Xiamen Hongfa Electroacoustic Co., Ltd (Hongfa) has designed the industry’s highest performance and smallest active suspension power system with a goal to drive what has been a long-time luxury feature into the midrange vehicle class. Overcoming decades of false starts by prominent automotive technology providers, Hongfa struck a balance between the need to manage active suspension system size, weight and transient performance against the requirement for higher efficiency, improved EMI and symmetrical regenerative power capacity.
As an automotive power management and distribution specialist, whose relays are enabling new 48V zonal architectures, Hongfa partnered with Vicor to integrate a fixed-ratio 800V-48V DC-DC converter power module that sits alongside a network of sensors, electromechanical actuators and sophisticated software to adjust vehicle suspension in real time. The collaboration yielded the smallest active suspension system – almost half the size of the nearest competitor – with the industry’s fastest power conversion transient response.
High-voltage batteries and a 48V PDN trigger a revolution for the Hongfa active suspension vision
Whether a vehicle is on a worn highway, a backcountry dirt lane or navigating suburban potholes, active suspension provides better handling, a smoother, safer ride and reduced road noise. Early industry efforts in the 1970s included a complex electromagnetic solution which strained the capabilities of 12V battery power systems and required four 200-pound motors.
Historically, 12VDC has proven to be inadequate for powering active suspension motors without adding size, weight and cost. Additionally, some conventional DC-DC converters can deliver power without the need for an intermediate battery, but the tradeoff is that they are bulky and lack the fast transient response time required to meet the regenerative demands to recoup and store power.
Despite a history of power-hungry, heavy loads, active suspension systems stand to benefit from today’s higher voltage (400V or 800V) primary batteries and the industry’s adoption of 48V power delivery networks (PDNs); a combination is already powering plug-in hybrids and BEVs.
Vicor fixed-ratio 800V to 48V DC-DC BCM bus converters are inherently bidirectional and provide the fastest transient response (8 million amps/second) of any DC-DC converter topology. BCMs also offer symmetrical bidirectional performance with the ability to buck or boost with the same power level. Their advanced planar packaging simplifies thermal management system design, further reducing overall footprint and weight.
Linking active suspension directly to the main battery with a bidirectional power converter enables optimal energy recuperation. Similar to how a spring absorbs and releases energy, active suspension uses regenerative shock absorbers to collect kinetic energy that is returned to the battery.
Hongfa introduces smallest active suspension system using power modules and 48V
The Hongfa solution leverages Vicor high-density power modules to create a compact (197 x 201 x 71mm) 5kW power supply for each actuator. The system can rapidly process up to 6kW of peak power in either direction. The design of the converter is greatly simplified by using a pair of Vicor BCM6135 modules operating in parallel, instead of several hundred discrete components.
The converter is optimized to work with 800V battery systems and has an operating range between 420V to 920V. With liquid cooling it can deliver up to 100A of current with 97.3% efficiency. The system housing volume is under 1.8l and weighs 2.6kg, providing a major reduction over other systems.
“When it comes to active suspension, our OEM customers require a DC-DC converter with a response rate measured in milliseconds, otherwise, additional battery support is needed,” said Peter Li, Director of Research and Development at Hongfa. “Vicor’s BCM6135 power modules not only delivered the performance we need, they also significantly shortened our development time and have made designing this system much easier for us.”
The combination of 48V and high-density power modules is enabling new levels of innovation in automotive electrification – reducing space, weight and providing superior performance. Together, Hongfa and Vicor are leveraging their automotive expertise to develop advanced technology and support the evolution of high-performing electric vehicles.
