Highly integrated GaN power converter to calm the interference

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In various systems that underpin people's living condition, movement and communication, we need power electronics converters to transfer electrical energy. For example, they can transfer almost constant voltage and current generated from a solar panel to the power grid, where the voltage and current are alternating polarities. They can also transfer alternating voltage from household power sockets to charge electric vehicles, smart phones and laptops, where the voltage of the batteries is almost constant. As the electricity is generated from a combination of sources (fossil fuel and renewable energy), the efficiency of the power electronics converters plays a vital role to reduce CO2 emission for Net Zero and sustainable development. The operation of the power electronics converters relies on the semiconductor transistors. A power electronics converter usually has 6 or more transistors. Each transistor works like a "switch" to turn on and off repeatedly following certain control patterns. When a transistor switches from one state to another, there is an overlap of voltage and current across it which causes power losses. If the efficiency of power electronics converters needs to be improved, each transistor's transition should be reduced. A recently developed transistor based on emerging gallium nitride (GaN) materials demonstrate the capability to transfer the kilowatt power during nanoseconds, which reduces the power losses more than 10 times in comparison to a traditional transistor based on silicon. However, the fast power transition comes with the challenge of the electromagnetic noise, which will propagate from one transistor to another, and from a high power circuit to a low power control circuit for control patterns generation. Consequently, the transistor will withstand higher voltage and current spikes that reduce their lifetime, and the low power circuit will generate wrong control patterns and make the whole converter fail to operate. Under the fast switching of GaN, the noise interference also reaches to a level that conventional approaches based on silicon transistors can no longer work. An ambitious target of the proposal is to reduce the noise interference by using a new design to connect multiple GaN transistors with their control circuits, and assemble them together in a power converter. We will first identify noise interference strength and polarity generated by each transistor, and then use the noise interference of the same strength but different polarities to cancel each other. Therefore, the total effective noise interference will reduce to almost zero in our proposed design, and power converter efficiency could be greatly improved. To achieve this ambitious design, a new partnership with French Ampere Lab will be developed and built via knowledge transfer and learning. The unique and global leading expertise of French Ampere Lab on 3D high-density packaging is crucial for the implementation of the design, and it will complement University of Nottingham team's expertise of power transistor application. Eventually, it will benefit UK and make UK a world leading role for emerging GaN power electronics technology that will underpin Net Zero and sustainable development.