This week brought exciting news for fans of measuring current through resistive shunts. Sendyne Corp. has announced the new SFP100, a high precision current sensing IC that extends the range of accurate current measurements by at least an order of magnitude. With the Sendyne SFP100, ultra-low resistance and low-power consumption shunts can now be used in the field to measure currents ranging from kiloamperes to milliamperes with a precision that was previously available only in laboratory instruments.
The SFP100 was designed to address the requirements of battery monitoring in energy storage systems such as those used for EVs, grid storage and photovoltaic arrays, where large variations of current need to be monitored accurately. Errors in current measurement in these systems accumulate over time, leading to incorrect predictions of system energy capacity. In the past, using shunts in these applications forced system designers to make a trade-off between the desired accuracy and the excessive power consumption of the measurement system. The Sendyne SFP100 addresses this issue with a proprietary “Continuous Calibration” technology that minimizes current offset error.
Offset error determines the minimum current value for which the desired accuracy of current measurement can be achieved. The SPF100 reduces the maximum offset error to less than 150 nanovolts, regardless of the shunt resistance, without calibration and throughout the entire automotive temperature range of -40° C to 125° C. For example, using the Sendyne SFP100 and a 1 micro-ohm shunt, it is possible to measure up to 37,000 amperes with an offset current that is less than 150 mA in all ambient temperature conditions. In this scenario, the shunt’s heat dissipation at 1000 A would be just 1 W.
The SFP100 communicates to the host system over a simple serial interface – custom interfaces can be provided. The SFP 100 is the first release in the Sendyne Sensing Family of products.
Image by Andrew Hudgins, NREL 17070
Source: Sendyne Corp.