Optimizing the building blocks for megawatt chargers

The Megawatt Charging System (MCS) standard supports up to 3.75 MW (1250 V and 3000 A) and ruggedized MCS or R-MCS can even go up to 6 MW (1500 V and 4000 A) from a single dispenser. Current developments from key industry players are already enabling charging at an electrical capacity as high as 3.75 MW—enough to recharge a long-haul truck in under an hour.

Some of the largest warehouse stores in the US such as Costco have a peak demand of about 1 MW and take up about 3.3 acres of land. That means: one 6 MW R-MCS chargers could use six times the power of a Costco Warehouse or the equivalent of a warehouse building covering 20 acres.

Now imagine a typical distribution centre with 50 loading docks for trucks. If half of the bays had a dedicated 1 MW MCS charger, you would need the 25 MW electrical capacity equivalent to 25 large warehouses…

Clearly, it’s impractical to just add more power. It’s also about doing it smarter. So how do we address this challenge?

1. Know your real load

Not all vehicles need full power at the same time. Even if all cars were charging at the same time, batteries have charging curves that slow down near full.

In reality, not all chargers are in use at all times. Additionally, some vehicles are left plugged in after they are done charging. Rather than planning for the maximum theoretical power that could be used if every charger was delivering full power simultaneously, it’s smarter and more realistic to size the electrical infrastructure based on the highest likely power demand over a 1-hour window—also known as the 1-hour peak load.

2. Be smart about your power electronics

Instead of dedicating full power hardware to every dispenser, use a bank of intelligent power electronics that can re-route that power on demand. This helps reduce installation costs and avoid stranded assets. This centralised power cabinet strategy is already commonly placed at many Tesla Supercharger sites.

These distributed DC charging networks also need the ability to control how much power each vehicle receives as well as provide fault protection against a common DC link. A single fault shouldn’t be able to cause critical safety issues. To prevent this risk, we need to add galvanic isolation between each battery system and the DC link, so that electrical problems in one part don’t affect or harm the others—either the user or the equipment.

The MCS standard is pushing for higher DC Voltage in order to hit the maximum power levels, but also to reduce cable sizing. Smaller cables are easier for the operator to plug in and keep the vehicle lighter and more cost-effective. Simply put, cable sizing is determined by how hot it gets when current flows through it. By increasing the system voltage from 1000 V to 1500 V, you can deliver the same amount of power with less current, cutting heat generation by about 55%. That means thinner, lighter, and easier-to-handle cables, which also reduce overall system costs.

While most power converters in the market offer up to 1000 V max, ADVANTICS goes the extra mile with its advanced power converters with a wider voltage range up to 1500 V—converting high-power MCS into a reality.

Fleet operators have a business to run and shouldn’t be concerned about the reliability of their equipment. However, chargers installed in harsh environments frequently see salt fog, high humidity, or peak temperatures. Many air-cooled chargers work just fine in the lab, but have failed in the field due to contamination and corrosion. Especially in marine environments, air-cooled modules are impractical due to the corrosive nature of saltwater and high humidity. Air cooling may offer cheaper up-front costs—but you ultimately pay for it with equipment downtime and expensive field service repairs. We want to make it easy (in reality, less stressful) for you to implement the use of renewable energy like electric powering in harsh environments.

To avoid these contamination issues and increase reliability, power modules should be fully sealed. By liquid cooling these power modules, they can have precise temperature control and avoid some of the thermal cycling that tends to occur on components even with sealed air cooling. Thermal cycling is one of the major contributing factors to component stress, leading to field failures. Understanding these customer needs, ADVANTICS has engineered a series of power modules specifically to address the heavy-duty MCS market segment. These power modules are infinitely scalable, so even if you wanted 25 MW of fast charging for your 25-stall MCS charging depot, we can help you do that.

The pairing of ADVANTICS AC/DC rectifiers (ADB-PC-AC01) and 100kW isolated 1500V DC/DC (ADB-PC-DC01) converters is ready for the growing needs of the MCS market. We are here to help you tackle this next wave of heavy-duty fleet megawatt charging.

In our next edition of Current Affairs, we will go the opposite wave of the current, as we share with you our origin story, where you will discover how a passion for power conversion and EV technology, hacking a Tesla motor and strong determination, led ADVANTICS to grow from the garage to the grid.

See you next month!