Adaptive Input Scaling for Isolated Current and Voltage Measurement
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Solution Overview
Problem
Current measurement devices in industrial automation and control systems, particularly in substation or power grid automation, face challenges in achieving a high dynamic range with galvanic isolation, requiring multiple hardware paths and increasing costs, and struggle to handle instantaneous overcurrent signals and waveform artefacts effectively.
Innovation Solution
A device and method utilizing a single input channel with an ADC and discrete components like switches and resistors, employing a feedback loop with hysteresis to adjust the scaling factor dynamically, allowing for high dynamic range measurement without integrated adjustable gain amplifiers and maintaining operator safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple hardware paths are used to achieve high dynamic range measurement, then the measurement range is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges multiple measurement paths into a single input channel by dynamically switching between different gain stages of an integrated adjustable gain amplifier within the ADC device, eliminating the need for separate hardware paths for different measurement ranges
Solution Approach 2:
The patent implements dynamic range adjustment by automatically switching between multiple gain stages based on the input signal level, allowing a single ADC to adaptively handle both small and large signal ranges without requiring multiple fixed-gain hardware paths
2Reliability
If galvanic isolation is implemented in ADCs, then operator safety is improved, but the available bit rate and dynamic range are reduced
Solution Approach 1:
The patent combines galvanic isolation with an integrated adjustable gain amplifier within the ADC device, allowing the isolated ADC to maintain high dynamic range measurement capability through internal gain switching without requiring multiple isolated input channels
Solution Approach 2:
The patent makes the isolated ADC multi-functional by integrating an adjustable gain amplifier that can dynamically adapt to different signal ranges, allowing a single isolated ADC to perform both high-voltage and low-voltage measurements that previously required multiple specialized channels
3Adaptability or versatility
If multiple input channels are used for different measurand ranges with galvanic isolation, then the measurement capability is improved, but the cost increases significantly
Solution Approach 1:
The patent creates a universal isolated ADC that can handle multiple measurand ranges through an integrated adjustable gain amplifier, replacing multiple specialized isolated input channels with a single multi-functional device
Solution Approach 2:
The patent merges the functions of multiple isolated input channels into a single isolated ADC with internal gain switching capability, consolidating what would have been separate hardware paths into one cost-effective solution
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 high dynamic range current and voltage measurement with galvanic isolation in a single input channel, reducing costs and improving measurement quality and safety, while effectively handling instantaneous overcurrent signals and waveform artefacts.
Implementation Method 1
employing a feedback loop with hysteresis to adjust the scaling factor dynamically
Data Source
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AI summary
The present invention relates to a device and a method for measurement of electrical signals in an industrial automation and control system. The device comprises an input circuit, configured to receive an electrical input signal (100), scale the electrical input signal by a scaling factor and to set the scaling factor according to a scaling signal (110), an Analog-to -Digital Converter, ADC (220), which is electrically connected to the input circuit, wherein the ADC is configured to convert the scaled electrical input signal (103) into an intermediate digital signal (120), and a first signal path (211), connected to an digital end of the ADC, configured to create the scaling signal (110) and to send the scaling signal (110) to the input circuit, wherein, based on the intermediate digital signal of a sample period and the scaling factor of the sample period, the scaling factor for a subsequent sample period is set.