Transformer Iron Core Tester Using Hysteresis Control
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Solution Overview
Problem
The existing methods for evaluating transformer iron core non-linear characteristics and quality checking are time-consuming and complex, requiring demagnetization, expensive equipment, and difficult comparisons across different manufacturers, dimensions, and constructions, especially when dealing with pulse-form output from inverters, which are common in modern transformer applications.
Innovation Solution
A device called the Transformer Iron Core Tester uses a hysteresis current controller with a regular H-bridge inverter for pulse excitation, allowing quality evaluation without demagnetization and expensive equipment, by measuring reactive power and cross-sectional area, and is capable of comparing cores with different dimensions and constructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard measuring methods (IEC 60404-2, ASTM A772) are used to evaluate transformer iron core quality, then measurement accuracy is improved, but the process becomes time-consuming and requires expensive specialized equipment
Solution Approach 1:
The patent replaces expensive, specialized measuring equipment with a simple microcontroller-based system using readily available components (Arduino Uno, current sensor, H-bridge inverter). This disposable-like approach uses inexpensive, easily replaceable components to achieve accurate measurements without requiring costly laboratory-grade instruments.
Solution Approach 2:
The patent substitutes complex mechanical/electrical testing systems with a digital control system based on microcontrollers. The Arduino-based controller automatically manages the H-bridge inverter, performs measurements, and processes data, replacing traditional manual or semi-automated mechanical testing apparatus with intelligent digital control.
2Reliability
If demagnetization process is performed before testing, then measurement reliability is improved, but the process becomes more time-consuming and complex
Solution Approach 1:
The patent incorporates demagnetization as a preliminary action that is automatically performed before the main measurement process. The microcontroller system executes a demagnetization sequence using the H-bridge inverter to gradually reduce the magnetic field to zero, ensuring the core is properly prepared for accurate measurement without requiring separate manual demagnetization steps.
Solution Approach 2:
The testing system performs demagnetization automatically as part of its own operation. The microcontroller-controlled H-bridge inverter generates the necessary reverse polarity pulses to demagnetize the core, eliminating the need for external or separate demagnetization equipment and making the process self-contained.
3Measurement precision
If multiple standards are used for quality checking, then measurement comprehensiveness is improved, but device complexity and difficulty of comparison are increased
Solution Approach 1:
The patent creates a universal testing platform that can evaluate different types of transformer cores (EI, toroidal, pot cores) with various dimensions and constructions using a single microcontroller-based system. The H-bridge inverter and measurement circuitry are designed to accommodate different core geometries, making the equipment multi-functional rather than requiring separate specialized devices for each core type.
Solution Approach 2:
The system automatically adapts measurement parameters based on the specific core being tested. The microcontroller adjusts excitation frequency, voltage levels, and measurement thresholds according to the core's characteristics, allowing comprehensive quality assessment across different standards while maintaining a single unified testing apparatus.
4Reliability
If individual quality check of each transformer core is performed, then quality assurance is improved, but productivity is reduced
Solution Approach 1:
The patent enables continuous quality checking by automating the entire measurement process. The microcontroller system continuously performs excitation, measurement, data processing, and evaluation without manual intervention between samples. This continuous automated operation maintains thorough quality assurance while significantly increasing manufacturing throughput compared to manual individual checking.
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
This solution simplifies the quality evaluation process, reduces costs, and enables efficient comparison of transformer cores, ensuring better core quality assessment without the need for specialized equipment, and can test cores during assembly, including those with varying lamination thicknesses and air gaps.
Implementation Method 1
A device called the Transformer Iron Core Tester uses a hysteresis current controller with a regular H-bridge inverter for pulse excitation
Implementation Method 2
The invention subject, i.e. Transformer Iron Core Tester, switches the supply voltage by the H-bridge inverter with the help of the hysteresis controller when the primary current reaches the defined maximum value
Implementation Method 3
The Transformer Iron Core Tester evaluates the iron core quality and the magnetic characteristic of analyzed magnetic circuit on the basis of determined operating frequency f, core cross-section area A Fe as well as the measured reactive power Q
Data Source
Figure 1~2
AI summary
The tester and the procedure of testing to determine the quality of magnetic circuits is based on pulse excitation and hysteresis control of primary current. The magnetic characteristic of the tested transformer iron core is evaluated on the basis of measured frequency of excitation and measured reactive power. The corresponding working point and tester operating range is chosen by changing the number of primary winding turns and by selecting switching current and voltage. All tests are performed by the standard existing inverter, so that there is no need for an expensive additional testing equipment. Transformer core testing is quick, effective and universal. The tests of already built-in cores are also possible. The entire magnetic circuit is evaluated by the described procedure taking into account influence of many factors, such as the type of material, lamination tickness, damages, treatment of the air gap, irregularities during construction, etc.