Wiznet makers

20 kW Bidirectional Wireless Charging for a Medium-Duty Truck: A WIZnet-Connected Ground-to-Vehicle DSP Network

Summary

A U.S. DOE–funded consortium led by CALSTART and ORNL integrated 20 kW bidirectional wireless charging into a medium-duty delivery truck. SPI-connected WIZnet Ethernet modules linked the ground- and vehicle-side DSPs to industrial Wi-Fi bridges, carrying vehicle battery status across the charging air gap.

Overview

The project developed a high-power bidirectional wireless power-transfer system for Class 5 and Class 6 medium-duty plug-in hybrid delivery trucks.

Its objectives included:

Charging a vehicle without a conductive cable

Returning energy from the vehicle battery to the grid

Supporting the approximately 11-inch ground clearance of a delivery truck

Connecting stationary energy storage to the ground-side DC link

Enabling several power-flow paths among the grid, stationary battery, and vehicle

Preparing for future fleet and microgrid energy management

Exchanging operating status between the ground- and vehicle-side power controllers

Vehicle-side hardware was integrated into a Workhorse plug-in hybrid step van and tested at ORNL. During the first two budget periods, the team completed converter development, Double-D coils, the LCC-LCC resonant network, DSP control, hardware-in-the-loop testing, and vehicle integration.

The research platform combined:

A 480 V three-phase grid connection

A bidirectional grid-interface converter

A stationary energy-storage system

A ground-side high-frequency inverter/rectifier

Double-D wireless-power couplers

A double-sided LCC-LCC resonant network

A vehicle-side rectifier/inverter

A 60 kWh vehicle battery

Ground- and vehicle-side DSP controllers

CAN communication with the vehicle BMS

WIZnet Ethernet interfaces

Industrial Wi-Fi bridges across the vehicle-to-ground gap

The project was therefore more than a wireless battery charger. It was a distributed energy system capable of coordinating the grid, stationary storage, and a vehicle battery.

How the Research Consortium Operated

U.S. Department of Energy and NETL

DOE established the technical objectives, budget periods, and project milestones. The related peer-reviewed publication states that the project was funded by the DOE Vehicle Technologies Office and managed through NETL. (Oak Ridge National Laboratory)

BP1 and BP2 were completed. The planned BP3 field demonstration was not completed.

CALSTART

CALSTART was the formal recipient organization and the project’s programmatic coordinator.

CALSTART is a U.S. nonprofit organization that supports clean-transportation technology development, demonstration, assessment, validation, market acceleration, and policy programs. It connects government agencies, research organizations, fleets, manufacturers, and technology companies. (CALSTART)

Its role in this project can be understood as coordinating:

The federal award and consortium

Research and industry participants

The delivery-fleet use case

Demonstration planning

Fleet-level benefit and business-case analysis

The transition from laboratory research toward market deployment

Oak Ridge National Laboratory

ORNL led much of the core technical research.

ORNL is a multiprogram national laboratory managed by UT-Battelle for the U.S. Department of Energy. Its work is primarily open research, and its facilities support collaboration with universities, government organizations, and industry. The Electrification and Energy Infrastructures Division conducts research in power electronics, energy storage, grid controls, and advanced energy systems. (Oak Ridge National Laboratory)

ORNL’s work in this project included:

Ground- and vehicle-side converters

Double-D coil and magnetic design

LCC-LCC compensation

Modeling and simulation

DSP control

Hardware-in-the-loop testing

Vehicle integration

Laboratory testing

Efficiency and operating-mode characterization

University of Tennessee, Knoxville

UTK was not listed as a primary consortium company in the final report, but Leon M. Tolbert of UTK co-authored the 2024 peer-reviewed system paper.

Tolbert’s research covers power electronics, wide-bandgap devices, microgrids, electric vehicles, and interfaces with distributed energy resources. He is also an adjunct participant at ORNL. This academic connection supports the project’s extension from vehicle charging into grid-connected converters and microgrid integration. (Tennessee ECE)

Industrial and Fleet Partners

The final report does not identify a specific Cisco hardware, protocol, or cybersecurity deliverable. The communication bridge or WIZnet implementation should not be attributed to Cisco without additional evidence.

Key Researchers

Omer C. Onar

Omer C. Onar was the report’s scientific and technical contact.

His ORNL research covers wireless power transfer, advanced power electronics, electric drives, energy storage, and smart-grid systems. He has also held technical and editorial roles within IEEE power-electronics and transportation-electrification communities. (Oak Ridge National Laboratory)

Authors of the Peer-Reviewed System Paper

The ORNL team continued developing higher-power WPT systems after this project, including separate 100 kW and later-generation research programs. Those results are not part of the original 20 kW truck system, but they demonstrate a continuing institutional research program. (Oak Ridge National Laboratory)

What Was Developed?

Three-Phase Grid
       │
       ▼
Grid Interface PFC / Inverter
       │
       ├──────── Stationary Energy Storage
       │
       ▼
Ground-Side HF Inverter / Rectifier
       │
       ▼
Primary LCC Network + Double-D Coil
       ║
       ║  11-inch magnetic air gap
       ║
       ▼
Secondary Double-D Coil + LCC Network
       │
       ▼
Vehicle-Side Rectifier / HF Inverter
       │
       ▼
60 kWh Vehicle Battery

The hardware supported several energy-flow paths:

Grid → Vehicle
Vehicle → Grid
Stationary Battery → Vehicle
Vehicle → Stationary Battery
Stationary Battery → Grid + Vehicle

Figure 16 on report page 27 presents the complete grid-connected circuit. Figure 17 on page 28 shows the physical ground assembly, vehicle assembly, Workhorse truck, and underbody wireless-power coil.

Project at a Glance

The controller designation is reproduced as written in the report rather than silently replaced with another Texas Instruments part number. System parameters are listed in Table IV on report page 28.

Wireless-Power Hardware

Double-D Couplers

The primary and secondary couplers used a Double-D geometry with ferrite tiles and aluminum shielding.

Dimensions: 34 × 28.5 × 1.5 inches

Primary winding: seven turns

Secondary winding: six and a half turns

Air gap: 11 inches

Coupling coefficient: 0.211

Nominal frequency: 22 kHz

Figures 6 and 7 on report page 15 show the coil geometry and simulated magnetic-field distribution.

LCC-LCC Resonant Network

Both sides used LCC resonant compensation.

The ground-side DC bus operated at approximately 675–800 V, while the vehicle battery operated at approximately 320–420 V. The resonant network was designed to support both G2V and V2G under these asymmetric voltage conditions.

Control Architecture

Grid-to-Vehicle

In G2V mode, the controller used target battery power or current and measured battery values to determine the primary DC-bus reference.

Grid interface: PFC rectifier

Ground HF stage: Inverter

Vehicle HF stage: Rectifier

Battery control: Constant-power charging

Grid current: Near-unity power factor

Protection: Overvoltage and overcurrent

Figure 11 on report page 20 presents the G2V control structure.

Vehicle-to-Grid

In V2G mode, the vehicle-side converter operated as a high-frequency inverter and the grid interface returned synchronized power to the grid.

Vehicle discharge-power reference

Primary DC-bus regulation

Active and reactive grid-current control

Battery SoC monitoring

Discharge termination below 30% SoC

Overvoltage and overcurrent protection

Figure 12 on report page 22 presents the V2G control structure.

Role of the WIZnet Ethernet Modules

WIZnet Was Used in the Communication Path, Not the 20 kW Power Path

Power Path
Grid / SESS ⇄ Power Converters ⇄ Magnetic Coils ⇄ Vehicle Battery

Communication Path
Ground DSP ⇄ WIZnet Ethernet ⇄ Industrial Wi-Fi Bridge
                    ))) Wireless Link (((
Vehicle DSP ⇄ WIZnet Ethernet ⇄ Industrial Wi-Fi Bridge

The report states that a WIZnet module was connected to the SPI interface of each ground- and vehicle-side DSP.

The Ethernet output on each side was connected to a BB-ABDN-ER-IN5010 dual-band industrial Ethernet bridge/router, creating the wireless link between the ground and vehicle assemblies.

Confirmed Data Flow

The vehicle BMS broadcast:

Battery voltage

Battery current

State of charge

Battery temperature

Additional battery-status data

The vehicle-side DSP read this information through CAN and transmitted it to the ground side through the WIZnet and industrial wireless path.

The report also describes a possible extension to a larger energy-management system capable of sending:

Charge commands

Discharge commands

Reference power levels

Vehicle and grid operating modes

These are proposed extension capabilities, not proof that a complete fleet-command protocol was validated at a UPS site.

Exact WIZnet Product Is Not Disclosed

The public materials do not identify:

The exact WIZnet product or chip

Firmware revision

TCP or UDP

Packet format

Socket count

Socket or network library

Update interval

Latency or jitter

Reconnection behavior

Authentication or encryption

The correct description is:

Each ground- and vehicle-side DSP used an SPI-connected WIZnet Ethernet module, but the exact product and application protocol were not disclosed.

The system should not be described as a confirmed W5500, WIZ850io, or WIZ750SR implementation.

Why This Project Is Relevant to WIZnet

A Rare High-Power Power-Electronics Use Case

The project expands the WIZnet application story beyond conventional IoT, serial gateways, and cloud-connected devices.

Relevant areas include:

Bidirectional power converters

Wireless EV charging

Vehicle-to-grid

BMS data transport

EVSE controllers

Fleet microgrids

Converter HIL systems

WIZnet was not the power semiconductor or wireless-power coil. It provided the IP communication boundary between two DSP-controlled high-power assemblies.

Separation Between Power Control and Wireless Transport

A power-control DSP must prioritize ADC sampling, current and voltage loops, PWM generation, protection, and fault shutdown.

In this system, WIZnet created a standard Ethernet endpoint, while a separate industrial bridge handled the wireless transport.

Time-Critical Power Control
DSP · ADC · PWM · Protection
              │
              ▼
WIZnet Ethernet Boundary
              │
              ▼
Replaceable Wireless Transport

Potential architectural benefits include:

Reduced DSP-board redesign when the radio changes

Wired Ethernet inside each control cabinet

Cable-based bench testing before wireless operation

IP abstraction of the ground and vehicle controllers

Easier integration with HIL, loggers, or secure gateways

Separation of converter-control and network-transport responsibilities

These are architectural inferences from the published structure. The report does not publish deterministic-latency, packet-loss, or fail-safe-networking measurements.

Strongest Near-Term Value: Research and Test Systems

Because the exact product, automotive qualification, and long-term field results are not public, the project should not be presented as a production-vehicle design win.

Its most direct relevance is to:

University power-electronics laboratories

National laboratories

EVSE prototypes

Converter HIL systems

Battery emulators

Microgrid testbeds

Stationary-storage controllers

Industrial charging demonstrators

A Control-Layer Use Case Rather Than Charger-to-Cloud Backhaul

A conventional OCPP module connects an EV charger to a cloud-based CSMS.

This project uses Ethernet at a lower control layer:

Typical EV Charging Backhaul
EVSE ⇄ CSMS / Cloud

This Research
Ground Power DSP ⇄ Vehicle Power DSP

The WIZnet interface is closer to the BMS and power converters than to billing or cloud operations.

Five Tested Energy-Flow Modes

Table V on report page 31 provides voltage, current, power, efficiency, and power-factor measurements for all five operating modes.

Interpreting the Efficiency Results

The executive summary reports greater than 95% efficiency during selected 20 kW bidirectional DC-to-DC tests.

The complete integrated modes, including additional converter stages, produced efficiencies from approximately 89.1% to 98.8%.

The safest interpretation is:

Selected resonant or DC-to-DC subsystem tests exceeded 95% at 20 kW, while complete integrated operating modes achieved approximately 89.1–98.8%, depending on the energy path and test conditions.

These power and efficiency values characterize the converter and wireless-power system, not the WIZnet communication performance.

What Was Actually Demonstrated?

Completed

Power-converter modeling and simulation

Grid-side and vehicle-side converter development

Double-D coil fabrication

LCC-LCC resonant-network development

Ground- and vehicle-side DSP control

Hardware-in-the-loop testing

Workhorse truck integration

ORNL laboratory vehicle testing

G2V and V2G operation

Stationary-storage integration

Five energy-flow modes

Ground-to-vehicle wireless communication

Not Completed

Long-term UPS depot operation

Roswell, Georgia field demonstration

Commercial fleet pilot

Multi-vehicle aggregation

Long-duration unattended operation

Production automotive qualification

Commercial EVSE certification

Why the Planned UPS Demonstration Was Not Completed

Budget Period 3 was intended to place the integrated vehicle and grid-side EVSE at a UPS site.

The final report attributes the cancellation to several factors:

COVID-19 travel and coordination interruptions

A change in the proposed UPS demonstration site

Revised site-preparation requirements

Safety and liability concerns

Company-wide layoffs

Reduced partner resources

A change in UPS’s near-term wireless-charging plans

Reassessment of the technology’s commercial relevance

DOE, NETL, and the partners agreed to rely on the extensive ORNL laboratory results instead of completing the site demonstration.

The project should therefore be described as a vehicle-integrated, laboratory-validated research platform, not as a deployed UPS fleet system.

Publications and External Research Value

The final report lists three conference papers and two journal articles generated by the project.

The principal journal publications include:

Bidirectional LCC–LCC-Compensated 20-kW Wireless Power Transfer System for Medium-Duty Vehicle Charging
IEEE Transactions on Transportation Electrification, 2021

Medium-Duty Delivery Truck Integrated Bidirectional Wireless Power Transfer System With Grid and Stationary Energy Storage System Connectivity
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2024
DOI 10.1109/JESTPE.2024.3429509

The 2024 article reports 20 kW transfer across an 11-inch air gap, 93.02% G2V efficiency, and 89.08% V2G efficiency. (Oak Ridge National Laboratory)

The public project-output list does not identify a patent from this specific grant. The system should not be described as patented WIZnet wireless-charging technology without separate patent evidence.

Related WIZnet Maker Projects

1. Full-Featured OCPP Module

This Maker Site content presents a connectivity module combining ESP32 Wi-Fi, W5500 Ethernet, and cellular networking for EVSE-to-OCPP-backend communication. (Wiznet Maker)

Difference

OCPP module: EVSE to cloud/CSMS

DOE WPT system: Ground power DSP to vehicle power DSP

OCPP module: Operations, billing, and backend communication

DOE system: BMS telemetry and local power-control communication

2. EthWiFiManager

EthWiFiManager manages Ethernet-first connectivity with Wi-Fi as an alternate network path on ESP32 systems. (Wiznet Maker)

Difference

EthWiFiManager: One MCU manages Ethernet and Wi-Fi

DOE system: Two DSPs use Ethernet endpoints and separate industrial wireless bridges

EthWiFiManager: General connectivity layer

DOE system: Vehicle-to-ground communication between high-voltage converters

3. ESP32-Edge-Device

ESP32-Edge-Device uses ESP32 and W5500 for power measurement, relay protection, MQTT, and Modbus TCP. (Wiznet Maker)

Difference

ESP32-Edge-Device: Low-voltage edge monitoring

DOE WPT system: Bidirectional high-voltage converter and vehicle-grid control

ESP32-Edge-Device: One embedded node

DOE WPT system: Physically separated ground- and vehicle-side DSP controllers

Comparison at a Glance

Potential Follow-Up Directions

Modern DSP-to-Ethernet Reference Design

A modern laboratory reference could combine:

A TI C2000-class power-control DSP

A current WIZnet SPI Ethernet module

CAN-to-Ethernet BMS transport

TCP and UDP reference protocols

Heartbeat and link supervision

Reconnection measurement

Link-loss fail-safe behavior

HIL test scripts

Wired and wireless-bridge operating modes

This would be a new reference design. It would not prove that any current WIZnet module was used in the original project or that it is automotive-qualified.

Secure Charging-Control Plane

The project objectives mentioned cybersecurity provisions, but the final report does not publish the implementation details.

A modern design could evaluate:

Mutual authentication

Message integrity

Replay protection

Key management

Secure boot

Signed firmware updates

Network segmentation

Local fail-safe operation independent of the wireless link

Fleet and Microgrid Gateway

A higher-level gateway could integrate:

Multiple charging pads

Vehicle identity

Vehicle and stationary-storage SoC

Site load limits

Electricity prices

Renewable generation

OCPP backend communication

Local V2G aggregation

The report’s conclusion similarly proposes centralized energy management based on battery state of charge and grid pricing.

Open Questions and Limitations

Communication Details Not Disclosed

Exact WIZnet model and chip

Firmware source

Socket or network library

TCP or UDP

Packet structure

Update rate

Latency and jitter

Packet-loss rate

Reconnection time

Link-loss behavior

Authentication and encryption

Qualification Not Established

Automotive production qualification

AEC-Q component qualification

SAE WPT interoperability certification

Commercial EVSE certification

Public-grid interconnection approval

Long-term fleet uptime

Multi-vehicle depot operation

Environmental and vibration qualification

Safety Communication

The report documents converter overvoltage, overcurrent, and low-SoC protection. It does not explain the complete safe-state sequence following loss of the wireless communication link.

The system should not be described as a safety-certified or cybersecurity-validated communication platform.

Connecting with the Research Team

Omer Onar and the ORNL team remain active in wireless power, power electronics, and grid-integration research. CALSTART contributes a complementary perspective on technology demonstration and market deployment. (Oak Ridge National Laboratory)

A technical interview could address:

The exact WIZnet product and chip

Why SPI Ethernet was selected for the DSP

Whether TCP or UDP was used

BMS packet format and update rate

Measured latency, jitter, and packet loss

Safe-state behavior after wireless-link loss

Socket-library usage

Cybersecurity implementation

HIL disconnect and reconnect testing

How the network would be redesigned with current hardware

Interest in a public WIZnet-based laboratory reference design

CALSTART could also explain the gap between laboratory success and fleet deployment, the lessons from the canceled UPS demonstration, and the requirements of a future commercial pilot.

Conclusion

The DOE-funded project integrated a 20 kW-class bidirectional wireless power-transfer system into a Workhorse medium-duty plug-in hybrid delivery truck.

The power system included:

A 480 V three-phase grid

Stationary energy storage

Bidirectional power converters

Double-D magnetic couplers

An LCC-LCC resonant network

An 11-inch air gap

A 60 kWh vehicle battery

The communication system included:

A ground-side DSP

A vehicle-side DSP

One SPI-connected WIZnet Ethernet module on each side

Two industrial Ethernet-to-Wi-Fi bridges

CAN-based vehicle BMS data

Vehicle-to-ground wireless communication

Five energy-flow modes were tested. Grid-to-vehicle operation delivered 20.363 kW to the vehicle battery at 93.02% overall efficiency. Vehicle-to-grid operation delivered 12.821 kW to the grid at 89.088% overall efficiency.

The planned UPS field demonstration was not completed. The project should therefore be presented as an ORNL vehicle-integrated and laboratory-validated research platform, not as a commercial fleet deployment.

The central WIZnet message is:

WIZnet did not transfer the 20 kW of wireless power. It connected the ground- and vehicle-side power-converter DSPs to Ethernet, creating a communication path for BMS status and future energy-management commands across an industrial wireless bridge.

This makes the project a rare research reference for WIZnet Ethernet in EVSE, V2G, energy storage, converter HIL, and fleet-microgrid control systems.

FAQ

Q. Is the source a patent or a research paper?
A. The OSTI source is a DOE Final Scientific/Technical Report. A separate peer-reviewed 2024 IEEE journal article reports the integrated technical results.

Q. Did WIZnet transfer the 20 kW of wireless power?
A. No. The power path used converters, the LCC-LCC resonant network, and magnetic coils. WIZnet provided the Ethernet communication path for the two controllers.

Q. Which WIZnet product was used?
A. The report does not identify the model. It states only that a WIZnet Ethernet module was connected to the SPI interface of each DSP.

Q. What data was carried over the network?
A. Vehicle BMS voltage, current, state of charge, temperature, and other status data were read through CAN and transmitted to the ground side. Charge, discharge, and power-reference commands were described as future energy-management extensions.

Q. Why were Ethernet and Wi-Fi both used?
A. WIZnet provided a wired Ethernet interface to each DSP. Separate industrial bridges transported that Ethernet traffic wirelessly between the ground and vehicle assemblies.

Q. Was the system operated at a UPS depot?
A. No. Vehicle integration and laboratory testing were completed at ORNL, but the planned UPS field demonstration was canceled.

Q. Can this be presented as an automotive production design win?
A. No. It is a strong research and HIL reference, but the exact product, automotive qualification, long-term reliability, cybersecurity, and fleet deployment were not publicly established.

Source Snapshot

This source is not a patent. It is the Final Scientific/Technical Report for a U.S. Department of Energy–funded research project. CALSTART was the recipient organization, with ORNL, Cisco Systems, Workhorse, and UPS identified as project partners.

The final integrated technical results were also published in a peer-reviewed 2024 article in the IEEE Journal of Emerging and Selected Topics in Power Electronics. The article reports the 20 kW transfer system, 11-inch air gap, stationary energy-storage connection, and five energy-flow modes. (Oak Ridge National Laboratory)

Source and copyright note: This curation independently paraphrases the OSTI report and official institutional sources. It does not reproduce report text, tables, or figures. OSTI states that public access does not automatically place hosted material in the public domain. References to commercial companies and products also do not imply endorsement by DOE or the U.S. government. (OSTI)