Flyback Power Converter Input Voltage Compensation
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Solution Overview
Problem
Switched power converters face challenges in maintaining accurate output current due to changes in input voltage, particularly because they do not directly measure input voltage, leading to errors in constant current mode operation.
Innovation Solution
The power converter employs a method to indirectly sense input voltage by calculating a value based on the on-time and discharge time of the primary switch, using this value to compensate for input voltage changes and maintain constant output current without directly sensing the input voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the power converter operates in constant current mode without directly measuring input voltage, then the device complexity is reduced, but the measurement precision of output current deteriorates due to input voltage changes
Solution Approach 1:
The patent uses an intermediary approach by measuring a parameter that is correlated with input voltage (such as the voltage across a known impedance or a derived voltage signal) rather than directly measuring input voltage itself. This intermediary measurement allows the system to compensate for input voltage variations and maintain accurate output current control without requiring direct input voltage sensing, thus reducing device complexity while preserving measurement precision.
2Stability of the object's composition
If the power converter uses feedback or regulation loop to maintain stable output, then the output voltage stability is improved, but the ability to maintain accurate output current under input voltage changes deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the measured intermediary parameter (correlated with input voltage) is fed back to the control system. This feedback allows the controller to dynamically adjust the power converter operation to compensate for input voltage variations, maintaining both output voltage stability and output current accuracy simultaneously through coordinated control.
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 effectively controls output current by compensating for input voltage variations, ensuring accurate and stable output current in constant current mode operation without the need for additional input voltage sensing terminals.
Implementation Method 1
storing energy in a field of a transformer arranged for flyback operation
Data Source
AI summary
Operating power converters. At least some of the example embodiments are methods including: storing energy in a field of a transformer arranged for flyback operation, the storing by making conductive a primary switch coupled to a primary winding of the transformer; ceasing the storing of energy when a primary current through the primary winding reaches a predetermined value; measuring on time of the primary switch, the measuring creates a value indicative of on time; transferring energy from the field of the transformer; measuring discharge time of the energy from the field of the transformer during the transferring, the measuring of the discharge time creates a value indicative of discharge time; calculating a value indicative of input voltage of the power converter using the value indicative of on time and the value indicative of discharge time; and then compensating the predetermined value used in a subsequent storing energy step.