Seven-Switch Indirect Matrix Converter for Low-Loss EV Fast Charging
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Solution Overview
Problem
Current electric vehicle (EV) charging technologies are inefficient and take longer to recharge batteries compared to refueling internal combustion engine vehicles, necessitating faster and more efficient charging solutions.
Innovation Solution
A DC fast charger with a seven-bidirectional-switch topology and a control system that transforms low-frequency AC power into high-frequency AC power using an indirect matrix converter, reducing power loss and enabling bidirectional current flow while controlling the power factor, thereby improving charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional six-switch topology is used, then device complexity is reduced, but power loss increases and charging efficiency decreases
Solution Approach 1:
The patent divides the charging system into two independent circuits: a primary circuit with seven bidirectional switches connected to the power grid, and a secondary circuit with six switches connected to the battery. This segmentation allows each circuit to be optimized independently, reducing overall power loss while maintaining manageable complexity in each section.
Solution Approach 2:
The patent implements dynamic switching between different circuit configurations by introducing a seventh bidirectional switch in the primary circuit that can operate in conjunction with the traditional six switches. This dynamic reconfiguration enables the system to adapt to different operating conditions, optimizing power flow and reducing losses without permanently increasing device complexity.
2Loss of time
If faster charging is implemented, then charging time is reduced, but power loss increases
Solution Approach 1:
The patent changes the operational parameters of the switching circuits by implementing seven bidirectional switches in the primary circuit instead of the conventional six. This parameter change enables more flexible control of power flow, allowing the system to deliver higher charging speeds while maintaining lower power loss through optimized switching sequences and reduced conduction losses.
Solution Approach 2:
The system dynamically adjusts switching frequencies and duty cycles based on real-time operating conditions. The control system monitors power flow and automatically optimizes switching parameters to achieve fast charging while minimizing power losses, allowing the system to adapt to varying load conditions and battery states.
3Adaptability or versatility
If bidirectional power flow is enabled, then versatility is improved, but device complexity increases
Solution Approach 1:
The seventh bidirectional switch in the primary circuit serves multiple functions: it enables bidirectional power flow for vehicle-to-grid (V2G) operations, provides additional control flexibility for power factor correction, and can operate in conjunction with the other switches for enhanced power distribution. This single component adds versatility without proportionally increasing overall system complexity.
4Productivity
If seven-bidirectional-switch topology is used, then charging efficiency is improved, but device complexity increases
Solution Approach 1:
The patent segments the switching functions between two independent circuits: the primary circuit handles grid connection and power factor correction with seven bidirectional switches, while the secondary circuit handles battery connection with six switches. This segmentation distributes the complexity across manageable sections while achieving overall improved charging efficiency through optimized power flow control.
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 solution decreases power loss and conduction loss by half compared to conventional six-switch topologies, allowing for faster and more efficient charging of EV batteries while enabling bidirectional power flow and reduced complexity.
Implementation Method 1
a primary circuit, having seven bidirectional switches, electrically linked to a primary wire of a transformer (with or without an external inductor) and configured to receive alternating current (AC) power from a power grid
Data Source
AI summary
A direct current (DC) fast charger for charging batteries of electric vehicles (EVs), includes a primary circuit, including seven bidirectional switches, electrically linked to a primary wire of a transformer and configured to receive alternating current (AC) power from a power grid; a secondary circuit electrically linked to a secondary wire of the transformer for converting AC power into DC power; and a control system, electrically linked to the primary circuit and the secondary circuit, that changes the frequency of the AC power received from the power grid in five switching states.