PV Direct-Current Switch Health Check via Voltage Difference
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Solution Overview
Problem
In photovoltaic systems, direct-current switches remain closed during non-power generation periods, increasing the risk of failure expansion in the power conversion apparatus if the switch itself fails undetected, as they are not routinely checked for operation.
Innovation Solution
A control apparatus that includes a voltage acquisition unit, operation control units, a clocking unit, and a soundness determination unit to regularly check the direct-current switch's operation and soundness by measuring voltage differences and elapsed time, determining switch normalcy, and controlling its state to prevent failure expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the direct-current switch remains closed during non-power generation periods, then the system maintains readiness for power generation, but the risk of undetected switch failure increases, potentially leading to failure expansion in the power conversion apparatus
Solution Approach 1:
The system uses its own operational characteristics (voltage differences across the switch) to self-diagnose switch health. The monitoring unit measures voltage differences that naturally occur during switching operations, eliminating the need for external diagnostic equipment and enabling the system to autonomously detect switch failures.
Solution Approach 2:
The system performs preliminary detection of switch failures by measuring voltage differences during normal operations before actual failure occurs. This allows the system to identify potential switch problems early and take preventive actions, such as alerting operators or automatically isolating affected components.
2Productivity
If the direct-current switch is opened only when failure is detected, then the system maintains continuous operation, but the switch itself may fail undetected and cannot be opened when needed
Solution Approach 1:
The monitoring unit continuously measures voltage differences across the switch and provides feedback about switch health status. This feedback mechanism enables the system to detect switch failures while maintaining operational continuity, allowing operators to respond to alerts and perform maintenance before actual failures occur.
Solution Approach 2:
The patent replaces mechanical testing methods (physical switch actuation) with electrical measurement methods (voltage difference measurement). This substitution allows for non-intrusive, continuous monitoring of switch health without disrupting normal operations or requiring manual intervention.
3Reliability
If routine checking of the direct-current switch is implemented, then failure expansion is suppressed, but the system requires additional monitoring components and processing
Solution Approach 1:
The monitoring unit serves multiple functions: it measures voltage differences for switch health detection, identifies failure modes, and provides diagnostic information. By making the monitoring system multi-functional, the patent reduces the need for separate dedicated components for each function, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The patent combines the switch monitoring function with existing system components. The monitoring unit integrates with the power conversion apparatus control system, sharing processing resources and communication infrastructure. This merging approach enables routine switch checking without requiring completely separate monitoring hardware and software systems.
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 solution effectively suppresses failure expansion in the power conversion apparatus by routinely checking and managing the direct-current switch's operation, ensuring its normalcy and preventing continuous power flow that could exacerbate failures.
Implementation Method 1
a voltage acquisition unit configured to acquire a first direct-current voltage value as a voltage of the solar panel and a second direct-current voltage value as a voltage of the direct-current capacitor
Data Source
AI summary
A control apparatus including a first operation control circuit configured to open a direct-current switch when a power conversion apparatus is in a waiting state and a first direct-current voltage value is greater than a predetermined first threshold, a clocking circuit configured to, when the direct-current switch is opened, clock an elapsed time after the direct-current switch is opened, and a soundness determination circuit configured to calculate a first difference voltage value that is a difference between the first direct-current voltage value and a second direct-current voltage value when the power conversion apparatus is in the waiting state and the direct-current switch is opened, and the elapsed time is greater than or equal to a predetermined first time, to determine that the direct-current switch is abnormal when the first difference voltage value is less than or equal to the predetermined second threshold.