Automobile active suspension system and integrated charger
In 2016, the value of the global car manufacturing industry is forecast to reach US$1,098 billion.
Automotive and its supply chain present tremendous potential as car owners keep upgrading their vehicles with electronic infotainment systems, smartphone connectivity and fuel economy.
Leveraging consumer demand, the Automotive Parts and Accessory Systems R & D Centre (or APAS in short) in Hong Kong keeps reinventing car components with groundbreaking designs.
Experts at APAS successfully developed a simple, cost-effective, lightweight, responsive active suspension system, alongside an integrated charger and motor drive system for electric vehicles. Both patented systems are available for licensing and commercialisation.
Electromagnetic active suspension system
Active suspension systems, as opposed to conventional passive systems, are able to adjust itself continuously according to the road condition. However, active suspension systems have appeared on high-end vehicles exclusively because of their complexity and hefty costs.
Currently, the most common systems are hydraulic or pneumatic in nature, only capable of controlling suspension over the low frequency range. That means hydraulic systems can never be fully active across the full bandwidth and they turn passive at high frequencies. They also pose pollution problems because hydraulic fluids are toxic.
Researchers at APAS spotted the possible advantages of an electromagnetic active suspension system which demonstrate superior all-round performance. The new active suspension system includes a linear switched reluctance actuator (LSRA), a spring, a controller, and a power converter to step up battery voltage and recover energy.
The direct-drive linear permanent magnet actuator provides forces directly to a payload in the absence of a gearbox or transmission system. The resulting system is simple in design with accurate and flexible force control. It is also more responsive and offer better handling than existing hydraulic active suspension system.
It costs and weighs a lot less because of its simple structure and few components while capable of operating in high bandwidths. In terms of energy consumption, it also outperforms its hydraulic counterparts because of the extra energy regenerated at braking and deceleration.
Integrated battery charger and motor drive system
Electric vehicles are great ways to get around because they don’t pollute the atmosphere like cars with internal combustion engines. However, they still haven’t caught on as the dominant choice because charging stations are few and far between and you can be stranded if you run out of battery in the middle of nowhere.
A portable backup battery would be great, but most electric vehicle batteries charge offline, meaning the car has to stay still before the battery starts charging and you can’t charge it on the road.
To address this dilemma, researchers at APAS invented an integrated battery charger and motor drive system which includes control programmes allowing an H-bridge converter shared between the charger and the motor control unit.
When the car comes to a stop, the converter automatically switches to charge the battery. When the car starts moving, the converter switches back to motor drive and stops charging automatically.
APAS is seeking entrepreneurs to commercialise these automotive technologies worldwide. There are many more projects in development and APAS looks forward to talking to automobile-related companies interested in incorporating their innovations in their upcoming products.
Contact information: laura.yu [at] isis.ox.ac.uk (Laura Yu)
• This article is part of the ‘ITF Projects Commercialisation Programme’ hosted by Hong Kong Science and Technology Parks Corporation (HKSTP) in conjunction with Isis Innovation, the technology transfer company of the University of Oxford. The programme aims to expose Hong Kong innovations to international audiences and hence, facilitate commercialisation via the network of Isis. For information on all projects in the programme, please visit
This project is organised by Hong Kong Science & Technology Parks Corporation. Any opinions, findings, conclusions or recommendations expressed in this material/event (or by members of the project team) do not reflect the views of the Government of Hong Kong Special Administrative Region, the Innovation and Technology Commission or the Vetting Committee of the General Support Programme of the Innovation and Technology Fund.