These next-generation current sensing modules have combined the attributes of conventional passive shunt resistors with those normally associated with considerably more expensive and bulky closed-loop Hall Effect current sensors.
Each features a built-in precision amplifier, and they offer reinforced electrical isolation (up to 1500VDC), alongside impressive levels of stability and accuracy.
SSA Smart Shunt units exhibit ±0.1% sensing accuracy and ±0.1% linearity over their entire current range, with far less susceptibility to temperature drift. The need for routine calibration can therefore be avoided. They also have a rapid response time of less than 1.5μs. With an amplified analogue output and integrated protection, these current sensors can be placed on either the high or low side of a circuit, enabling easy integration. Their temperature range spans between -40°C and 125°C.
Riedon plans to offer a digital output as well, through I2C, RS232, Modbus and CAN interfaces (supporting both industrial and automotive installations).
The SSA Smart Shunt modules have been designed to be robust making them suitable for use in high-power (100A to 1000A) implementations, where harsh conditions may need to be dealt with - such as elevated temperature levels, heavy vibrations and electro-magnetic interference (EMI). Key examples include electric vehicle (EV) and hybrid-electric vehicle (HEV) traction inverters, AC/DC converters, uninterruptible power supplies, renewable energy generation sites and smart grid infrastructure.
“SSA Smart Shunt signifies a major step forward in shunt-based current sensing,” said Phil Ebbert, VP Engineering at Riedon. “Until now, despite clear drawbacks, such as the impact of electro-magnetic fields and temperature fluctuations on their accuracy, Hall Effect sensors have proved preferable in more challenging current measuring applications, as they are non-intrusive, possess intrinsic electrical isolation and support higher voltages. Conversely, the non-isolated nature of standard shunt resistors has held back their widespread deployment, even though they offer more accurate and operationally stable parameters.”
“By integrating isolation amplifiers, SSA Smart Shunt modules deliver superior accuracy and stability,” Ebbert conclude. “This opens up new current sensing opportunities, providing engineers with a compact and cost-effective alternative to specifying Hall devices.”
