V2X DC Bus Pre-Charging for Cable Isolation Verification
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Solution Overview
Problem
Current vehicle-to-load (V2X) charging devices lack a high voltage energy source prior to closing the donor vehicle's disconnect device, making it difficult to verify isolation of the high voltage cable and pre-charge the DC-DC converter's input during V2X charging events.
Innovation Solution
Incorporating a DC bus charge module with a DC boost converter that applies a first voltage level to the DC bus cable and charges an electrical charge storage device with a second voltage level, allowing for cable insulation verification and pre-charging of the DC-DC converter without being connected to the high voltage DC source, using a suitable DC boost converter to convert an auxiliary low voltage to a higher output voltage for verification and charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a V2X charging device is used without a high voltage energy source prior to closing the disconnect device, then the device complexity is reduced, but the ability to verify cable insulation and pre-charge the DC-DC converter cannot be achieved
Solution Approach 1:
The patent applies preliminary action by pre-charging the DC-DC converter and verifying cable insulation before closing the disconnect device. The system performs these safety checks in advance using the auxiliary battery and control circuitry, ensuring that the high voltage cable is properly isolated and the converter is ready to receive power before the main disconnect device closes, thus resolving the contradiction between simplified device structure and reliable safety verification
Solution Approach 2:
The patent uses an auxiliary battery as an intermediary energy source to enable cable insulation verification and DC-DC converter pre-charging without requiring the main high voltage source to be connected. This intermediary power source allows the system to perform necessary safety checks and initialization procedures independently, resolving the contradiction by providing the needed functionality through a separate, controlled power path
2Reliability
If the DC bus cable is disconnected from the DC voltage source during pre-charging, then safety is improved, but the ability to charge the electrical charge storage device is compromised
Solution Approach 1:
The patent segments the power system into separate power paths: the main high voltage source path and the auxiliary pre-charging path. By disconnecting the DC bus cable from the main voltage source during pre-charging operations and using a separate auxiliary battery through controlled switches, the system maintains safety isolation while enabling charge storage device pre-charging through the auxiliary path, thus resolving the contradiction between safety isolation and charging capability
Solution Approach 2:
The auxiliary battery serves as an intermediary power source that enables charge storage device pre-charging without requiring connection to the main high voltage DC source. This intermediary approach allows the system to maintain safety isolation (disconnected main source) while still providing the energy needed for pre-charging operations through the auxiliary power path
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
Enables safe and efficient initialization of V2X charging sessions by verifying cable insulation and pre-charging the DC-DC converter, ensuring safe energy transfer and reducing the need for additional communication hardware, facilitating charging of vehicles or other loads without extra hardware.
Implementation Method 1
a DC boost converter configured to: apply an output DC voltage from the DC boost converter and having a first voltage level to a DC bus cable with the DC bus cable disconnected from a first DC voltage source; and charge an electrical charge storage device that is electrically connectable to the DC bus cable with an output DC voltage from the DC boost converter and having a second voltage level that is different from the first voltage level
Data Source
AI summary
Various disclosed embodiments include illustrative DC bus charge modules, V2X charging devices, and methods for pre-charging a V2X charging device. An illustrative direct current (DC) bus charge module includes a DC boost converter configured to: apply an output DC voltage from the DC boost converter and having a first voltage level to a DC bus cable with the DC bus cable disconnected from a first DC voltage source; and charge an electrical charge storage device that is electrically connectable to the DC bus cable with an output DC voltage from the DC boost converter and having a second voltage level that is different from the first voltage level with the DC bus cable disconnected from the first DC voltage source.