Flyback Converter Voltage Detection via Secondary Sensing
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Solution Overview
Problem
Current voltage measurement methods in electric drive systems, such as those in electric vehicles, require expensive components with low tolerances for precise detection, leading to high costs and space inefficiencies, particularly in the intermediate circuit of current converters.
Innovation Solution
A device and method utilizing a flyback converter with a transformer and switching element, where the voltage sensor is placed on the secondary side to calculate the primary voltage based on the switching state, integrating voltage measurement within the existing flyback converter for the control electronics, eliminating the need for a separate measurement circuit and allowing for cost-effective and space-saving voltage detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage measurement circuits are used with low-tolerance components, then measurement precision is improved, but device cost and space requirements increase
Solution Approach 1:
The patent merges the voltage measurement function with the existing flyback converter circuit by placing the voltage sensor on the secondary side and using the transformer turns ratio for voltage calculation. This integration eliminates the need for separate high-precision voltage measurement circuits, reducing component count and device complexity while maintaining measurement accuracy through the relationship U1/U2 = N1/N2.
Solution Approach 2:
The flyback converter transformer is given dual functionality: it serves both as the power conversion element and as the basis for voltage measurement. By utilizing the transformer's inherent turns ratio and placing a sensor on the secondary side, the same magnetic component enables both voltage transformation and voltage detection, reducing overall device complexity.
2Measurement precision
If separate voltage measurement circuits are implemented, then measurement precision is improved, but space requirements increase
Solution Approach 1:
The voltage measurement functionality is merged into the existing flyback converter structure. The voltage sensor is placed on the secondary side of the transformer, and the measurement circuit shares the transformer and control electronics with the power conversion function, thereby eliminating the need for separate measurement circuitry and reducing PCB space requirements.
Solution Approach 2:
The system uses its own internal components (transformer turns ratio and secondary-side voltage sensor) to perform voltage measurement, rather than requiring external dedicated measurement circuits. The flyback converter's existing structure provides the measurement capability, making the system self-sufficient and space-efficient.
3Measurement precision
If high-precision components are used for voltage detection, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive low-tolerance components with more economical alternatives. By using the transformer turns ratio (which is inherently precise due to manufacturing constraints of the magnetic component) and a standard voltage sensor on the secondary side, the system achieves accurate voltage measurement without requiring costly high-precision resistors or dedicated measurement ICs.
Solution Approach 2:
The measurement approach changes from directly measuring high voltage with expensive components to measuring a scaled-down voltage on the secondary side and calculating the primary voltage using the transformer turns ratio. This parameter transformation enables the use of lower-cost sensors while maintaining measurement precision through the mathematical relationship U1/U2 = N1/N2.
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 approach provides a cost-effective and precise method for determining voltage ratios on the high-voltage side of electric drive systems, offering additional safety through dual measurement methods and utilizing existing components, thereby reducing component costs and space requirements.
Implementation Method 1
the flyback-converter transformer has a primary side and a secondary side... sensing a secondary voltage on the secondary side of the flyback-converter transformer... calculating a primary voltage which corresponds to a voltage on the primary side
Data Source
AI summary
The invention relates to a device and to a method for determining a voltage. The voltage to be determined is a direct voltage at the input of a flyback converter. The flyback converter comprises at least a flyback-converter transformer and a switching element on the primary side of the flyback-converter transformer. In order to determine the voltage at the input of the flyback converter, a voltage on the secondary side of the flyback-converter transformer is sensed and evaluated in correlation with the switching state of the switching element on the primary side.