PV Midpoint Voltage Control for Polarization and PID Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Photovoltaic (PV) module reliability and service lifetime are compromised due to polarization effects, leading to power degradation and potential safety issues, particularly in crystalline silicon wafer-based systems, where reversible polarization affects n-type and p-type cells differently, and voltage-induced degradation mechanisms like Potential Induced Degradation (PID) are prevalent.
Innovation Solution
Implementing a power system with dynamic control methods that regulate reference voltages across PV strings, ensuring they remain within non-negative or non-positive limits relative to ground, using DC to DC converters and inverters to maintain symmetrical voltage conditions, thereby alleviating PID and extending the lifespan of PV modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If PV modules operate at higher voltages to increase power output, then power delivery capability is improved, but voltage-induced degradation (PID) and polarization effects worsen, reducing reliability and service lifetime
Solution Approach 1:
The patent implements dynamic voltage regulation by switching between different operational modes (normal mode and recovery mode) based on real-time polarization detection. The system dynamically adjusts the voltage applied to PV strings, transitioning from high voltage operation that maximizes power output to controlled voltage reversal or reduction that mitigates polarization degradation, thus resolving the contradiction between power output and reliability
Solution Approach 2:
The system changes the voltage parameter from positive to negative or from high to low based on detected polarization conditions. By monitoring voltage levels and polarization states, the controller adjusts the operating voltage parameter to prevent degradation while maintaining power output when conditions permit, directly addressing the trade-off between power and reliability
2Reliability
If dynamic control methods are implemented to regulate reference voltages and mitigate PID, then reliability and service lifetime are improved, but system complexity and control requirements increase
Solution Approach 1:
The patent employs feedback control by continuously monitoring the voltage across PV strings and detecting polarization conditions. The controller uses this feedback information to automatically adjust the reference voltage and switching states of power electronic components, implementing complex PID mitigation strategies through relatively simple feedback loops that compare actual voltage levels against target levels and make corrective adjustments
Solution Approach 2:
The system introduces an intermediary control layer that manages the complexity of voltage regulation. This control system acts as a mediator between the power electronic components (switches, converters) and the PV modules, translating complex mitigation requirements into simple switching commands and voltage adjustments, thereby reducing the apparent complexity at each interface while maintaining overall system reliability
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 enhances the reliability and service lifetime of PV modules by mitigating voltage-related degradation effects, ensuring efficient power delivery and reducing the risk of safety issues through adaptive and robust control of voltage conditions.
Implementation Method 1
a converter adapted to convert a source of power on a third input terminal and a fourth input terminal to a DC output voltage on a third output terminal
Implementation Method 2
A DC to AC inverter may include a first input terminal and a second input terminal. The first input terminal and the second input terminal may be connectable to the first output terminal and the second output terminal respectively
Implementation Method 3
a photovoltaic panel may connect to the input of the DC to DC converter
Data Source
AI summary
An apparatus may determine a parameter related to a voltage value at a midpoint terminal of a system power device, and may adjust a voltage applied to a second terminal of the system power device based on the parameter and a reference value. The second terminal may be different from the midpoint terminal.