Comparator-Based AC Voltage Measurement Without Wide-Temp ADCs
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Solution Overview
Problem
Aircraft voltage measurement systems face challenges in achieving accurate AC voltage measurements over extended temperature ranges (-55° C. to +100° C) due to the high costs and limited availability of analog-to-digital converters (ADCs) required for wide temperature operating conditions, which also impose computational burdens and increase scrutiny for verification and certification.
Innovation Solution
A voltage measurement system that calculates AC peak voltage without using ADCs, employing a comparator, digital isolation circuits, a clock, buffer, and RC circuit, with an intelligence engine (such as an FPGA or DSP) executing an AC peak voltage computation algorithm, utilizing pulse width modulation (PWM) and timing signals to determine line frequency and pulse widths, thereby eliminating the need for premium ADCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ADCs are used for wide temperature range voltage measurement, then measurement accuracy is improved, but system cost increases
Solution Approach 1:
The patent extracts the ADC component from the voltage measurement system and replaces it with a comparator-based pulse width modulation approach. The ADC is completely removed from the bill of materials, eliminating the need for expensive wide-temperature-range ADCs while maintaining measurement functionality through alternative signal processing methods.
Solution Approach 2:
The patent substitutes expensive, specialized ADC components with inexpensive, widely-available comparator components that can operate across wide temperature ranges. The system uses standard off-the-shelf comparators and digital processing instead of premium ADCs, significantly reducing component costs while achieving the same measurement objective.
2Measurement precision
If ADCs are used for wide temperature range voltage measurement, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent replaces the analog-to-digital conversion mechanism with a digital pulse width modulation and timing measurement approach. Instead of using an ADC to directly convert analog voltage to digital values, the system uses a comparator to generate PWM signals whose duty cycle encodes the voltage information, which is then decoded through digital timing measurements.
3Measurement precision
If ADCs are used for wide temperature range voltage measurement, then measurement accuracy is improved, but verification and certification difficulty increases
Solution Approach 1:
The patent uses standard, widely-documented comparator components and digital logic elements that have well-established characterization data and verification procedures. These components are more readily available with published specifications and easier to verify compared to specialized ADCs, reducing the burden of verification and certification processes.
Data Source
AI summary
A voltage measurement system and method is provided. Aspects include a comparator having a positive and a negative input terminal, a processor configured to supply a reference voltage signal to the negative input terminal, wherein the positive input terminal receives an input voltage, setting the reference voltage signal to a zero voltage signal, determine a line frequency of the input voltage based on a timing signal from the comparator and determining a first pulse width of the input signal based on the timing signal, set the reference voltage to a PWM signal with a fixed duty cycle, receive the timing signal from the output of the comparator, determine a rising edge and a falling edge associated with the input voltage based on the timing signal, and determine a peak value of the input voltage based on a second pulse width between the rising and falling edge.