Transformer-Coupled Load Impedance Measurement Beyond Converter Bandwidth
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Solution Overview
Problem
Conventional industrial impedance spectroscopy systems are limited by the Nyquist rate of power converters, leading to restricted frequency bandwidth, significant power loss, and an inverse correlation between power level and switching frequency, making it difficult to determine high-frequency impedance data efficiently.
Innovation Solution
A load analysis signal generator using a multi-winding transformer with a de-biasing circuit and variable AC generator to generate high-frequency load analysis signals independently of the power converter's switching frequency, minimizing power loss and enabling wide frequency range impedance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power converters are used for impedance spectroscopy, then the system can operate at lower frequencies, but the frequency bandwidth is restricted by the Nyquist rate and power loss increases
Solution Approach 1:
The system separates the DC power supply function from the AC signal generation function. The DC power converter operates independently at low frequency to power the load, while a dedicated AC signal generator injects high-frequency analysis signals. This segmentation allows each component to operate in its optimal frequency range without being constrained by the other, resolving the contradiction between power loss and frequency bandwidth.
Solution Approach 2:
The patent introduces a coupling circuit as an intermediary between the DC power supply and the load. This coupling circuit enables the injection of high-frequency AC analysis signals through the DC power converter without requiring the power converter itself to switch at high frequencies. The intermediary transfers the high-frequency signal while the power converter maintains its low-frequency operation, minimizing power loss while extending frequency bandwidth.
2Adaptability or versatility
If the switching frequency of the power converter is increased to extend frequency bandwidth, then higher frequency impedance data can be obtained, but power loss increases significantly
Solution Approach 1:
The system divides the frequency generation function from the power conversion function. The AC signal generator produces high-frequency analysis signals independently, while the DC power converter operates at lower switching frequencies to power the load. This segmentation allows the system to access high-frequency impedance data without incurring the power losses that would result from increasing the power converter's switching frequency.
Solution Approach 2:
The patent replaces the mechanical switching operation of the power converter with an electronic AC signal generation system. Instead of relying on the power converter's switching frequency to determine the available frequency range, a dedicated AC signal generator electronically produces high-frequency analysis signals. This substitution eliminates the direct coupling between power conversion frequency and measurement frequency, allowing high-frequency measurements without increased power loss.
3Power
If there is an inverse correlation between power level and switching frequency, then high power operation is possible at low frequencies, but high-frequency impedance determination becomes difficult
Solution Approach 1:
The system segments the power delivery function from the signal injection function. The DC power supply provides high power at low frequencies to operate the load, while a separate AC signal generator injects high-frequency analysis signals for impedance measurement. This segmentation breaks the inverse correlation between power level and switching frequency, allowing both high power operation and high-frequency impedance determination to coexist.
Solution Approach 2:
The coupling circuit acts as an intermediary that allows high-frequency AC signals to be injected into the load while the DC power converter maintains high power output at low frequencies. This intermediary enables the decoupling of power level from switching frequency, resolving the difficulty of performing high-frequency impedance measurements during high power operation.
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 system achieves high-resolution impedance data over an extended frequency range with minimal power loss, allowing for accurate assessment of electrical, chemical, and biological properties of loads across various time scales.
Implementation Method 1
a transformer having at least one primary winding and at least one secondary winding; the at least one primary winding of the transformer being coupled in series between a direct-current (DC) power supply and the load
Implementation Method 2
the at least one second sensor comprises the hall-effect sensor, and the hall-effect sensor is configured to measure the DC flux bias in the transformer
Data Source
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Figure 2B
AI summary
Various embodiments are described herein for measuring the impedance properties of a load using load analysis signals. In one example embodiment, a transformer is provided which includes at least one primary winding, and at least one secondary winding. The at least one primary winding is coupled in series between a direct-current (DC) power supply and the load. A variable alternating-current (AC) voltage generator is coupled in-series to the at least one secondary winding, and is configured generate at least one load analysis signal for injection into the load. The impedance properties of the load may be determined for different frequencies in the load analysis signals.