PV Busbar Neutral Voltage Topology for PID Suppression
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Solution Overview
Problem
Existing PID effect suppression methods for photovoltaic systems are complex, prone to causing busbar voltage imbalances, and fail to effectively suppress the potential-induced degradation effect, which leads to significant power attenuation in battery modules.
Innovation Solution
A PID effect suppression system comprising a voltage source topology module connected to busbar neutral points with a common earth end, and a balanced circuit to adjust and balance busbar voltages, utilizing various construction methods including transformers, rectifier bridges, and adjustable circuits to ensure suppression voltage is at least half of the panel output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing PID suppression methods are used, then the PID effect can be suppressed, but the implementation process becomes more difficult and the structure of the suppression circuit becomes more complex
Solution Approach 1:
The patent combines the PID suppression function with the existing inverter system by integrating the voltage source topology module into the inverter's power circuit. The inverter's switching devices and power circuit components are utilized to generate the suppression voltage, merging two functions (inversion and PID suppression) into a single integrated system, thereby avoiding additional complex suppression circuits
Solution Approach 2:
The inverter system is designed to perform multiple functions: it serves as both the power conversion device for the photovoltaic system and the PID suppression device. The voltage source topology module within the inverter generates suppression voltage to counteract PID effects while maintaining its primary inversion function, making the system universal and eliminating the need for separate suppression equipment
2Reliability
If existing PID suppression methods are used, then the voltage to earth of photovoltaic panels can be adjusted, but busbar voltage imbalance occurs and normal system operation is influenced
Solution Approach 1:
The patent incorporates a control unit that monitors the voltage to earth of the photovoltaic panels and the state of the power circuit, and adjusts the working state of the switching devices accordingly. This feedback mechanism ensures that the suppression voltage is dynamically adjusted to maintain both PID suppression effectiveness and busbar voltage balance, preventing voltage imbalance while suppressing PID effects
Solution Approach 2:
The voltage source topology module uses dynamically controllable switching devices (such as IGBTs or MOSFETs) that can adjust their working state in real-time. This dynamic control allows the system to generate the required suppression voltage while maintaining balance in the power circuit, adapting to changing operating conditions without causing voltage imbalance
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 effectively suppresses PID effects by increasing the potential to earth of photovoltaic panels and balances busbar voltages, ensuring reliable operation and power output, with adjustable and flexible power sources for enhanced flexibility.
Implementation Method 1
the voltage source topology module includes a suppression circuit formed by connecting a transformer and an uncontrolled rectifier bridge
Implementation Method 2
the voltage of the power grid forms the suppression voltage after passing through the transformer and the uncontrolled rectifier bridge
Implementation Method 3
the balanced circuit is suitable for being connected to the voltage source topology module, and then the deviation voltage of the busbars is balanced
Data Source
AI summary
The present disclosure provides a PID (Potential Induced Degradation) effect suppression system. The PID effect suppression system includes a photovoltaic system, at least one voltage source topology module and a balanced circuit. The photovoltaic system is connected with a power grid. An output end of the voltage source topology module is connected with busbar neutral points of the photovoltaic system. A common earth end of the voltage source topology module is earthed, and then the potential to earth of a photovoltaic panel group in the photovoltaic system is improved through the suppression voltage output by the voltage source topology module, and the suppression voltage is greater than ½ of the output voltage of the photovoltaic panel group. Therefore, a PID effect of the photovoltaic system in operation can be effectively suppressed. When the voltage source topology module gets power from busbars, the balanced circuit can be connected between the output end of the voltage source topology module and the common earth end. If deviation occurs on the busbar voltage of the photovoltaic system, the balanced circuit is connected with the voltage source topology module, so that the deviation voltage generated by the busbars can be effectively balanced to ensure normal operation of the photovoltaic system under the suppression of the PID effect.