PCB-mount, ±50A high-precision current sensor

July 15, 2013 // By Graham Prophet
ALPS Green Devices has developed the “GCBC Series” high-precision current sensor, achieving compact size, light weight and low loss. Samples will be made available from July 2013.

Attention in energy saving is focusing on inverters, which can reduce power consumption through fine control of motor operation and which are expected to have benefits even for equipment that is not motor-driven, for example by helping to create high-efficiency power conditioners. A key device for achieving high-precision inverter control is the current sensor.

Current sensors generally employ one of two approaches-measurement based on shunt resistance, or measurement of the magnetic flux generated around a current. The DC current transformer (DCCT) approach employing flux measurement is widely used to achieve high-precision detection while keeping down costs. The DCCT approach is generally used with magnetic elements that have low sensitivity and therefore a magnetic core is required to concentrate flux around the current. This results in larger and heavier equipment designs. In addition, existing current sensors became hot quickly due to high resistance in the primary conductor, leading to associated power loss.

The GCBC Series is a current sensor for PCB mounting and is the smallest and lightest in the industry. Use of a proprietary high-sensitivity magnetic sensor element (GMR element) eliminates the need for a core to concentrate magnetic flux, enabling compact dimensions of 13.4 × 15.7 × 7.2mm and weight of 3g. Magnetic control plates positioned around the sensor element ensure both high sensitivity and resistance to outside disturbance.

Resistance in the primary conductor is also the industry’s lowest at 60 µΩ, a 40% reduction compared to existing current sensors. This reduces conductor heat generation, helping to lower power loss associated with current measurement. The GCBC Series supports a maximum continuous current up to ±50A and ALPS Green Devices is developing sensors that will detect currents of up to 150A.

ALPS, www.alps.com/products/e/npv_product/130712_GCBC/GCBC_E.PDF