Onboard Power Converter Switching for Weak-Grid Vehicle Charging
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Solution Overview
Problem
Existing vehicles, particularly watercraft, face challenges in efficiently charging onboard energy storage units due to limited power availability at land-based charging stations, leading to inefficient and costly energy conversion processes.
Innovation Solution
An onboard power subsystem with a power converter that operates as both a DC/DC converter during charging and an AC/DC converter during independent operation, utilizing a closed-loop control device to optimize energy transfer and reduce conversion losses, allowing for flexible charging at various voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If AC-DC voltage conversion is used for charging, then compatibility with land-based charging stations is achieved, but energy losses increase and charging efficiency decreases
Solution Approach 1:
The patent changes the voltage conversion parameter from AC-DC to DC-DC conversion. The power converter is configured to perform DC-DC conversion when connected to a DC voltage source, eliminating the inefficient AC-DC conversion step and reducing energy losses during voltage transformation.
Solution Approach 2:
The power converter is designed with multi-functionality to operate in different modes: it can perform AC-DC conversion when connected to AC voltage sources and DC-DC conversion when connected to DC voltage sources. This universal capability allows the system to adapt to different charging station types while optimizing for DC-DC efficiency.
2Adaptability or versatility
If a power converter operating as AC/DC converter is used, then flexibility in power source compatibility is achieved, but device complexity increases
Solution Approach 1:
The power converter is designed as a universal device capable of both AC-DC and DC-DC conversion functions. This multi-functionality is achieved through a unified converter architecture that can operate in different modes based on the input power source type, reducing the need for separate dedicated converters.
Solution Approach 2:
The converter configuration is made dynamic and adaptable through closed-loop control that automatically detects the input power source type and adjusts the conversion mode accordingly. This dynamic adaptation simplifies the overall system design by eliminating the need for manual configuration or multiple static converter designs.
3Productivity
If DC voltage connection is implemented for land-based charging, then charging efficiency improves, but compatibility with weak grids decreases
Solution Approach 1:
The system changes the voltage conversion approach from AC-DC to DC-DC when connected to DC voltage sources, which improves charging efficiency by eliminating redundant conversion steps. This parameter change optimizes the charging process while maintaining adaptability through the power converter's dual-mode capability.
Solution Approach 2:
The power converter maintains universality by supporting both AC-DC and DC-DC conversion modes, allowing the system to connect to different grid types including weak grids. When connected to DC voltage sources from weak grids, the system uses DC-DC conversion to maintain efficiency while adapting to the available power source.
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
Enhances charging efficiency by minimizing conversion losses and reducing the need for high-power components, enabling cost-effective and reliable energy storage unit charging across different voltage levels.
Implementation Method 1
a power converter that is connected on the AC voltage side to the energy subsystem and can be operated both as an AC/DC converter and as a DC/DC converter
Data Source
AI summary
An on-board power subsystem has an energy storage unit and a control device for charging the energy storage unit, as well as an on-board power connection for connection to electrical components of the vehicle, and a DC voltage connection for connection to a land-based charging station and an energy subsystem. A switching device is arranged between the on-board power connection and the energy subsystem, and a charger is arranged between the energy storage unit and the energy subsystem. The on-board power subsystem has at least one power converter connected on the AC voltage side to the energy subsystem and operable both as an AC/DC converter and as a DC/DC converter. The control device can operate the energy subsystem as a DC voltage grid during the charging process and as an AC voltage grid during independent operation of the vehicle.