Signal Evaluation Device Using Pulse Width Encoding
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Solution Overview
Problem
Existing devices for evaluating electrical input signals in switchgear for medium or high-voltage technology are limited to specific voltage ranges and types, making them ineffective for direct and alternating voltage signals with varying amplitudes, and require complex redesigns for galvanic isolation and digitization.
Innovation Solution
A device with multiple channels that converts input signals into pulsed signals with widths corresponding to voltage amplitudes, using a microprocessor to generate digital values without conventional A/D conversion, and includes features like rectifier circuits, scaling, and power supply circuits for self-supply and protection, enabling galvanic isolation and efficient evaluation of a wide range of input signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional A/D conversion methods are used for signal evaluation, then measurement precision is maintained, but device complexity increases and galvanic isolation becomes difficult to implement
Solution Approach 1:
The patent replaces conventional A/D conversion with a pulse width modulation approach where the voltage amplitude is encoded in the pulse width rather than digital bits. This substitution eliminates the need for complex A/D converters and galvanic isolation circuits, significantly simplifying the device while maintaining measurement capability through pulse width detection
Solution Approach 2:
The patent changes the parameter used to represent voltage amplitude from digital voltage levels (in conventional A/D) to time duration (pulse width). This parameter transformation allows the signal to carry amplitude information in a format that is easier to transmit and process without requiring complex conversion circuits
2Adaptability or versatility
If the device is designed to handle a wide range of voltage amplitudes and types, then adaptability improves, but device complexity increases
Solution Approach 1:
The patent creates a universal signal evaluation device that can handle both AC and DC voltages across a wide amplitude range (20-300V) using the same pulse width modulation circuitry. The single-channel design with pulse-based output serves multiple functions: evaluating different voltage types, achieving galvanic isolation, and providing standardized digital-compatible signals without requiring separate processing paths
3Reliability
If galvanic isolation is implemented between channels and microprocessor, then reliability improves, but ease of manufacture worsens
Solution Approach 1:
The patent replaces complex galvanic isolation circuits with a pulse width modulation interface where the microprocessor reads pulse widths through a simplified interface. This substitution maintains galvanic isolation reliability while dramatically easing manufacturing by eliminating the need for complex isolation circuitry between channels and the microprocessor
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 device can inexpensively and reliably evaluate a broad spectrum of input signals, including direct and alternating voltages, with galvanic isolation, allowing for efficient monitoring and control functions in switchgear systems.
Implementation Method 1
a signal processing device which is designed to generate a pulsed electrical signal with at least one pulse from the input signal or from a signal derived from the input signal, the width of the at least one pulse depending on the voltage amplitude of the input signal
Data Source
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Figure 5
AI summary
The device has input units (E1,E2,E1',E2') that receive an electrical input signal. A signal processing unit (18) produces a pulsed electrical signal with pulse derived from an input signal or from a derivative of input signal, based on the width of a pulse on voltage amplitude of input signal. A common microprocessor (30) controls the pulsed signals of channels or receives pulsed signals derived from signals of channels, and produces a digital value corresponding to the voltage amplitude of input signal of channel by evaluating a respective pulse width of received signals.