Flywheel EV Charging With Line-Start Synchronous Storage
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Solution Overview
Problem
High-power electric vehicle charging stations strain the grid and require costly and complex installations, and existing energy storage solutions like electrochemical batteries and flywheel systems are complex and costly due to AC/DC conversion requirements.
Innovation Solution
A flywheel energy storage system using a line-start synchronous motor that can operate across a range of speeds, eliminating the need for power electronics and allowing direct AC/DC conversion, storing energy from the grid and supplementing it during high-power charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power DCFC chargers are installed to meet increasing EV charging demand, then charging power capability is improved, but grid strain and installation cost increase
Solution Approach 1:
The charging system is segmented into two independent power sources: the grid connection and the flywheel energy storage system. The flywheel module can be independently installed and operated, allowing the charging station to achieve high power capability without requiring the entire system to be upgraded at once. This modular approach reduces installation complexity while maintaining high charging power capability.
2Quantity of substance
If electrochemical battery systems are used for energy storage, then power accumulation capability is improved, but system complexity increases due to AC/DC conversion requirements
Solution Approach 1:
The patent extracts and eliminates the complex AC/DC conversion power electronics from the energy storage system. By using a flywheel with a direct-drive synchronous generator, the system directly outputs AC power that can be fed back to the grid or used for charging, bypassing the need for rectifiers, inverters, and associated control systems required by electrochemical battery systems.
Solution Approach 2:
The patent replaces the electrochemical energy storage mechanism with a mechanical flywheel energy storage system. The flywheel stores energy kinetically through rotation, and the synchronous generator converts this mechanical energy directly to electrical energy without requiring complex power electronic conversions, thereby simplifying the overall system architecture.
3Quantity of substance
If conventional flywheel systems are used, then energy storage capability is improved, but system complexity increases due to variable speed AC/DC/AC conversion requirements
Solution Approach 1:
The synchronous generator serves multiple functions simultaneously: it acts as both the energy conversion device from mechanical to electrical energy and as a direct AC power source compatible with grid frequency. This multi-functionality eliminates the need for separate AC/DC and DC/AC conversion stages, reducing power electronics complexity while maintaining energy storage capability.
4Productivity
If grid power is drawn during peak times to meet high charging demand, then charging availability is improved, but grid strain and electricity cost increase
Solution Approach 1:
The flywheel energy storage system accumulates energy in advance by drawing power from the grid during off-peak hours when electricity rates are lower and grid demand is reduced. This pre-charged energy is then available for immediate discharge during peak charging demand periods, ensuring charging availability while avoiding high peak-time electricity costs and reducing grid strain.
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
Reduces grid strain by limiting power draw during peak times, stabilizes the grid, and simplifies installation by eliminating the need for complex power electronics, enabling efficient and cost-effective high-power charging.
Implementation Method 1
a flywheel energy storage system using a line-start synchronous motor that can operate across a range of speeds, eliminating the need for power electronics and allowing direct AC/DC conversion
Implementation Method 2
storing energy from the grid and supplementing it during high-power charging
Implementation Method 3
A flywheel energy storage system using a line-start synchronous motor that can operate across a range of speeds
Data Source
AI summary
A system for storing input power and providing output power, such as for use with electric vehicle charging, can include an alternating current motor, a flywheel, an alternating current generator, or any combination thereof. The motor can be electrically coupled to an alternating current power source and can receive AC power from the power source. The flywheel can be coupled to a rotor external to the motor. The generator can be coupled to the flywheel and electrically coupled to a controller for supplying power to a load, such as an electric vehicle for charging one or more batteries of the vehicle.