High voltage (≥400V) fully electric systems aim to lower the current consumption for the traction system that moves the vehicle. This requires isolating the solution so that the ‘hot’, high-voltage side can provide current measurement to the ‘cold’ side (attached to low-voltage ≤5V microcontrollers or other circuitry).
The high current presents an issue when trying to measure with a shunt resistor due to the I2R power dissipation.
To use a shunt in these conditions means that you must select a sub-100µΩ shunt resistor, but these resistors tend to be larger and costlier than more common milliohm resistors. One alternative is to use magnetic-based solutions, but these are less accurate and have higher temperature drift than shunt-based solutions.
Overcoming these performance drawbacks will dramatically increase the cost and complexity of a magnetic solution as well.
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