Current sensor

product CS Zero-Flux Current Sensor

The CS Zero-Flux Current Sensor is a novel transducer that combines magnetic modulation and magnetic-balance principles. By exploiting the alternating saturation of a high-permeability core driven by an alternating excitation field, it rapidly transfers the primary current to the secondary winding according to the equal-ampere-turns law. The compensation current in the secondary winding generates a magnetic field that cancels that of the primary current, so the secondary current precisely represents the primary current. It accurately measures currents from 1 mA to 25 kA over a bandwidth from DC to 800 kHz. Based on ratio error and phase displacement, the sensors are divided into three series.

Type G Current Sensor: Accuracy better than 0.05 %, designed for high-precision measurement of various current signals in measurement and control applications, such as batteries, photovoltaic cells, and electric-vehicle charging stations.

Type P Current Sensor: Accuracy better than 20 μA/A, and phase displacement at reference frequency less than 1 minute of arc. It is intended for high-precision power measurement or any application demanding exact current phase information. Typical uses include rigorous testing and calibration of motors, variable-frequency drives, power transformers, new-energy vehicles, photovoltaic inverters, wind-power systems, fans/pumps, rail transit, integrated marine power and electric propulsion, and aircraft power supplies.

Type J Current Sensor: Accuracy better than 1 µA/A and phase displacement at the reference frequency less than 1 arc-minute, primarily serving as the current-measurement reference in calibration setups for variable-frequency electrical power metering.

Schematic Diagram of the CS Zero-Flux Current Sensor

The fundamental principle of the CS Zero-Flux Current Sensor relies on a novel magnetically-modulated zero-flux technique. A feedback current is driven to counteract the magnetic influence of the bus current on the toroidal core, thereby maintaining a zero-flux condition within the sensing core and realizing an almost ideal bus-current-to-output-current ratio.