Photocoupler-Corrected Detection in Parallel Power Converters
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Solution Overview
Problem
Existing power conversion systems face challenges in achieving high accuracy for detecting output voltage and current, particularly in systems with multiple parallel-coupled power conversion apparatuses.
Innovation Solution
A power conversion apparatus and system that incorporate a signal generation circuit with a corrector, photocoupler, and output circuit to correct detection signals based on the current transfer ratio of the photocoupler, ensuring accurate detection of output voltage and current by reducing the influence of environmental variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a photocoupler is used to transmit detection signals in power conversion systems, then electrical isolation between circuits is achieved, but detection accuracy deteriorates due to variations in current transfer ratio caused by environmental factors
Solution Approach 1:
The patent implements a feedback mechanism where the control circuit monitors the actual current transfer ratio of the photocoupler (which varies with temperature and aging) and dynamically adjusts the detection signal accordingly. This closed-loop approach compensates for environmental variations and maintains accurate detection despite photocoupler characteristic changes
Solution Approach 2:
The patent changes the operating parameters of the detection system by introducing correction factors that account for photocoupler characteristics. The control circuit modifies detection signal parameters (gain, offset) based on measured photocoupler performance, enabling accurate detection despite variations in current transfer ratio caused by temperature and aging
2Productivity
If multiple power conversion apparatuses are parallel-coupled to increase power output, then productivity is improved, but control difficulty increases due to challenges in balancing output currents
Solution Approach 1:
The patent employs feedback control where each power conversion apparatus monitors its own output current and the currents of other parallel-coupled apparatuses. The control circuit adjusts switching duties of individual apparatuses based on real-time current measurements, automatically balancing the load distribution and maintaining equal output currents across all units
Solution Approach 2:
The patent creates an equipotential control system where all parallel-coupled power conversion apparatuses operate at the same control reference level. By synchronizing control signals and maintaining equal detection signal levels across all units, the system ensures balanced current sharing without requiring complex inter-apparatus communication or adjustment mechanisms
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 precise balancing and control of output currents and voltages across multiple power conversion apparatuses, enhancing detection accuracy and maintaining equal output levels.
Implementation Method 1
The light emitting device is configured to emit light at a luminance corresponding to the detection signal
Implementation Method 2
The light receiving device is configured to receive the light emitted by the light emitting device and to generate a light reception signal corresponding to the amount of the light received
Data Source
AI summary
A power conversion apparatus includes an input power terminal, an output power terminal, a power conversion circuit, a signal generation circuit, and a control circuit. The power conversion circuit converts supplied electric power and outputs the converted electric power. The power conversion circuit includes a sensor that generates a first detection signal corresponding to an output voltage or an output current. The signal generation circuit generates a second detection signal corresponding to the first detection signal. The control circuit controls operation of the power conversion circuit. The signal generation circuit includes a corrector, a photocoupler, and an output circuit. The corrector performs correction processing on the first detection signal. The photocoupler includes a light receiving device generating a light reception signal. The output circuit outputs the second detection signal corresponding to the light reception signal. The corrector performs the correction processing corresponding to a current transfer ratio of the photocoupler.