Automotive Electrification Requires Innovation to Deliver on OEM Promises
A module approach offers flexible, scalable and power dense solutions.
I had the chance to talk to Nicolas Richard, Director Automotive Business Development Europe at Vicor about the challenges the transition to Electro Mobility comes with and how Vicor will contribute with its technology and products.
Bodo: Automotive electrification is a hot topic, as it is expected to eliminate combustion engines in new vehicles by 2035 in Europe. What contribution will Vicor’s products make to the automotive industry?
Nicolas Richard: We certainly expect to see internal combustion engines running on fossil fuel being phased out in the EU by 2035. This means that, apart from specific use of synthetic fuels for instance, all vehicles will need to rely on electrification. All such vehicles use electronics to convert voltages at various ranges of power. Over the last few years, the power levels encountered by power delivery networks (or PDNs) have grown from a couple of kW to over 150 kW in some applications. This has been driven by growth in comfort loads and accessories like heated windshields, autonomous driving, charging interoperability - and accommodating these high-power demands is a big challenge for OEMs. High power from the primary battery (400V of 800V) is needed to accommodate fully battery electric vehicles (BEV). However, higher voltages present a bigger power conversion challenges when converting down to smaller point of load(s). These demands negatively impact energy efficiency, reliability and even comfort and safety as the added size and weight necessitate tradeoffs in vehicle features. There simply isn’t enough space to accommodate all the electrical requirements if car manufacturers proceed with traditional methods of power delivery. To meet this challenge, OEMs and Tier Ones will need to find a solution that is not only lightweight and compact, but is also flexible, scalable and power dense so it can be reused across the fleet.
Nicolas Richard. Image used courtesy of Bodo’s Power Systems [PDF]
Vicor has innovative power architectures, topologies and components to help OEMs develop EV platforms more quickly with greater flexibility. The Vicor modular approach takes fewer engineering resources, and ultimately allows OEMs to design power delivery networks resulting in higher performance vehicles.
Bodo: What technologies are needed to achieve more power in less space?
Nicolas: Vicor has been a leader in power-dense solutions for decades because of a holistic approach to solving difficult power challenges. Understanding the importance of these power system design challenges and key PDN performance specifications drives Vicor to constantly innovate to stay on the forefront of power systems technology. This helps OEMs to do the same.
This requires a major commitment to innovation on many levels - we base our approach on five pillars of power innovation.
The first is that we have proprietary power delivery architecture and are experts in how to optimize it. Secondly, we use unique power conversion technologies and topologies.
The third is the control systems that we develop in house to optimize the power efficiency of all our solutions.
The fourth pillar of innovation relates to high density power modules and the materials we use.
The last pillar is our thermally adept packaging which supports higher efficiency and better overall performance.
Vicor recently celebrated its 40th anniversary and this holistic approach have driven our success. In 2008, we introduced new innovations which enabled significant gains in power density over the brick and advanced its power component design methodology for the power systems industry. Some of the more impactful innovations include, Factorised Power Architecture (FPA™) and a new higher frequency topology called a Sine Amplitude Conversion (SAC™). We also introduced zero voltage switching (ZVS) and zero current switching (ZCS) topology while bringing new materials to the package.
In 2015 further improvements in control systems, topologies, components and materials enabled us to redesign the VI Chip® package to capitalize on further power-loss reductions, higher-frequency control systems and topologies with resulting gains in power and current density.
The new package was called the ChiP™ (Converter housed in Package), and its construction and manufacturing approach broke new ground at Vicor as well as in the power module manufacturing industry. The new ChiP package was distinguished by its two-sided component assembly while being cut from fixed-size panels, similar to how silicon chips are made and cut from wafers.
Vicor has also pushed the limits of magnetics and power engineering routinely, delivering the next generation of power-dense products for customers’ world-changing innovations. With this momentum and using the five pillars as a compass, the journey is nowhere near over.
One of our more popular parts is the BCM which is based on the SAC converter. Using zero-voltage, zero-current switching (ZVS/ ZCS), Vicor BCM bus converters operate at higher frequencies than conventional converters, making them more responsive than a physical battery in automotive low voltage battery replacement applications.
The BCM6135 runs at a high frequency of 1.2 megahertz and unlike the regular ZV/ZC resonant converters, it operates in a very narrow frequency band, allowing optimization of all the components inside the module to achieve maximum power density and efficiency.
The BCM’s high frequency operation provides a fast response to changes in load currents and a low impedance path from input to output. Fixed ratio conversion, bidirectional operation, fast transient response, and a low impedance path are the set of qualities that enable the BCM to serve a “virtual” battery.
Bodo: Which world-leading OEMs are being targeted by Vicor?
Nicolas: Every OEM can benefit from Vicor technology if they need to reduce weight, the size of power their electronics, and improve thermals.
Because our modules are so small, we can package anywhere in the vehicle. It’s currently a big challenge for OEMs to bring a new component such as a DC to DC converter to the system especially when the power is very high. Whether designing a high-performance sports car, a light-duty truck or a family car, OEMs need to pack as much power as possible into a constrained space. All vehicles need compact and efficient power solutions.
An electric vehicle (EV) can use up to 20X more electrical power than a traditional internal combustion engine (ICE) vehicle. That power increase requires proportional size and weight increase for the power electronics to convert and deliver all that power in an EV. There is just not enough space in the vehicles to package the power electronics. So, using a system with very high-power density, meaning a smaller, lighter PDN delivering the same power.
As fleets have many vehicles sharing a common platform, easy power scaling is essential when modifying the power system between sedans, minivans, SUVs and other fleet vehicles. Additionally, to achieve full fleet electrification, OEMs need to be able to reuse power designs across different models and platforms to expedite time-to-market.
The flexibility and scalability of our product becomes a key benefit for mainstream OEMs. We are able to propose a module that can be used either with a high-end vehicle by having several in parallel, or a low-end vehicle by using a stand-alone module if the power demand is minimal.
Bodo: The automotive industry is critically sensitive to failures - so what are your zero-defect strategies?
Nicolas: We have many processes and systems in place to ensure that every single module leaving our factory has been tested and fully validated.
This does not start with the day the modules leave our factory but rather much earlier in the module‘s design process. We are using a standard automotive design process from engineering to manufacturing which includes DFMEA and PFMEA. We run a full validation of the module from design validation to process validation – full DV/PV, and we fully characterize boundary limits for each module. Furthermore, our manufacturing operation is working towards TS 16949 qualification which we intend to have fully in place shortly.
We have a dedicated team of engineers striving to make every Vicor automotive product extremely reliable. Furthermore, we have increase our manufacturing floor capacity by 45% to accommodate future growth.
Bodo: Vicor manufactures power modules for demanding markets. Are these DC-DC only?
Nicolas: We target every market that needs DC to DC power conversion. We offer high voltage to high voltage, high voltage to low voltage, isolation, regulation and fixed ratio conversion as required. And all our modules come with the knowledge and expertise needed to build optimized power delivery networks.
Specifically for automotive applications, we work very closely with OEMs to ensure the power converter they use meet their exacting specifications and optimizes their power delivery network.
When customers select a DC/DC converter from Vicor they gain more than the benefits of power efficiency and power density. For instance, the SAC-based BCM power module allows the OEM to remove or virtualize the 48 Volt battery, creating a battery-free 48 Volt network. The virtual battery eliminates the space and weight demands of a real battery, while offering an extremely fast transient response.
There are many valuable benefits to using Vicor technology for DC to DC power conversion. But most importantly, we work with OEMs to customize a solution and ensure unrivalled performance.
Bodo: How are wide bandgap semiconductors contributing to your modules?
Nicolas: Our specific topology and highly optimized architecture let us extract all the potential of regular semiconductors, including high efficiency and power density. We do so by limiting the switching losses using regular silicon-based semiconductors – which are well-proven and easy to obtain.
Although wide bandgap semiconductor prices are dropping there is still significant tension in the supply chain for these components. While we are continuously evaluating the best semiconductor possibilities, including wide bandgap semiconductors for very specific applications, we have noticed that other approaches do not exceed our silicon technology.
We work very closely with semiconductor vendors to optimize each device in terms of all its parameters so we can deliver the best PDN. We want to keep costs low and rely on proven supply chains.
Bodo: I see that Vicor modules can convert between the vehicle’s power train bus voltage and its low voltage circuits – is this correct?
Nicolas: We offer high efficiency conversion to systems engineers and the OEM engineers who design the vehicles’ power delivery networks - we allow conversion from high voltage to low voltage with an extremely wide range. Working from 400 volts, 800 volts or even 1200 volts for some very specific applications, we can efficiently convert down to 48 volts or 12 volts or even lower voltages, for example for autonomous driving.
Some applications demand many hundreds of amps for very power-hungry processors for autonomous driving and Vicor can fulfil this. Vicor excels at converting high voltage down to 48 volts where we also provide an isolation barrier in an extremely compact package, and an optional regulation stage.
We offer a highly flexible, scalable, re-usable modular solutions adaptable to each OEM’s power needs and vehicle platform. We have OEMs that can cover their full range of requirements for all their vehicles - right from low-end through to designer luxury models - by qualifying just three modules. This considerably reduces part number count and qualification effort for OEMs.
We have the BCM6135 which is a 2.5 kilowatt 800 volts to 48 volts isolated fixed ratio converter module in a 61 x 35 millimeter package. This, together with a DCM3735 regulated 2.5 kilowatt 48 Volt to 12 volt module, gives you conversion of 2.5 kilowatt power from high voltage to 12 volts, with isolation and regulation, all in a 35 millimeter by 100 millimeter footprint. You can double this to five kilowatts if your target platform needs more power.
Bodo: We also need an infrastructure to charge electric vehicles. What are Vicor’s plans for the wall boxes required?
Nicolas: The wall box is external to the vehicle and not specifically a target to use automotive-qualified Vicor modules.
However, OEMs need to provide compatibility between their vehicles and the vehicle charging infrastructure. Today, OEMs are developing both 400 volt and 800 volt vehicles. The charging infrastructure has mainly 400 volt charging stations and very few 800 volt stations. So, OEMs designing 800 volt vehicles see foresee range anxiety issues for their customers seeking to charge them on the current network. We have a very unique solution using the NBM9280 which is a fully bi-directional step up/step down SAC fixed ratio module converting between 800 volts and 400 volts. Power capability can reach 150 kilowatts with paralleling.
We also see it as a way to bring compatibility to the 400 volt loads like the PTC heater or air conditioning compressor inside your car. This way, you can have 400 volt loads on the 800 volt system with only an NBM converter between the battery and your load.
Another use is enabling OEMs to use 800 Volt batteries for their high-performance vehicles and 400 volts for the rest of the fleet and still have some systems compatibility.
OEMs get really good utilization out of these bidirectional converters. When the car is driving they are converting 800 volts from the battery to drive the 400 volt loads, and while the car is parked and charging they’re converting the 400 volt intake from the external charging point to charge the 800 volt battery.
Bodo: If we discuss automotive, we think about inverters for the motors. Are you planning to offer products in this segment?
Nicolas: Vicor always strives to innovate and deliver the best-in class power modules. Traction inverter is a large market, and we are investigating it. However, our expertise is focused on DC to DC while inverters require DC to AC conversion technology. We don’t have anything to offer right now, but we continue to investigate and innovate - and if we feel we can bring something valuable to the market in future we will do so.
Bodo: To develop customized solutions, what is the minimum amount required to start an automotive project?
Nicolas: it really depends on the specifics of the solution being sought. We usually work with OEMs to develop customized products that can be reused across many platforms. However, it is also our intention over time to develop a product that could be scaled up in terms of power and voltage to fit not only the original platform but also future requirements.
One investment at the outset can support several years of vehicle development.
For example, an OEM might want to develop a luxury car and later on an SUV which is more powerful. This can be accommodated by reusing a module that has already been developed, but paralleling it to scale up for more power. This means that when an OEM amortizes custom charges out across the whole life of the program the customization costs become nearly negligible.
Also, the OEM needs fewer engineering resources because of the modular approach.
Another big challenge is that OEMs don’t get what they need from Tier One power conversion manufacturers. What we can offer after three or four years’ development with an OEM is not just a particular module but also how to optimize their power delivery network.
One very good example was when an OEM found out that a module was so small that they could package it inside another module so reusing connectors, microcontrollers, and the cooling system and ultimately bringing significant value to the development - it’s one system component less to be qualified for a vehicle platform.
Bodo: Thank you very much Nicolas, for this insightful interview!
Featured image used courtesy of Adobe Stock
This article originally appeared in Bodo’s Power Systems [PDF] magazine.