Method for controlling battery charging/discharging current in off-grid mode of hybrid energy storage inverter
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Solution Overview
Problem
The challenge of preventing lithium battery overcharging in an off-grid mode of a hybrid energy storage inverter due to excess photovoltaic energy when the battery is fully charged.
Innovation Solution
A method for controlling battery charging and discharging current in the off-grid mode, involving setting bus voltage reference values and implementing control loops to manage the flow of energy between photovoltaic and battery sources, ensuring safe operation by preventing overcharging and maintaining stable power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If excess photovoltaic energy is continuously stored in the battery when the battery is fully charged, then energy storage capacity is improved, but battery overvoltage or damage occurs
Solution Approach 1:
The patent implements a control method that continuously monitors the battery charging state and provides feedback signals to adjust the charging current. When the battery reaches full charge, the system detects this state and automatically adjusts or stops the charging process, preventing overvoltage and damage while maximizing energy storage capacity
Solution Approach 2:
The control system dynamically adjusts the battery charging current based on real-time battery state of charge. The charging current is not fixed but varies according to battery needs, being higher when the battery can accept charge and reduced or stopped when fully charged, thus preventing overcharging while optimizing energy storage
2Productivity
If photovoltaic energy is prioritized for battery storage, then energy utilization is improved, but stable power supply to load may be compromised
Solution Approach 1:
The patent segments the photovoltaic energy into two separate pathways: one for immediate load supply and another for battery storage. The control system divides the total photovoltaic output based on load requirements and battery charging needs, ensuring that load power supply stability is maintained while maximizing energy utilization through coordinated management of both pathways
Data Source
AI summary
Disclosed is a method for controlling battery charging/discharging current in an off-grid mode of a hybrid energy storage inverter that is based on photovoltaic and a lithium battery. If photovoltaic energy is sufficient and a battery is not fully charged, the photovoltaic energy is supplied to a load and excess energy is supplied to the battery, to achieve maximum power point tracking of an output power of a photovoltaic component achieves maximum power point tracking; if photovoltaic energy is sufficient and a battery has been fully charged, the photovoltaic energy is supplied to a load, the excess photovoltaic energy is prohibited from charging the battery to prevent overcharging of the lithium battery; if photovoltaic energy is insufficient, the photovoltaic energy and battery energy are jointly supplied to a load, to achieve maximum power point tracking of an output power of a photovoltaic component.