Dual-Mode Current Sensor Using Segmented Resistor and Transformer Circuits
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Solution Overview
Problem
Existing measurement systems face challenges in accurately detecting both short bursts and steady-state levels of energy consumption over a high dynamic range, requiring expensive and high-performance components to handle both low and high current levels, which is costly and complex.
Innovation Solution
A device comprising a resistor-based measuring circuit for direct current and a transformer-based measuring circuit for alternating current, combined with inverters and a signal combiner to provide a digital signal representing the electrical current, allowing for cost-effective measurement of high dynamic ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single high-performance resistor-based measuring circuit is used to measure both low and high current levels, then measurement precision is improved, but device complexity and cost increase due to requiring high linearity, low noise, and high dynamic range components
Solution Approach 1:
The patent divides the measuring circuit into two separate circuits: a resistor-based measuring circuit for DC current components and a transformer-based measuring circuit for AC current components. Each circuit is optimized for its specific function, avoiding the need for a single complex high-performance circuit to handle both types of measurements simultaneously.
Solution Approach 2:
The patent creates a universal measuring device that can measure both DC and AC current components through the combination of two specialized circuits. The resistor-based circuit handles DC measurements while the transformer-based circuit handles AC measurements, together providing comprehensive current measurement capability.
2Measurement precision
If a high sample rate Analog-to-Digital converter is used to capture short bursts of energy consumption, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent segments the measurement function into DC and AC components, allowing each Analog-to-Digital converter to be optimized for its specific signal type. This enables the use of lower sample rate converters for DC measurements while higher sample rate converters are only needed for AC burst detection, reducing overall system cost.
3Measurement precision
If a large resistance value is used in the resistor-based measuring circuit to detect very low currents, then measurement precision is improved, but the maximum current measurement capability is limited due to high voltage drop
Solution Approach 1:
The patent separates DC and AC current measurement functions into different circuits. The resistor-based circuit uses optimized resistance for DC measurements, while the transformer-based circuit handles AC measurements including current peaks, allowing each circuit to be optimized for its specific current range without compromise.
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 solution enables accurate measurement of both low and high current levels with improved performance at reduced cost and complexity, effectively handling high dynamic ranges by aggregating bandwidth-dependent hardware elements.
Implementation Method 1
a current transformer comprising a primary coil, connected in series with the resistor of the resistor based measuring circuit, and a secondary coil
Data Source
AI summary
The disclosure relates to a device for measuring electrical current in an electrical conductor (2), the device comprising: a measuring circuit configured to be connected to the electrical conductor, the measuring circuit comprising: a resistor based measuring circuit comprising a resistor (10), a transformer based measuring circuit comprising a current transformer (20) comprising a primary coil (20a), connected in series with the resistor (10) of the resistor based measuring circuit, a first inverter (12) configured to transform a first digital signal using a transfer function being an inverse of a transfer function representing the resistor based measuring circuit; a second inverter (22) configured to transform a second digital signal using a transfer function being an inverse of a transfer function representing the transformer based measuring circuits; and a signal combiner (5) configured to combine the transformed first and second digital signals, thereby providing a digital signal representing the electrical current in the electrical conductor. The disclosure also relates to a method for measuring electrical current in an electrical conductor.