Texas Instruments (TI) and Shengmeida have jointly developed a current sensor with a current detection error of <0.2%. The two sides presented the current sensor at TECHNOFRONTIER 2015 held in Messe Convention and Exhibition Center from May 20 to 22, 2015. The new product adopts fluxgate mode. Firstly, through the electrified wiring in the center of the ring core, the current is detected by a sensor called "fluxgate". Then, in order to make the magnetic field generated by the current zero, the feedback current is loaded to the compensation winding set by the magnetic core. Finally, the shunt resistance is used to detect the feedback current and to measure (calculate) the current through the wiring. Previously, most of the external Hall components were used for detection, and the detection error reached several percent. This time, by integrating fluxgate in special current sensor IC, the detection error is greatly reduced.
This TI is responsible for the development of current sensor IC, and Shengmeida is responsible for the development of core module "SC2912" with compensation windings. Current sensor IC and core module are not integrated design. A current sensor is made by installing current sensor IC on the printed board which forms wiring pattern, and then superimposing core module on it. "The current sensor IC and the shunt resistance will heat up," said Shengmeida's commentator. This method can radiate heat to the outside of the core module, so it can not only reduce the detection error, but also restrain the temperature drift and expand the temperature range.
For measurable current, SC2912 is 50A. However, if a larger core module is developed, it can also measure current above 50A. The corresponding frequency band is DC (DC) to 200 kHz. Mainly used in industrial motor drive equipment, industrial inverters, photovoltaic inverters, electric vehicles and hybrid electric vehicles.