Strömsensor

Strömsensor, or current sensor, is a device used to measure electrical current in a conductor and convert it to a signal proportional to that current for monitoring, control, or protection. Current sensors are used in power electronics, energy management, and industrial automation to track load, detect faults, and enable closed-loop control.

The main technologies are shunt-based sensors, Hall-effect sensors, current transformers, and Rogowski coils. Shunt sensors place a low-value precision resistor in series with the current path and measure the resulting voltage drop with an amplifier; they provide high accuracy and fast response but require a galvanic connection and produce burden voltage. Hall-effect sensors use the magnetic field generated by current; they can be open-loop or closed-loop, enabling DC measurement and galvanic isolation. Current transformers are suitable for AC measurements with high isolation but do not measure DC; Rogowski coils are flexible, AC-only sensors with wide bandwidth and are useful for large or awkward geometries.

Output and integration: Many sensors output a proportional voltage or current (for example 0-5 V, 0-10 V, or 4-20 mA) or digital signals through interfaces such as I2C, SPI, or PWM. They may include isolation barriers, protection features, and temperature compensation. Accuracy ranges from a few tenths of a percent to a few percent, depending on type, current range, and temperature.

Applications and considerations: Strömsensorer are used in motor drives, battery management systems, renewable energy inverters, smart meters, laboratory test benches, and automotive power systems. When selecting a sensor, consider the current range, whether DC or AC measurement is required, isolation, bandwidth, accuracy, environmental conditions, and cost.