Cambridge GaN Devices (CGD) is working with engineering consultancy Ricardo on a gallium nitride traction inverter being developed within Nissan-led Project SUITE, a £10 million UK government-backed research programme focused on electric vehicle efficiency and energy integration.
The Cambridge semiconductor company will supply ICeGaN integrated power device technology and engineering expertise for Ricardo’s propulsion inverter design. Nissan leads the wider programme, combining work on conversion hardware with intelligent charging and renewable energy technologies. The collaboration remains in design and development, with prototype measurements and industrial production plans still to be reported.
Project SUITE is supported through the government’s DRIVE35 automotive programme and involves ten industry and academic partners. Nissan Technical Centre Europe in Cranfield is coordinating development, with the resulting technologies intended to be integrated into the British-built Nissan LEAF platform for testing. Its wider work also includes vehicle-integrated solar panels, an automated bidirectional charger, charging management software and forecasting tools.
A traction inverter sits between an electric vehicle’s high-voltage battery and its drive motor. It converts the battery’s direct current into controlled alternating-current waveforms, adjusting the electrical supply to deliver the torque and speed requested by the vehicle control system. The semiconductor switches inside the inverter determine how efficiently the converter can perform that task, while the surrounding design must handle current, heat, electrical noise and fault conditions.
Gallium nitride devices can operate at high switching speeds with comparatively low switching losses, potentially reducing converter energy dissipation and the size of associated passive components. A useful traction inverter nevertheless requires the switching strategy, electrical current, motor characteristics, semiconductor packaging, cooling and electromagnetic compatibility to be engineered together. Higher switching frequencies can increase electrical interference and complicate thermal management if those constraints are not addressed.
CGD’s ICeGaN technology combines a gallium nitride transistor with integrated control and protection functions designed to allow conventional gate-driver arrangements. The integration can reduce external circuitry while supporting the connection of multiple devices in parallel. That configuration is relevant where traction inverter current requirements exceed what can be handled economically or thermally by a single switching package.
Parallel operation makes consistent current sharing essential. When devices switch at slightly different times or carry unequal currents, one component can experience a greater electrical and thermal load than its neighbours, reducing the safe operating margin of the whole assembly. CGD claims its architecture supports balanced operation with five or more devices connected in parallel. The consortium has not yet reported the selected device configuration or measured efficiency and thermal characteristics of its inverter.
Ricardo contributes propulsion system design, integration and validation expertise. Temoc Rodriguez, Ricardo’s global technical expert in electric propulsion systems, has associated the work with five years of the consultancy’s research into high-power gallium nitride applications. The next engineering tasks will include translating the device-level approach into a manufacturable inverter, assessing thermal behaviour under load and validating performance with the chosen motor and battery architecture.
Nissan described the wider programme when it began in June as an effort to combine on-board energy generation, charging controls and more efficient conversion hardware in one vehicle. Its approach includes a charging system designed to coordinate electricity use and an automated device for bidirectional vehicle-to-grid connection. The inverter is one part of that architecture rather than a standalone solution to the project’s full charging and energy objectives.
In a vehicle-to-grid arrangement, energy can be transferred from a battery to an external electrical system when the hardware, connection and control strategy permit. Integration raises additional design questions, including protection, communication with charging equipment, battery operating limits and the way different energy conversion stages interact. The research programme is intended to explore these relationships in a combined demonstrator, but no commercial release date has been specified.
The programme also brings together specialists in power modules, photovoltaic technology, controller design, electrical networks and digital systems. Those interfaces are relevant to automotive industrialisation because a laboratory semiconductor design must ultimately be translated into a component that can be packaged, cooled, assembled, tested and serviced in a vehicle application. Repeatable electrical characteristics and manufacturing quality become as important as the peak performance observed in a prototype.
As the project advances, prototype measurements will establish the inverter’s switching losses, temperature distribution, electromagnetic performance and reliability through operating cycles. Those tests, followed by integration with Nissan’s demonstrator vehicles, will determine the suitability of the design for further automotive development. No production launch schedule has been disclosed.
