Transformer Load Analysis Signals for Broadband Impedance Measurement
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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 impedance properties over a wide frequency range.
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 broadband impedance spectroscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power converters are used for impedance spectroscopy, then the system can operate with standard components, but the frequency bandwidth is restricted by the Nyquist rate and significant power loss occurs
Solution Approach 1:
The system separates the power conversion function from the signal generation function. The power converter operates at fixed frequency to provide DC power, while a dedicated function generator circuit produces variable frequency AC signals for impedance spectroscopy. This segmentation allows each component to operate independently at its optimal frequency, eliminating the constraint where power converter switching frequency limits the measurement bandwidth.
Solution Approach 2:
A function generator circuit acts as an intermediary between the DC power supply and the load. This intermediary converts DC power into variable frequency AC signals specifically for impedance measurement, while the power converter continues to provide stable DC power without being constrained by measurement frequency requirements.
2Adaptability or versatility
If power converter switching frequency is increased to extend measurement bandwidth, then frequency range is improved, but power loss increases significantly
Solution Approach 1:
The system divides power conversion and signal generation into separate functional blocks. The power converter maintains fixed switching frequency for efficient power conversion, while the function generator independently produces variable frequency signals for broadband impedance measurement. This eliminates the direct coupling between power conversion efficiency and measurement frequency range.
3Power
If DC current is applied to transformer primary winding, then power is delivered to load, but DC flux bias is generated in transformer
Solution Approach 1:
The system extracts the DC component and AC component into separate pathways. DC current flows through the primary winding to deliver power to the load, while a separate de-biasing circuit generates compensating AC signals to cancel out the DC flux bias in the transformer core, preventing saturation and maintaining transformer efficiency.
Solution Approach 2:
The system uses feedback through the de-biasing circuit to detect and compensate for DC flux bias accumulation in the transformer. By monitoring the transformer core conditions and adjusting the compensating signal accordingly, the system maintains optimal transformer operation while delivering DC power to the load.
4Ease of operation
If single frequency AC signal is used, then the system is simpler to operate, but impedance properties over wide frequency range cannot be determined
Solution Approach 1:
The function generator circuit automatically performs periodic frequency sweeps, sequentially applying AC signals at multiple different frequencies to the load. This automated periodic action allows comprehensive impedance characterization across broadband frequencies while maintaining simple operation, as the system autonomously cycles through the frequency range without requiring manual intervention.
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
Enables high-resolution impedance data over an extended frequency range with minimal power loss, allowing for the assessment of various load properties across short and long 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
at least one first sensor coupled to the load, wherein the at least one first sensor is configured to measure at least one attribute of the load; a variable alternating-current (AC) voltage generator coupled in-series to the at least one secondary winding
Data Source
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.