Isolated Current Sensor With Digital Barrier Isolation
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Solution Overview
Problem
Current current measurement technologies face challenges in accurately measuring current in multiphase power systems due to lack of phase-to-phase isolation, susceptibility to magnetic interference, and electromagnetic interference, which affects the integrity of communication links and signal quality.
Innovation Solution
A digital barrier isolation system is introduced, which provides phase-to-phase isolation and reduces electromagnetic interference, allowing for accurate current measurement in multiphase systems by using a current sensor, such as a shunt, transformer, or Rogowski coil, coupled with an analog-to-digital converter and a barrier interface module, incorporating high-frequency transformers or capacitors for isolation, and encoding/decoding methods for error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a current shunt is used for current measurement, then the cost is reduced, but phase-to-phase isolation is lost leading to magnetic interference and cross-coupling issues
Solution Approach 1:
A digital isolation barrier is introduced as an intermediary component between the current shunt and the measurement circuitry. This barrier provides phase-to-phase isolation by blocking electromagnetic interference and cross-coupling while allowing digital signal transmission, thus enabling the use of cost-effective current shunts in multiphase systems without suffering from magnetic interference issues.
2Object-affected harmful factors
If a current transformer is used for current measurement, then phase-to-phase isolation is provided, but the device size and complexity increase
Solution Approach 1:
The isolation function is extracted from the current measurement component itself. Instead of using a bulky current transformer that provides isolation inherently, the patent separates the measurement function (current shunt) from the isolation function (digital isolation barrier), allowing each component to be optimized independently and reducing overall device complexity.
Solution Approach 2:
The patent replaces the electromagnetic isolation mechanism of current transformers with a digital isolation barrier that uses digital signal processing and communication protocols. This substitution eliminates the need for large magnetic cores and complex winding structures, significantly reducing device size and complexity while maintaining isolation effectiveness.
3Object-affected harmful factors
If digital barrier isolation is added to provide phase-to-phase isolation, then electromagnetic interference is reduced, but device complexity increases
Solution Approach 1:
The digital isolation barrier is designed to perform multiple functions simultaneously: providing phase-to-phase isolation, reducing electromagnetic interference, enabling bidirectional communication between isolated sides, and powering the isolated measurement circuitry. By consolidating these functions into a single component, the actual increase in device complexity is minimized despite the significant improvements in interference rejection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The digital barrier isolation enhances the signal-to-noise ratio, improves electromagnetic compatibility, reduces the need for redundant data, and shields communication links from interference, enabling accurate and reliable current measurement in both single-phase and multiphase power systems while minimizing the size and power consumption of measurement devices.
Implementation Method 1
The isolation barrier includes a high-frequency transformer, such as a pulse transformer which electrically isolates the host-side device from the line-side device
Implementation Method 2
The current sensor is used to measure current in a power line. The current sensor generates an analog indication of the current
Data Source
AI summary
The present disclosure includes a power measurement, circuit breaker or integrated protection system including isolated analog-to-digital modulators for measuring current using current sensors, such as, for example, current shunts, in a single or multiphase power system. In one embodiment, the modulators are divided into a line-side device with an analog-to-digital modulator and a host-side device including a decimation filter and a processor. In one embodiment, an isolation barrier, such as, for example, a pulse transformer, divides the lineside device from the host-side device.