Converter Output Current Measurement With Delta-Sigma Synchronization
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Solution Overview
Problem
Existing methods for analog-to-digital conversion of converter output current signals face challenges in achieving high temporal resolution for measurement duration synchronization, leading to coarse time quantization and limited synchronization quality, especially in industrial control loops where precise synchronization is required.
Innovation Solution
The method involves using a delta-sigma modulator to convert analog signals into a one-bit data stream, which is then processed by a digital filter with a series of integrators to produce a high-resolution digital representation of the signal, allowing for precise control of measurement duration and synchronization without the need for differentiators or decimation filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-pass filter with long time duration TD is used to achieve sufficient filtering effect, then filtering quality is improved, but temporal resolution of measurement duration is degraded
Solution Approach 1:
The patent segments the filtering process into two distinct stages: a first digital filter (low-pass filter) that performs analog-to-digital conversion and initial filtering, and a second digital filter that performs precise temporal measurement and synchronization. This segmentation allows each filter to optimize its function without compromising the other - the first filter ensures sufficient filtering quality while the second filter achieves high temporal resolution for measurement duration determination.
2Device complexity
If coarse temporal quantization TD is used for synchronization, then device complexity is reduced, but synchronization quality is degraded
Solution Approach 1:
The patent divides the synchronization function between two digital filters. The first digital filter handles the coarse temporal quantization with period TD for basic synchronization, while the second digital filter introduces fine temporal quantization with period TS for precise synchronization. This segmentation enables high synchronization quality without requiring complete redesign of the entire system, maintaining relative simplicity while achieving precision.
Solution Approach 2:
The patent makes the temporal quantization period dynamic by allowing the second digital filter to operate with a variable period TS that is shorter than TD. This dynamic adjustment enables the system to achieve fine temporal resolution for synchronization when needed, while maintaining the simpler coarse quantization structure for basic operations, thus balancing complexity and precision.
3Reliability
If measurement duration is set in whole multiples of TD, then filtering effect is ensured, but flexibility in setting start and end points is degraded
Solution Approach 1:
The patent segments the measurement interval definition into two components: the first digital filter ensures filtering effect through processing in multiples of TD, while the second digital filter enables flexible start and end point definition using fine temporal quantization TS. This segmentation allows the system to maintain reliable filtering while achieving adaptable measurement interval configuration for different application requirements.
Data Source
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AI summary
A method for processing a measured-value signal representing a value, determined in analog form, for the output current of a converter, and device for carrying out the method, the measured-value signals acquired by a sensor, especially including a shunt resistor, being supplied to a respective processing channel that has at least one delta-sigma modulator.