Split-Phase Onboard Charger for Bidirectional V2X Power

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Solution Overview

Problem

Existing onboard charging architectures for electric vehicles are limited in their ability to efficiently manage bidirectional power flow, particularly in providing split-phase voltage outputs while maintaining single-phase capabilities, which is essential for vehicle-to-anything (V2X) operations.

Innovation Solution

A split-phase onboard charging module architecture that incorporates two DC-AC converters and a DC-DC converter, along with a switchgear block, to enable selective output of split-phase or single-phase voltage, allowing for enhanced power management during charging and discharging modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single-phase bidirectional OBC architecture is used, then the device complexity is reduced, but the adaptability for split-phase voltage output is insufficient

Engineering Contradiction:

Improvesplit-phase voltage output capabilityVSAvoidconverter architecture complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The OBC is divided into two separate DC-AC converter modules (first and second converters) that can independently generate AC voltage waveforms. Each converter handles one phase, allowing the system to output either single-phase or split-phase voltage by controlling which converters are active and how their outputs are combined through the switchgear block.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dual-converter architecture enables the OBC to perform multiple functions: it can output single-phase voltage by using one converter, split-phase voltage by using both converters with 180° phase shift, and bidirectional power flow for both charging and discharging modes. The switchgear block provides universal connectivity for different output configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Power

If two DC-AC converters are used for split-phase output, then the power capability is improved, but the device complexity increases

Engineering Contradiction:

Improvetotal charging power capabilityVSAvoidconverter and switchgear architecture

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The first and second DC-AC converters are merged into a single integrated OBC system with shared control electronics and a common DC link. The switchgear block combines the outputs of both converters, allowing the system to achieve higher total power capability by operating both converters simultaneously in split-phase mode while maintaining a unified device structure.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If diode rectification is used in existing OBC, then the manufacturing simplicity is maintained, but the bidirectional power flow capability is limited

Engineering Contradiction:

Improvebidirectional power flow capabilityVSAvoidpower conversion process complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of using diode rectification that allows only unidirectional power flow (grid to vehicle), the patent employs bidirectional DC-AC converters that can operate in reverse mode. The same converter circuitry that converts DC to AC for vehicle-to-load operation can also convert AC to DC for charging, eliminating the need for separate rectification circuits and enabling true bidirectional power flow.

Inventive Principle:

Principle #13The other way round (Inversion)

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

This solution enables efficient power conversion and distribution, reducing mass and packaging requirements, while facilitating vehicle-to-grid (V2G) and vehicle-to-load (V2L) operations by providing a split-phase AC voltage output, thereby enhancing the overall performance and flexibility of electric vehicle charging systems.

Implementation Method 1

the first and second DC-AC converters are configured to output a DC link voltage to the DC-DC converter... the first and second DC-AC converters are configured to receive a DC discharging voltage or current from the DC-DC converter and together selectively output a split-phase AC voltage

Methodology Applied

Scientific EffectElectrical Energy Transformation:

Data Source

PatentUS11863004B2Split-phase bidirectional on-board charger

Publication Date: 2024.01.02 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A split-phase bidirectional on-board charger (OBC) has separate charging and discharging modes, and includes a switchgear block connectable to an offboard charging station during the charging mode, and to an external alternating current (AC) load during the discharging mode. The OBC includes first and second DC-AC converters connected to the switchgear block and DC-DC converter connected to the first and second DC-AC converters and a DC bus. During the charging mode, the DC-AC converters output a DC link voltage to the DC-DC converter. The DC-DC converter outputs a DC charging voltage or current to the DC bus when the link voltage reaches a predetermined value. During the discharging mode, the DC-AC converters receive a DC discharging voltage or current from the DC-DC converter and together selectively output a split-phase AC voltage through the switchgear block to the AC electrical load.