DC-CT

DC-CT Innovation

About

DC-CT represents an innovative principle of isolated measurement of DC and AC currents. Within a magnetic core, magnetic flux can only be measured if it is non-constant, changing, or alternating. Since a DC current generates a constant magnetic flux the innovative principle redistributes this flux among two or more paths periodically in a single core. If we observe this magnetic flux from one path only it appears alternating and is therefore easily measured by a simple winding, which voltage is proportional to the measuring current.

This was achieved by inventing a current-controlled variable reluctance - a vital component, composed of a kind of infinity winding, embedded into a gap-less core retaining all of the good properties of high permeability materials. This new type Platiše Flux Sensor is named after the inventor Uroš Platiše.

Comparing this principle to widely used Hall-based sensors inserted into a magnetic core, the DC-CT solution does not create any air-gap, retaining very high sensitivity and immunity to external magnetic fields. In addition, the new DC-CT sensing principle is temperature independent.

Comparing this principle to the most widely used high-end flux-gate transducers, a flux-gate method adds energy to the core to alternate the flux between the maximum and minimum operational limits of the core consuming a significant amount of energy. Value of the measuring current can be extracted from the 2nd harmonics, pulse-width-modulation in self-oscillating solutions, or other methods.

High-end flux-gate solutions require three cores instead of just one, as in the case of the DC-CT current transducer. Two of them are required for sensing, operating in opposite direction to reduce injected noise, and the third is used to extend the AC bandwidth. Flux-gate resets a core repeatedly, while the DC-CT on request only to demagnetize the core.

Comparison table of DC-CT versus other current sensor types:

Technology Type Isolated Current Range AC Bandwidth Linearity Accuracy Temperature Drift Power Consumption
DC-CT DC/AC Yes High High Excellent Very High Very Low Medium
Fluxgate DC/AC Yes High High Excellent Excellent Low High
Hall DC/AC Yes High Medium Medium Medium High Low / Medium
Shunt DC/AC No Medium Medium Good High Medium High
Rogowsky AC Yes High High Good Medium Low Low
CT AC Yes High Medium Medium Medium Low Low

DC-CT is, therefore, energy-efficient, of compact size, low noise, and cost-effective. Existing products range from 2 A and up to 2000 A, up to 1 MHz bandwidth, with target accuracy from 0.1% down to 0.01%. Other potential uses include DC/AC residual current sensors of class B+.

Dewesoft XHS DC-CT (DOT)

Products Embedding the DC-CT ® Technology

  • High-end products are embedded within the Dewesoft Sirius XHS with measurement range up to 2000 A with sensor size of 50 x 50 mm