Power Converter Voltage Control for PV Array Overload
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Solution Overview
Problem
Power converters in solar energy systems face tripping or damage when the DC to AC ratio exceeds 1, due to excessive power from PV arrays, which is undesirable as it limits the system's operational flexibility and reliability, especially under varying environmental conditions.
Innovation Solution
A system controller is used to select between a first and second reduced power operating point for the power converter, adjusting the PV array voltage to match the desired output power level, thereby preventing converter overload and allowing operation with a wider range of PV arrays and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the DC to AC ratio is increased to maximize power output, then the amount of time the output power level is at the desired level is maximized, but the power converter is more likely to trip or be damaged
Solution Approach 1:
The system dynamically adjusts the PV array operating point between two reduced power operating points based on real-time conditions. The controller monitors the available power from the PV array and selects appropriate operating points to maintain converter operation within safe limits while maximizing power output, thereby resolving the contradiction between productivity and reliability
Solution Approach 2:
The system changes the operating parameters of the PV array by selecting between different reduced power operating points (different voltage and power levels) to prevent converter overload. This parameter adjustment allows the system to maintain high productivity while ensuring converter reliability under varying environmental conditions
2Productivity
If the PV array is designed to produce more power than the converter rating, then the system can operate at desired power levels for longer periods, but the converter is more likely to trip or be damaged
Solution Approach 1:
The system performs preliminary action by pre-defining two reduced power operating points for the PV array that are specifically designed to prevent converter overload. Before the converter can trip or be damaged, the controller has already established safe operating parameters, allowing the system to maintain desired power output levels while protecting the converter
Solution Approach 2:
The controller acts as an intermediary between the high-power PV array and the rated-power converter. It mediates the power flow by selecting appropriate reduced operating points for the PV array, thereby enabling the system to utilize the PV array's full power capability while protecting the converter from damage
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 maintains a stable power output, prevents converter tripping, and enables operation over a broader range of conditions, including cold weather and high irradiance, while utilizing PV arrays with higher power capabilities than the converter rating.
Implementation Method 1
Solar energy in the form of sunlight may be converted to electrical energy by solar cells. A more general term for devices that convert light to electrical energy is 'photovoltaic cells.'
Data Source
AI summary
A power conversion system for providing power to an electrical grid is described. The power conversion system includes a power converter coupled to a photovoltaic (PV) array and configured to control a PV array voltage. The power conversion system also includes a system controller communicatively coupled to the power converter and configured to select from a first reduced power operating point and a second reduced power operating point when a power available from the PV array is greater than a rated output power of the power conversion system.