Photovoltaic System PID Suppression via Inverter Bypass Circuit
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Solution Overview
Problem
Existing photovoltaic systems face challenges in preventing potential induced degradation (PID) due to sodium ion diffusion, with existing solutions either insufficient in preventing PID or requiring costly and complex circuit designs.
Innovation Solution
A photovoltaic system incorporating a solar cell module array, a rechargeable battery, and a power conditioner with an inverter, bypass electric path, and switching circuits that apply a positive potential to the positive electrode and control the negative electrode's potential to prevent sodium ion infiltration during non-power generation periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a direct-current power source is used to apply voltage to the negative electrode to prevent PID, then PID prevention effectiveness is improved, but system cost and circuit complexity increase
Solution Approach 1:
The inverter is designed to perform multiple functions: both power conversion (DC to AC) and PID prevention through the voltage application circuit. The same inverter hardware that converts solar power to grid-compatible AC power also serves as the power source for applying positive voltage to prevent PID, eliminating the need for a separate dedicated power source.
Solution Approach 2:
The patent combines the PID prevention function with the existing inverter circuit by introducing a bypass electric path that connects the inverter output to the positive electrode. This merges two previously separate functions (power conversion and PID prevention) into a single integrated system, reducing overall system complexity.
2Reliability
If a separate direct-current power source is added to prevent PID, then PID prevention effectiveness is improved, but system cost increases
Solution Approach 1:
The inverter is designed to perform multiple functions: both power conversion (DC to AC) and PID prevention through the voltage application circuit. The same inverter hardware that converts solar power to grid-compatible AC power also serves as the power source for applying positive voltage to prevent PID, eliminating the need for a separate dedicated power source.
Solution Approach 2:
The system uses its own inverter output to provide the voltage needed for PID prevention, rather than requiring an external power source. The inverter essentially serves itself by providing both the power conversion function and the protective voltage application function, making the system self-sufficient.
3Productivity
If the first switching circuit is kept closed to maintain electrical connection, then power conversion efficiency is improved, but sodium ion diffusion increases during non-power generation periods
Solution Approach 1:
The switching circuit is designed to dynamically change its state based on operational conditions. It closes during power generation to enable efficient power conversion, and opens during non-power generation periods to prevent sodium ion diffusion. This dynamic switching capability allows the system to optimize performance while preventing degradation.
Solution Approach 2:
The switching circuit operates periodically, alternating between closed state (during power generation) and open state (during non-power generation). This periodic switching ensures that the electrical connection is maintained only when needed for power conversion, while preventing harmful sodium ion diffusion during idle periods.
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 configuration effectively reduces the likelihood of PID occurrence without the need for additional power sources, maintaining a simple system design and low power consumption while enhancing power generation efficiency.
Implementation Method 1
an inverter that converts a direct current supplied from the solar cell module array or a direct current supplied from the rechargeable battery into an alternating current
Implementation Method 2
a voltage application circuit that induces a potential of the positive electrode of the solar cell module array toward a positive potential
Implementation Method 3
sodium ions (Na+) contained in a glass substrate of the solar cell module diffuse and infiltrate an electrode of a solar cell whose potential has become negative and finally diffuse and infiltrate a photoelectric conversion substrate
Implementation Method 4
a solar cell module array
Data Source
AI summary
Provided is a photovoltaic system wherein potential induced degradation (PID) is simply and efficiently suppressed. This photovoltaic system is provided with a bypass electric path that connects an inverter and a positive electrode of a solar cell module array to each other by being connected in parallel to a first electric path between the inverter and the solar battery module array. The bypass electric path is provided with a second switching circuit, and a first switching circuit is provided to an electric path between the inverter and a negative electrode of the solar cell module array, the electric path being a part of the first electric path.