Power Converter Output Impedance Control for Accurate Status Sensing
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Solution Overview
Problem
Existing methods for determining the working status of power conversion apparatuses, such as photovoltaic optimizers, suffer from low accuracy due to voltage detection methods, which are prone to errors from voltage deviations and wire drops, making it difficult to ensure precise installation and operation.
Innovation Solution
A power conversion apparatus comprising a power conversion circuit, an impedance adjustable circuit, and a control circuit that adjusts the output impedance based on the apparatus's status, distinguishing between faulty and normal conditions by setting different impedance states, allowing for more accurate representation and detection of the working status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If voltage detection method is used to determine working status, then the method is simple to implement, but the measurement precision is low due to voltage deviations and wire drops
Solution Approach 1:
The patent changes the detection parameter from voltage to impedance. By detecting the impedance of the power conversion apparatus instead of voltage, the system avoids errors caused by voltage deviations and wire drops. The impedance detection method provides more accurate working status determination while maintaining implementation feasibility through standard measurement equipment.
2Ease of manufacture
If output voltage is controlled to be 1V for testing, then the testing method is simple, but the manufacturing precision is insufficient to ensure actual control precision
Solution Approach 1:
The patent changes the test parameter from output voltage to output impedance. Instead of controlling and measuring voltage at 1V, the system measures impedance which remains stable and accurate regardless of voltage control variations. This eliminates the precision problems associated with low-voltage control while keeping the testing process straightforward.
3Ease of operation
If voltage detection is used for series-connected optimizers, then the detection method is straightforward, but the measurement precision deteriorates due to accumulation of voltage deviations
Solution Approach 1:
The patent changes the measurement parameter from voltage to impedance for series-connected optimizers. By measuring impedance instead of voltage, the system avoids the accumulation of voltage deviations that occur when multiple voltage measurements are summed. Impedance measurement provides accurate results for each individual optimizer and for the series connection as a whole, while maintaining operational simplicity.
Data Source
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AI summary
A power conversion apparatus and a method for controlling an output impedance of a power conversion apparatus are provided to resolve a prior-art problem of relatively low accuracy of a method for determining a working status of a power conversion apparatus. The method includes: adjusting the output impedance of the power conversion apparatus to a first impedance when the power conversion apparatus does not satisfy a start condition; or adjusting the output impedance of the power conversion apparatus to a second impedance when the power conversion apparatus satisfies a start condition, where the first impedance is not equal to the second impedance.