New 800 volt inverter could provide multiple benefits for electric vehicles

The new Porsche Taycan that was officially and finally unveiled last Thursday is somewhat unique in the electric vehicle arena, kitted out with a 800 volt architecture as compared to the usual 400 volts of other electric cars.

This has been one of the key factors in the German premium carmaker’s demonstration of the Taycan’s ability to maintain performance and endurance as shown in 26 full throttle launches, and its record-setting lap at the demanding Nürburgring Nordschleife.

But that 800 volt architecture is also the reason for the Taycan’s faster charging time. On a 270kW DC charger it can charge its 93kWh battery from 5-80% in just 22.5 minutes, twice as fast as a vehicle with 400 volt architecture.

(On a side note, Porsche originally promised a maximum charging rate of 350kW, but subsequently pulled this back saying its current battery tech cannot yet handle 800 volt, 350kW charging safely.)

A new highly advanced inverter chip from vehicle propulsion tech company Delphi Technologies could see other carmakers follow suit, allowing fast charging as well as other electrical architecture upgrades.

The chip, which is composed of silicon carbide (SiC), is the first to be produced in volume, according to company, and has been designed to enable carmakers to more easily develop 800 volt EVs.

“Doubling the voltage from today’s typical 400 volts brings a substantial range of benefits, both for the vehicle user and for the vehicle manufacturer,” said Delphi Technologies CEO Richard Dauch in a statement.

“We have designed this technology to simplify vehicle manufacturers’ multi-voltage strategies as they extend their electric and hybrid vehicle ranges.”

Inverters can be present in either the vehicle or the charger (in fact, a typical DC electric vehicle charger will contain thousands of these tiny chips), and are a necessity inside the car if a vehicle is to be able to access AC charging.

The new inverter from Delphi uses a specially designed and patented power switch called “Viper” that uses double-sided cooling, resulting in an inverter that is 40% lighter and 30% more compact than inverters typically used by EV makers, says Delphi.

The benefits of this are, per Delphi’s press release, that “vehicle engineers now have additional flexibility to optimize other powertrain systems. Options include more range or a smaller battery; ultra-fast charging or smaller, lighter, cheaper cables; and greater harvesting of vehicle kinetic energy when braking, further extending vehicle range.”

By replacing the traditional silicon used in the Viper power switch with silicon carbide, the inverter can operate at higher temperatures and faster.

“The faster switching alone will allow faster, more compact and lighter motors that offer great efficiency and greater range,” says Dauch. “That’s in addition to the many benefits of moving to 800 volts.”

To produce the 800 volt SiC inverter at volume, Delphi has partnered with silicon carbide semiconductor maker Cree in a deal that will see production of the inverters ramp up in 2022.

“Our collaboration with Cree will create a significant benefit to automakers as they work to balance meeting stricter global emissions regulations with consumer appetite for electric vehicles. Overcoming driver anxiety related to electric vehicle range, charging times and cost will be a boon for the industry,” says Dauch.