Partnership Develops Tech To Cut Active Suspension Size, Weight, Cost

Forbes

21-05-2025

Close up of car wheel on a road in very bad condition with big potholes full of dirty rain water ... More pools.
A new partnership aims to make a comfort feature generally available only in luxury vehicles, smaller and less expensive enough to be offered in more affordable models.
That feature is called active suspension. As opposed to what's known as passive suspension using shock absorbers and springs, active suspension does a better job absorbing road bumps and other inconsistencies and providing a quieter ride using electronic components and sensors.
The problem is, active suspension systems are heavier and more expensive. They also require 10-15 kilowatts of power, requiring large and heavy DC-to-DC power converters.
But a partnership between Andover, Massachusetts-based Vicor and Chinese tech firm Xiamen Hongfa Electroacoustic Co., Ltd., better known as Hongfa, is combining their expertise to solve those issues, the companies announced Wednesday.
Hongfa has designed the smallest and lightest active suspension system on the market by combining a ... More 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.
Hongfa, a leading manufacturer of power relays, developed a compact, lightweight active suspension system using much less power by incorporating high-density, small, lightweight power modules produced by Vicor. The systems also use regenerative power to reduce the load on a vehicle's battery—an important feature for battery electric vehicles.
The Hongfa active suspension system is liquid cooled and is the most compact on the market, weighing ... More 2.6kg and measuring 197 x 201 x 71mm, according to the company.
Indeed, the concept leverages the 48 volt networks replacing 12 volt systems in today's electrified vehicles aimed at improving efficiency and reducing vehicle size and weight.
It's a power level considered safe for anyone servicing a vehicle, and also allows a major reduction in the size of active suspension system actuators.
Greg Green, director, automotive marketing at Vicor
'What was needed was a power system that has very fast transients—it can rapidly switch from low power to high power, but more importantly, one that could switch from putting power into the actuator to accepting power out of the actuator so it can go back into the battery, and that's what our BCM 6135 does, and that's what Hongfa is leveraging to move forward in their system,' explained, in an interview.
'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. Vicor's BCM 6135 power modules enable the competitive performance we need,' said Peter Li, research & development director at Hongfa, in a statement.
Indeed the speed at reversing direction to capture regenerative power is key to reducing the overall size of the system and draw on the vehicle's battery.
Vicor BCM6135 DC-DC converter transient response is 8 million amps per second, a rate essential to ... More support optimal energy recuperation and storage for Hongfa's active suspension system
Here's how it works in an active suspension system, according to Vicor.
The vehicle's 800 volt battery provides current when the vehicle travels over smooth road surfaces, and the suspension actuation motor is the 48 volt load.
When the vehicle travels over a bumpy road, the linear motors in the suspension system momentarily become generators, which increase the voltage on the low side of the converter.
That's then multiplied by the conversion ratio of the converter, in this case 16-to-1, increasing the voltage on the input side above the 800 volt battery voltage.
This difference in voltage reverses the direction of current flow. The 800V battery then momentarily becomes the load and recovers energy by charging through its battery management control system.
Once the displacement from the bumpy road subsides, the bus converter once again steps down the 800 volt battery and supply current to the suspension linear motors – all without intervention from the vehicle's onboard processors.
It all happens with half the equipment normally required to capture regenerative energy since Vicor's BCM 6135 DC-to-DC converter is what Green describes as "symmetrically bi-directional, so it does roughly three kilowatts down, and it does three kilowatts up, so you don't have to add additional devices for the regenerative aspect, and regenerative is very important, because it's a lot of power and you want to get it back into the battery."
The results could mean a benefit for EV drivers looking to squeeze more driving range from their vehicles' batteries.
'You get a small range increase because of the weight decrease, but also because of the power regeneration, recapturing the power,' said Green. 'Essentially any suspension event, you're only consuming three to 4% of the total power that was put in, and then 96% or so gets put back into the battery. So you're not really consuming battery range, whether it's a plug-in hybrid or BEV in order to drive the suspension.'
Green expects the first use of the active suspension system incorporating Vicor and Hongfa technology to reach consumers around the end of 2026 or 2027—the 2028 and 2029 model years, mainly in luxury and mid-luxury vehicles. But within about 15 years, it could become ubiquitous across a wider vehicle price range as high-volume production results in lower costs.
Of course, with Hongfa being located in China, the question comes up regarding import tariff considerations. But it's an issue Green predicts will have little impact, pointing out Vicor ships its U.S.-made power modules to Hongfa, which builds the finished product.
'We see a little impact, of course, in some of the stuff that we buy,' said Green. 'But you know, this is a made in America product. So, yeah, there's some tariff issues going on, but I would say by the time we're actually live, those will be resolved.'