Integrated PV-Battery Converter for Solar Intermittency Smoothing
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Solution Overview
Problem
Photovoltaic power plants face intermittency issues due to weather variations, leading to unstable active power injection into the electrical grid and underutilization of converters designed for peak power capacity.
Innovation Solution
A control system and method that connects a secondary converter, battery bank, photovoltaic array, and instrumentation system to mitigate intermittency by using a four-layer cascaded control system, allowing the power electronic converter to operate with reduced power and avoiding converter underutilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an energy storage system is connected to the AC bus independently of the photovoltaic arrays, then generation smoothing can be achieved, but the converter capacity must be designed for peak power resulting in underutilization
Solution Approach 1:
The patent combines the energy storage system converter with the photovoltaic converter into a single integrated converter. This merging allows the converter to handle both photovoltaic power conversion and energy storage power conversion, fully utilizing the converter capacity for peak power handling while providing generation smoothing through coordinated control of both power sources.
Solution Approach 2:
The integrated converter is designed to perform multiple functions: converting photovoltaic DC power to AC grid power, charging the energy storage system, discharging the energy storage system, and providing grid support functions. This multi-functionality ensures the converter operates at optimal utilization levels while achieving generation smoothing.
2Power
If converter capacity is designed for peak power, then peak power handling capability is ensured, but the converter operates with reduced capacity during normal operation causing underutilization
Solution Approach 1:
The patent implements dynamic capacity allocation where the converter's power handling is dynamically adjusted based on real-time operating conditions. The control system continuously optimizes the distribution of converter capacity between photovoltaic conversion, energy storage charging/discharging, and grid support functions, ensuring high utilization without sacrificing peak power capability.
3Device complexity
If photovoltaic power plant operates without integrated energy storage, then system complexity is reduced, but generation intermittency causes grid instability
Solution Approach 1:
The patent integrates the energy storage system with the photovoltaic power plant through a unified converter and control system. This integration achieves generation smoothing and grid stability while minimizing additional complexity by sharing common components (converter, control infrastructure, monitoring systems) between the photovoltaic and energy storage functions.
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 smooths power fluctuations, reducing grid instability and preventing converter underutilization by optimizing power injection and storage system efficiency.
Implementation Method 1
battery bank (2), photovoltaic array (3), primary converter (4) and instrumentation system (5)
Implementation Method 2
secondary converter (1), battery bank (2), photovoltaic array (3), primary converter (4)
Implementation Method 3
photovoltaic array (3), primary converter (4)
Data Source
AI summary
The present invention provides a system and method for smoothing photovoltaic power generation. Photovoltaic power plants have the inherent problem of generation intermittency caused by the variation in weather conditions over a period of seconds, minutes, and hours. This intermittency results in a variability of active power injection into the electrical grid by the photovoltaic power plant.