Bidirectional OBC Architecture & V2G — PatSnap Eureka
Bidirectional OBC Architecture: How It Enables V2G in Next-Gen EVs
Bidirectional on-board chargers replace legacy diode rectification with fully controllable switch-mode topologies — unlocking V2G, V2L, V2H, and V2V from a single on-board converter. Explore the 40+ patent innovations shaping this space with PatSnap Eureka.
Replacing Diode Rectification: The Core Enabler of V2G
The fundamental enabler of V2G is the replacement of one-way diode rectification in legacy OBCs with fully controllable semiconductor switches in both the AC/DC and DC/DC conversion stages. As documented in GM Global Technology Operations LLC's split-phase bidirectional OBC patent (2023), conventional OBC architectures tend toward diode rectification, making power conversion inherently unidirectional. Emerging bidirectional OBC architectures allow selective power flow in the reverse direction, enabling the battery to supply the grid (V2G) or external connected loads (V2L).
GM's split-phase design employs two DC-AC converters connected to a switchgear block and a DC-DC converter linked to a DC bus. In charging mode, the DC-AC converters output a DC link voltage to the DC-DC converter; in discharging mode, the DC-AC converters receive a DC discharging voltage from the DC-DC converter and together selectively output a split-phase AC voltage to the external electrical load — a key architectural distinction tracked by PatSnap's IP analytics platform.
For applications requiring simultaneous management of both high-voltage (HV) and low-voltage (LV) batteries, the WIPO-registered University of Maryland PCT filing and its US grant propose a compact three-port power electronic system built on triple-active-bridge (TAB)-derived topologies. These modular implementations support bidirectional power transfer among all three ports — the grid, the HV battery, and the LV battery — with minimized reactive power, active circulating current reduction, and ensured soft-switching for MOSFET devices. The approach directly supports V2G by enabling the HV battery to push power back through the grid port without dedicated additional hardware.
A multi-function topology using a front-stage Sepic-Zeta bridgeless PFC combined with a bidirectional CLLLC resonant converter from Xi'an University of Technology (2023) simultaneously provides G2V, V2G, V2V, and V2L functions with an output voltage range adjustable from 250 V to 750 V — achieved through a forward/reverse symmetrical resonant stage that facilitates soft-switching in both power-flow directions.
Key Assignees & V2X Mode Coverage Across the Dataset
Derived from analysis of 40+ patents across Korean, US, Chinese, European, and international jurisdictions via PatSnap Eureka.
Bidirectional OBC Patent Filings by Assignee
GM Global Technology Operations leads hardware-level bidirectional OBC filings; Korean academic institutions dominate integrated topology research.
V2X Mode Coverage by Bidirectional OBC Architectures
V2G is universally supported; wireless V2X represents the frontier, addressed by China EPRI's dynamic wireless push system.
OBC-LDC Integration and V2G Relay Protection Mechanisms
Next-generation EV power systems integrate the OBC with the LDC to increase power density and reduce component count while preserving full bidirectional V2G capability.
DAB OBC + PSFB LDC: Shared Magnetics for V2G
Inha University's bidirectional EV charger integrates a DAB (Dual-Active Bridge) OBC and a PSFB (Phase-Shift Full-Bridge) LDC through shared secondary and primary sides via a combination of switches, diodes, and an external inductor. The OBC and LDC transformers are further integrated through a shared leakage inductance and magnetizing inductance. The device operates in a charging mode (simultaneously charging both HV and LV batteries) and a discharging mode — directly supporting V2G by enabling simultaneous discharge to the grid while maintaining the LV auxiliary bus. Learn more about PatSnap's EV power electronics intelligence.
Shared magnetics · Simultaneous HV+LV dischargeOBC + LDC + Traction Converter: Single Unified Topology
Yonsei University's Integrated Power Conversion System extends the OBC-LDC concept further by integrating the OBC, LDC, and traction converter into a single circuit, explicitly implementing G2V, V2G, and traction/LDC modes within one unified power conversion topology. The multi-functional multi-ratio OBC/LDC integrated circuit (Yonsei, 2021) enables bidirectional G2V and V2G over a wide voltage range without additional control overhead by selectively switching transformer turns ratios, while operating with only a small number of active switches during LDC function to maximize charging efficiency.
Traction integration · Turns-ratio switchingDual-Relay V2G Protection: Fast Deterministic Shut-Off
Hyundai Motor Company's OBC patent details a vehicle port connected to an external charger containing a first relay on an internal power supply path and a second relay on the path between the vehicle port and the power converter. The controller turns off both relays when a V2G protection operation is determined necessary based on power-related parameters — providing a fast, deterministic hardware response to abnormal grid conditions. The 2026 US grant confirms this protection triggers a V2G protection operation as a function of power-related parameter monitoring, enabling rapid disconnection before damage propagates. This aligns with IEEE grid interconnection safety standards.
Dual relay · Power-parameter triggered shut-offMulti-Source OBC Control: Indoor Outlets + V2G Simultaneously
Multi-source OBC control — where the bidirectional OBC must simultaneously manage power from multiple AC phases for both indoor outlet loads and V2G export — is addressed in Hyundai's 2023 patent. The apparatus branches a line supplying the indoor power outlet from a line other than the single-phase AC charging line among three-phase AC inputs, measures the required current of connected electronics, and controls the bidirectional OBC based on that current measurement. The 2025 extension further synchronizes a low-frequency leg within the bidirectional OBC to either AC port based on measured phase angles.
3-phase AC management · Phase-angle synchronizationBeyond V2G: The Full Spectrum of Bidirectional OBC Applications
Bidirectional OBC architecture underpins a spectrum of power delivery modes — from emergency home backup to dynamic wireless energy dispatch on moving vehicles.
V2L: Power External Loads While Driving or Parked
Shenzhen Xin-Rui Technology's 2021 bidirectional OBC includes two independent AC discharge interfaces and a DC interface, capable of supplying external loads (V2L) during both driving and parked states through switching circuit control — resolving the specific technical problem of providing energy to external loads while the vehicle is in motion. This is tracked by PatSnap customers in the EV sector.
V2H: Emergency Home Power During Natural Disasters
The same Shenzhen Xin-Rui assignee's 2021 patent articulates how bidirectional OBCs regulate grid peak-valley differentials, enable V2H emergency power during natural disasters, and function as V2L for recreational power needs — establishing the home-backup use case as a primary design driver alongside V2G grid arbitrage.
V2V: Dedicated Buck-Boost HV-to-HV Charging Unit
GM's 2026 Chinese patent on vehicle-to-vehicle charging uses a dedicated bidirectional buck-boost HV-to-HV converter and a bidirectional HV-to-LV converter within a standalone charging unit. During V2V operation, a supply equipment communication controller (SECC) detects the charge port control signal, closes donor and recipient HV circuit breakers, and DC charging current is selectively discharged from the donor battery through the HV-to-HV converter to the recipient battery.
Wireless V2X: Dynamic Bidirectional Energy Push Without a Plug
China Electric Power Research Institute's 2019 (updated 2024) patent describes a monitoring system that collects energy and position information from both roadside transmitters and vehicle-mounted receivers, determines the energy interaction mode based on energy status of each node, and issues control commands so that either the roadside unit replenishes the vehicle or the vehicle energy receiver replenishes the roadside unit — solving the energy interaction problem between the IEA-tracked grid and EVs without requiring a physical plug.
Key Players Shaping Bidirectional OBC & V2G Innovation
GM Global Technology Operations LLC is the most prolific filer in the hardware-level bidirectional OBC space within this dataset, with multiple US, CN, and DE patents covering the split-phase bidirectional OBC (2024), the V2LIM-based OBC (2025), V2V charging units, pre-optimization of V2G discharge events (2024), and vehicle grid integration (VGI) control logic (2023). Track GM's full bidirectional OBC portfolio on PatSnap Eureka.
Hyundai Motor Company concentrates its filings on bidirectional OBC control for multi-source AC environments and V2G relay protection, appearing in both Korean and US jurisdictions with patents on indoor/outdoor outlet management, multi-phase synchronization, and fast relay shut-off during abnormal V2G conditions.
University of Maryland (US, WO) and Korean academic institutions — Inha University, Yonsei University, Chonnam National University — dominate the integrated power topology research, pushing TAB, DAB, PSFB, and reconfigurable OBC/LDC/traction-converter architectures that simultaneously reduce component count and enable bidirectional operation. This academic innovation is tracked through PatSnap's IP analytics platform.
Eaton Intelligent Power Limited (US, CA) leads in bidirectional EVSE infrastructure design, particularly in grid-side communication, aggregator interfacing, smart circuit protection, and backup control power for islanding scenarios. Their EVSE includes a voltage sensor for both grid and EV voltage, a smart circuit breaker that disables PWM signals before opening contactors, a backup control power supply that sustains EVSE control when the grid is unavailable, and a bidirectional communications controller that interfaces with the EV, load center, and grid aggregator across mode transitions.
China Electric Power Research Institute and Southern Grid Research Institute lead in system-level modeling of V2G and V2V coexistence scenarios and dynamic wireless V2X bidirectional push systems. An important regulatory and software-layer trend is represented by Siemens (EP) and Korea Electric Power Corporation (KR), which address the OBC-to-grid communication interface — firmware upgrades for V2G, integrated module communication with P2M operating systems for bidirectional scheduling, and V2G-V2B linked power management. These trends are aligned with U.S. Department of Energy grid modernization priorities.
What the Patent Dataset Tells Us About V2G Enablement
Six core findings drawn from 40+ patents across five jurisdictions, traceable to specific assignees and filings.
| Technical Finding | Key Assignee | Mechanism |
|---|---|---|
| Diode replacement enables reverse flow | GM Global Technology Operations (2023) | Dual DC-AC converters + DC-DC converter selectively output split-phase AC during discharge |
| TAB topology: 3-port simultaneous interaction | University of Maryland (2021) | Soft-switched multi-port bidirectional power transfer with minimized reactive power; no additional hardware needed for V2G |
| OBC-LDC integration increases power density | Inha University (2025) | DAB OBC and PSFB LDC share magnetics and switches; simultaneous discharge to grid while maintaining LV bus |
| Relay coordination is a critical V2G safety mechanism | Hyundai Motor Company (2026) | Dual-relay turn-off logic triggered by power-related parameter monitoring; protects vehicle and grid during abnormal V2G events |
| Bidirectional EVSE operationalizes on-board V2G | Eaton Intelligent Power (2025) | Smart circuit breaker disables PWM before opening contactors; backup control power sustains EVSE when grid unavailable |
| Firmware upgrades reduce V2G capital barrier | Siemens Industry (2024) | V2G-compatible firmware loaded onto existing V1G charger; cloud-based authorization establishes V2G communication interface without hardware replacement |
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Bidirectional OBC & V2G — key questions answered
Conventional OBC architectures tend toward diode rectification, making power conversion inherently unidirectional. Emerging bidirectional OBC architectures replace diode rectification with fully controllable semiconductor switches in both the AC/DC and DC/DC conversion stages, allowing selective power flow in the reverse direction — enabling the battery to supply the grid (V2G) or external connected loads (V2L).
The University of Maryland's TAB-derived topology is a compact three-port power electronic system that supports bidirectional power transfer among all three ports — the grid, the HV battery, and the LV battery — with minimized reactive power and active circulating current and ensured soft-switching for MOSFET devices. This directly supports V2G by enabling the HV battery to push power back through the grid port without dedicated additional hardware.
Integrating the OBC with the LDC (Low-Voltage DC/DC Converter) increases power density and reduces component count while preserving full bidirectional capability. Inha University's architecture integrates a DAB OBC and a PSFB LDC through shared magnetics and switches to support simultaneous discharge to the grid while maintaining the LV auxiliary bus.
Hyundai Motor Company's OBC patent details a vehicle port connected to an external charger containing a first relay on an internal power supply path and a second relay on the path between the vehicle port and the power converter. The controller turns off both relays when a V2G protection operation is determined necessary based on power-related parameters — providing a fast, deterministic hardware response to abnormal grid conditions.
Yes. Siemens Industry's 2024 European patent describes a method that loads V2G-compatible firmware onto an existing V1G charger and requires cloud-based authorization and local configuration — establishing a V2G communication interface for bidirectional charging and discharging without hardware replacement.
Bidirectional OBC architectures support a spectrum of power delivery modes including V2G (vehicle-to-grid), V2L (vehicle-to-load), V2H (vehicle-to-home for emergency power during natural disasters), V2V (vehicle-to-vehicle), and wireless dynamic V2X bidirectional energy exchange between roadside transmitters and vehicle-mounted receivers.
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References
- Split-phase bidirectional on-board charger — GM Global Technology Operations LLC, 2023
- Split-phase bidirectional on-board charger — GM Global Technology Operations LLC, 2024
- Vehicle to load inverter module based onboard charger — GM Global Technology Operations LLC, 2025
- 基于车辆到负载逆变器模块的车载充电器 — GM Global Technology Operations LLC, 2025
- Vehicle on-board charger for bi-directional charging of low/high voltage batteries — University of Maryland, 2021
- Vehicle on-board charger for BI-directional charging of low/high voltage batteries — University of Maryland College Park, 2019 (PCT)
- Bidirectional EV Charger Integrating OBC With LDC — Inha University, 2025
- Integrated Power Conversion System for Electric Vehicle — Yonsei University, 2022
- Multi-Functional Multi-Ratio OBC/LDC Integrated circuit — Yonsei University, 2021
- Integrated battery charging device for electric vehicles — Chonnam National University, 2025
- OBC for electric vehicle, relay control method thereof, and bidirectional charging system — Hyundai Motor Company, 2025
- On-board charger for electric vehicle, relay control method thereof, and bidirectional charging system — Hyundai Motor Company, 2026
- Apparatus for controlling bi-directional on board charger of electric vehicle and method thereof — Hyundai Motor Company, 2023
- On board charger control method and apparatus for multiple power supplies — Hyundai Motor Company, 2025
- Apparatus, system and method of AC and DC V2X and smart charging using a bidirectional EVSE — Eaton Intelligent Power Limited, 2025 (US)
- Apparatus, system and method of AC and DC V2X and smart charging using a bidirectional EVSE — Eaton Intelligent Power Limited, 2025 (CA)
- Upgrading an existing standard EV charger from V1G to V2G operation — Siemens Industry, Inc., 2024 (EP)
- 电动汽车V2X动态无线能量双向推送系统及方法 — China Electric Power Research Institute, 2019
- 电动汽车V2X动态无线能量双向推送系统及方法 — China Electric Power Research Institute, 2024
- 交通工具到交通工具充电单元和过程 — GM Global Technology Operations LLC, 2026
- 多功能双向隔离型的车载充电机及其控制方法 — Xi'an University of Technology, 2023
- 一种双向车载充电机和电动汽车 — Shenzhen Xin-Rui Technology, 2021
- 一种双向车载充电机、放电方法和电动汽车 — Shenzhen Xin-Rui Technology, 2021
- 用于在途电动车辆的策略机会充电 — Inverted Energy Ltd.
- WIPO — World Intellectual Property Organization (PCT filing authority)
- IEA — International Energy Agency: Global EV Outlook
- IEEE — Institute of Electrical and Electronics Engineers: Grid Interconnection Standards
- U.S. Department of Energy — Grid Modernization & V2G Programs
All data, patent claims, and statistics on this page are sourced from the references above and from PatSnap's proprietary innovation intelligence platform. Patent analysis conducted via PatSnap Eureka across Korean, US, Chinese, European, and international jurisdictions.
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