Stationary Energy Storage Controller for Photovoltaic Campus Power
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Solution Overview
Problem
Photovoltaic energy systems face challenges in optimizing energy storage and power distribution due to variability in solar intensity, leading to inefficiencies and increased energy grid purchases, which can result in higher costs.
Innovation Solution
An energy storage system that includes a photovoltaic energy field, a stationary energy storage device, an energy converter, and a controller. The controller generates a cost function to minimize energy purchases from the grid by optimizing the discharge rate of the energy converter, ensuring that the energy storage system uses only solar energy for charging and prevents energy return to the grid, while predicting campus and photovoltaic loads to manage energy distribution effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the battery is charged and discharged throughout the day to power a building, then the amount of energy purchased from the energy grid is reduced, but the control complexity increases
Solution Approach 1:
The controller dynamically adjusts the discharge rate parameter of the battery based on varying electricity prices and energy consumption patterns throughout the day. By changing operational parameters (charge/discharge rates) in response to external conditions, the system reduces grid energy purchases while maintaining manageable control complexity through adaptive rather than static control strategies.
2Productivity
If the discharge rate of AC power is optimized to minimize cost function, then the economic efficiency is improved, but the system constraints and control difficulty increase
Solution Approach 1:
The controller pre-calculates and applies discharge rate adjustments before peak pricing periods or high-consumption events occur. By performing preliminary actions (charging the battery in advance during low-cost periods), the system achieves economic efficiency improvements while simplifying real-time control decisions, as the optimization groundwork is already completed.
Solution Approach 2:
The control system continuously monitors energy consumption, discharge rates, and cost function variables, then adjusts the battery discharge rate based on feedback from these measurements. This closed-loop feedback mechanism enables the system to meet economic efficiency goals while adapting to actual operating conditions, reducing the burden of rigid constraint management.
3Reliability
If the system restricts the campus from returning power to the energy grid, then the energy self-sufficiency is improved, but the flexibility in energy management is reduced
Solution Approach 1:
The system segments energy management into distinct functional zones: a mandatory self-sufficiency core that prevents grid power import during high-cost periods, and a flexible optimization layer that can adjust discharge rates and operational parameters. This segmentation allows the system to guarantee energy self-sufficiency while maintaining flexibility within acceptable operational boundaries.
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 solution optimizes energy storage and distribution, reducing the amount of energy purchased from the grid, thereby lowering costs and improving the economic efficiency of powering a campus by effectively managing energy usage and generation.
Implementation Method 1
Photovoltaic energy systems are used to convert solar energy into electricity using solar panels or other materials that exhibit the photovoltaic effect
Data Source
AI summary
An energy storage system includes a photovoltaic energy field, a stationary energy storage device, an energy converter, and a controller. The photovoltaic energy field converts solar energy into electrical energy and charges the stationary energy storage device with the electrical energy. The energy converter converts the electrical energy stored in the stationary energy storage device into AC power at a discharge rate and supplies a campus with the AC power at the discharge rate. The controller generates a cost function of the energy consumption of the campus across a time horizon which relates a cost to operate the campus to the discharge rate of the AC power supplied by the stationary energy storage device. The controller applies constraints to the cost function, determines a minimizing solution to the cost function which satisfies the constraints, and controls the energy converter.