Distributed PV Module Voltage Control via Bus Detection
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Solution Overview
Problem
Efficiently transferring and combining Direct Current (DC) power from solar panels or other DC sources to an Alternating Current (AC) power grid is challenging due to variable output voltages and currents, which are not fixed and can fluctuate unpredictably, making it difficult to maintain efficient conversion and combination.
Innovation Solution
A system comprising multiple photovoltaic modules connected in series by a bus with a voltage detection circuit that provides an indicator of the bus voltage to each module, allowing independent control of output voltages using controllers, which can apply control routines like PI control to maintain the bus voltage within a desired range, and an inverter converts the combined DC input to AC output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a central controller is used to control multiple photovoltaic modules, then coordination and stability are improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the control function into independent segments, with each photovoltaic module having its own controller that operates autonomously. This segmentation eliminates the need for a complex central controller while maintaining system coordination through distributed decision-making based on local voltage detection and control routines.
Solution Approach 2:
Each photovoltaic module is equipped with its own controller that independently manages its output based on detected bus voltage conditions. The modules self-regulate their contribution to the bus without requiring external coordination, reducing overall system complexity while maintaining stability through decentralized control.
2Adaptability or versatility
If output voltage of photovoltaic modules is allowed to vary freely, then adaptability to changing conditions is improved, but difficulty in maintaining efficient conversion increases
Solution Approach 1:
The patent implements a feedback mechanism where each module's controller continuously monitors the bus voltage and adjusts its output accordingly. This feedback loop allows the system to adapt to changing conditions while maintaining efficient conversion, as each module responds to real-time voltage conditions to optimize its power contribution.
Solution Approach 2:
The control system dynamically adjusts the output voltage of each photovoltaic module based on real-time bus voltage conditions. This dynamic response allows the system to adapt to varying environmental conditions and load requirements while maintaining efficient power conversion through continuous optimization of module outputs.
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 allows for rapid and efficient control of output voltages, reducing the need for a central controller, lowering costs and complexity, and ensuring stable AC output by directly controlling each module's output in response to bus voltage changes, thereby maintaining efficient inverter operation.
Implementation Method 1
a voltage detection circuit to detect a bus voltage at an output of the bus
Implementation Method 2
Solar panels generate Direct Current (DC) voltages
Data Source
AI summary
An apparatus includes a plurality of photovoltaic modules including at least a first and a second photovoltaic module having outputs connected in series by a bus. A voltage detection circuit detects a bus voltage at an output of the bus, to provide an indicator of detected bus voltage to the first photovoltaic module, and to provide the indicator of detected bus voltage to the second photovoltaic module.