Photovoltaic Power Station Surplus Energy Management
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Solution Overview
Problem
Conventional photovoltaic (PV) power stations using blind maximum power point trackers (MPPT) devices often result in suboptimal electricity delivery to the grid due to inefficiencies in energy extraction and utilization, leading to surplus energy being wasted as heat rather than being utilized effectively.
Innovation Solution
The implementation of a Maximum Energy Utilization Point Tracker (MEUPT) optimizer, which includes a surplus energy extractor, an energy reservoir, and a MEUPT controller, allows for the temporary storage and synchronized delivery of surplus energy to the grid, enhancing electricity sales revenue by capturing and utilizing leftover energy that cannot be immediately converted for grid supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If blind MPPT devices are used to track maximum power production points, then the system can operate with simple control logic, but surplus energy is wasted as heat instead of being delivered to the grid
Solution Approach 1:
The PV power station is divided into multiple independent AC power production units, each with its own DC power generator and DC/AC converter. This segmentation allows each unit to independently manage and deliver surplus energy to the grid without affecting other units, thereby reducing overall energy waste while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
An energy reservoir is introduced as an intermediary component between the DC power generator and the DC/AC converter. The energy reservoir temporarily stores surplus DC energy that cannot be immediately converted to AC power for grid delivery. This mediator enables the system to capture and utilize surplus energy that would otherwise be wasted as heat, while the control system manages the energy flow based on grid conditions.
2Productivity
If the total declared power rating of DC/AC converters is limited to match solar string capacity, then the system maintains balanced power flow, but the power station cannot deliver more power to the grid even when surplus energy is available
Solution Approach 1:
The energy reservoir is pre-charged with surplus DC energy from the solar strings during periods when the grid cannot accept all available power. This preliminary energy storage allows the system to rapidly deliver accumulated energy to the grid when conditions permit, thereby increasing overall power delivery capability without requiring additional converter capacity beyond the original solar string rating.
Solution Approach 2:
The system dynamically changes the operating parameters of the DC/AC converters based on grid conditions and energy reservoir status. When the grid can accept more power, the converters operate at higher output levels by drawing from both direct solar generation and the stored energy in the reservoir, effectively increasing power delivery beyond the instantaneous converter rated capacity without requiring physical expansion of converter hardware.
3Loss of energy
If surplus energy is not stored and utilized, then the system operates with simpler energy management, but energy utilization efficiency is reduced and revenue generation is limited
Solution Approach 1:
The MEUPT controller implements a feedback mechanism that continuously monitors the energy reservoir level, solar generation output, and grid acceptance conditions. Based on this feedback, the controller dynamically adjusts the charging rate of the energy reservoir and the discharge rate to the DC/AC converters, optimizing energy utilization efficiency. This feedback-based control maximizes revenue generation by ensuring surplus energy is captured and delivered to the grid whenever possible, while maintaining manageable complexity through rule-based decision logic.
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 MEUPT optimizer significantly increases the amount of electricity delivered to the grid by converting previously wasted surplus energy into usable AC power, thereby improving energy utilization efficiency and revenue generation for PV power stations.
Implementation Method 1
Photovoltaic (PV) power stations generate electricity by converting solar energy to electricity
Implementation Method 2
The first DC/AC 3-phase converter(s) receive DC power provided by the DC power generator, convert the received DC power into AC power
Data Source
AI summary
A photovoltaic (PV) power station includes at least one AC power production unit. The AC power production unit includes an energy reservoir that is supplied with DC energy from a DC power generator, such as PV panels. The energy reservoir is used as a buffer to store energy, and improve the efficiency of the PV power station. Whether or not an energy reservoir is used, decoupler devices may be used to prevent power annihilation that can decrease the amount of power delivered by the power station to the grid. In system integration for a PV power station, it is found that the declared rating of DC/AC converter in power grid convention should not be taken as the power conversion capability.