8 48V POWER INFUSIONS www.vicorpower.com Issue 3 2025 Power Electronics Europe www.power-mag.com Active suspension approaches on-ramp to more markets after 48V power infusion Hongfa solves age-old power challenge with 48V architecture and high-density power modules Vehicle electrification still grabs the lion’s share of automotive technology headlines, but active suspension systems are transforming the driving experience for millions of car owners. Joining the ranks of anti-lock brakes, lane-departure warnings and back-up cameras, active suspension technology, which is currently found only in luxury vehicles, is on the fast track to enter the mid-range auto market. Xiamen Hongfa Electroacoustic Co., Ltd. (Hongfa), one of the world’s largest manufacturers of power relays, has been advancing the automotive market for nearly three decades. Hongfa specializes in automotive power management and distribution, and they are squarely focused on the future of EVs and how to support better electrification in power systems. Hongfa relays are foundational to electric vehicle design and are enabling breakthrough developments where 48V networks are replacing 12V systems to improve efficiency and reduce vehicle size and weight. Hongfa is infusing its electrical hardware, software and structural design expertise to propel the next generation of xEVs. Among other innovations Hongfa has designed the highest performance and smallest active suspension power system on the market (Figure 1). Their bold, innovative design projects to soon make this long-time high-end feature common among mid-range vehicles, improving the ride and safety for more drivers. 48V and evolutionary power technology drive smaller systems and better performance Active suspension systems are highly complex. They use a network of sensors, electromechanical actuators and sophisticated software to adjust vehicle suspension in real time. This results in better handling, a smoother, safer ride and reduced road noise even under the worst road conditions—from navigating suburban potholes to a rural dirt road. Appreciating what Hongfa has achieved requires understanding the active suspension in its infancy. Starting in the 1970s active suspension used complicated electromagnetic solutions which strained the capabilities of 12V battery power systems. It required four 200-pound electromagnetic motors— adding an extra 800lbs to the vehicle, limiting mass adoption. Top technical challenges facing active suspension PDNs Generally, there are two options for the active suspension system power delivery network (PDN). First, the system can be connected directly to the high-voltage battery, which is the current standard for plug-in hybrid vehicles. Here, active suspension is linked directly to the car’s 800V battery, which is efficient and enables energy recuperation through regenerative charging. However, this architecture requires the OEM to run heavy, expensive high-voltage cables all around the car. Alternatively, active suspension can be achieved via the lower-voltage bus, which is either 12V or the increasingly popular 48V. Within the low-voltage option, systems can either rely on an intermediary battery or use DC-DC converters to step down the high-voltage battery rail for use in active suspension. For the latter, the technical revolve around: 1. Small system size. Today’s active suspension systems require 10 – 15kW of power, which traditionally requires a very large and heavy DC-DC converter to support this power level. 2. Rapid regenerative DC-DC converter speeds. Achieving energy recuperation in active suspension systems requires very dynamic, Figure 1 Hongfa has designed the smallest and lightest active suspension power delivery network on the market by combining a 48V architecture and high-density power modules. Four Vicor fixed-ratio BCM6135, 800V-to-48V DC-DC bus converters are used to convert high voltage to 48V and route power to each wheel. The BCM6135 is bidirectional and provides the fastest transient response of any DC-DC converter. This symmetrical switching speed enables optimal energy regeneration when directly linked to the DC-DC converter.
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