurements over both lifetime and temperature. Additionally, the in-package design also provides a compact design without sacrificing isolation performance, without adding system complexity or cost. In recent years, there has been a trend in solar inverter system to use in-package hall-effect current sensor to replace the traditional thorough-hole one, that benefits solar system performance, power efficiency, and reliability.