Electric Vehicles and Smart Mobility

The Electric Vehicles and Smart Mobility (EVSM) group conducts impactful research in the intersection area of power electronics, electric vehicles and transportation systems, with emphasis on the system integration, new energy source, electric propulsion, high-power chargers, wireless power transfer, vehicular energy network, intelligent transportation, public transportation and smart mobility. Both basic and translational researches mingle with good balance. Major projects are funded by RGC’s Theme-based Research Scheme and General Research Fund, ITC’s Innovation and Technology Fund as well as other research grants and contracts.

•    Ammonia-Powered Electric Vehicles
The ammonia-powered EV is a ground-breaking innovation developed by PolyU, which has gained worldwide recognition as the first-ever of its kind. This remarkable achievement has been made possible through the support of the Innovation and Technology Fund. PolyU has successfully built two vehicle prototypes, including a light vehicle and a mini-bus, showcasing the immense potential of ammonia as a sustainable fuel source in the realm of electric transportation and also contributing to the development of carbon neutrality research.

•    In-Wheel Motor Drives for Electric Vehicles
Using in-wheel motor drives is promising for EV propulsion, which can significantly improve vehicle interior space and dynamic response. In PolyU, novel ironless in-wheel motor drives are developed. Because of the ironless structure, it can reduce the motor weight and size. Meanwhile, the ironless feature can eliminate core loss, thus higher efficiency can be achieved throughout the whole speed range. Benefiting from weight reduction and efficiency improvement, the developed motor drives can greatly improve the driving comfort and mileage.
 
•    Magnetic Differentials for Electric Vehicles
The vehicular differential system plays an important role in propulsion. Mechanical differential is robust, but suffering from gear problems; whereas electronic differential is accurate and efficient, but suffering from reliability concerns. A novel magnetic differential system is developed, which can provide accurate and efficient differential action while solving reliability concerns. The key is to utilize the magnetic steering field to interact with the permanent-magnet fields in the two rotors of the double-rotor motor. Hence, the differential torque can be generated between wheels to achieve accurate cornering during vehicle steering.
 
•    High-Power-Density High-Efficiency On-Board Chargers for Electric Vehicles
In collaboration with The Third-Generation Wide-Bandgap Power Module Packaging and System Integration Joint Engineering Center, The Songshan Lake Materials Laboratory, the project aims to develop a high-power-density high-efficiency on-board charger for EVs. In comparison to the existing silicon carbide (SiC) modules, the proposed high-temperature SiC module can withstand at least 25% higher maximum junction temperature, leading to a simplified cooling system design and enabling a more compact and economical on-board charger solution. A further reduction in size, weight and cost is achieved by proposing a novel single-stage high-power AC-DC converter topology that utilizes at least 50% less switches compared to the existing topologies.
 
•    Electric Vertical Take-Off and Landing (EVTOL) for Electric Aircraft
An EVTOL aircraft uses electric power to hover, take off, and land vertically. Currently, there is a huge demand for the development of EVTOL in many countries, such as the USA, Canada, Europe and the UK, aiming to match with the stringent requirement of carbon neutrality by 2050. In PolyU, the development of the first-generation EVTOL propulsion in Hong Kong is launched. The proposed design can satisfy the maximum power of 100-200 kW, lift force of 500-1000 kg, and flight duration of 10-15 mins. A single propeller prototype is being tested at the Industrial Centre of PolyU.
 
•    Wireless Power Transfer (WPT) and Wireless Energy Conversion
WPT takes the definite advantages of high flexibility, high convenience and free from electrocution. In PolyU, wireless energy conversion systems, including wireless chargers (electrical to chemical), wireless lamps (electrical to optical), wireless heaters (electrical to thermal) and wireless motors (electrical to mechanical), are actively developed. Specifically, compact and integrated single-phase and three-phase AC-DC converter topologies with minimum active power device count are developed for WPT, aiming at achieving high input power quality, high efficiency, low cost and high power density.
 
•    Wireless Electric Vehicle Energy Network (WEVEN)
A novel concept of WEVEN is developed, which can offer more functionalities and opportunities for modern power grid while having high flexibility and reconfigurability. It can also artfully collaborate with the distributed renewable energy network, electrical power network, energy storage network and other energy networks for the Energy Internet. Apart from transporting passengers, the mobility of EVs is utilized to transmit electricity among various locations. The proposed wireless energy router can enable EVs exchanging and trading wireless energy packets at road junctions or on electrified roadways.
 
•    Intelligent transportation systems
Innovative solutions have been proposed for better informed and more efficient transportation operation and management. The topics include predictions of network-level traffic state using data-driven and deep learning technologies; urban traffic signal control driven by emerging data sources, AI and digital twin; cooperative conflict-free on-ramp merging for connected autonomous vehicles based on mathematical programming and deep learning; modelling of pedestrian mobility patterns in urban environments with Bluetooth sensor technology; etc.
 
•    Bus systems
Modeling, analysis, optimization and AI techniques have been utilized to achieve a more efficient and sustainable bus system and enhance the bus service quality. The research ranges from design of bus networks and services; planning, scheduling and management of zero-emission bus services; to scheduling of opportunity charging of electric buses; bus queuing analysis; and prediction of bus arrival times.
 
•    Railway systems
The focuses are on the planning, management and operation of the railway systems for improving their efficiency and sustainability. The studies cover the planning and scheduling of railway services, eco-driving technology for energy saving, modularized trains, virtual coupling, and autonomous train driving.