It’s a well-known trope that water and electricity don’t mix, but keeping the two separated is often deceptively difficult, because the simple solution of just sealing the box is insufficient on its own. This is because of condensation, which can come from water vapor in the air at the time the box was sealed, or… Read more »
Posts By: Jeffrey Jenkins
A closer look at axial flux motors
In Issue 49, we reviewed some of the more promising advancements in materials and construction techniques for EV traction motors, one of which—the axial flux design—will be the focus of this article. Despite being characterized as an advanced construction technique, the axial flux design is actually one of the oldest ways of constructing a motor—it’s… Read more »
High-voltage EV battery packs: benefits and challenges. More voltage, more better?
In 2020, Porsche delivered just over 20,000 units of its luxury Taycan EV—the first vehicle from a major automaker to sport an 800 V (nominal) battery, which is more than double the voltage of its competitors (and firmly into light-rail and switchyard locomotive territory, actually). It appears that many other EVs will soon follow in… Read more »
Isolation technologies for EV power electronics
A previous article on bidirectional chargers touched on using transformers to provide isolation at high power levels—in which application they are the only game in town, really—but this time the focus will be on achieving isolation at low power levels, such as the feedback signal in a regulator, data communication buses between devices, gate drivers… Read more »
A closer look at the DC Link
The term DC link has traditionally referred to the junction between two power conversion stages where an energy storage element (almost always a capacitor) acts as a buffer for each. A classic example is the capacitor placed between the rectifier and the voltage source inverter in a mains-supplied variable frequency drive (see Fig. 1). This… Read more »
The technical challenges of bidirectional chargers
For years, we’ve been hearing about an EV technology that promises to be a game-changers: Vehicle-to-Grid (V2G) bidirectional charging. My recent work with one V2G charger developer, Fermata Energy, has convinced me that V2G has found its proverbial killer app: load peak shaving for commercial/industrial energy customers. This article is going to concentrate on the… Read more »
Specialized motor materials and constructions (Part 2)
The previous article in this two-part series looked at specialized materials that are (or will be) used in motors; the focus this time will be on the innovative methods of construction that make motors more suitable for EV traction applications. Separating the wheat from the chaff is especially important here, because hyperbole (and outright fantasy)… Read more »
Specialized motor materials and constructions (Part 1)
When demand drives innovation, the state of the art can progress quite rapidly, but if the demand is not there yet, the end result is often the proverbial “solution in search of a problem.” One of the most prominent examples of this is the lithium-ion battery, which was developed in the 1970s, but didn’t really… Read more »
Here’s why Tesla transitioned to a semi-custom power module design in Model 3 inverter
A closer look at semiconductor packaging considerations in EVs One of the most critical decisions to be made at the earliest stage of designing a new power converter concerns the packages used for the semiconductors, as pretty much every other aspect of the design hinges on their physical form. This is especially true for the main… Read more »
EMC for EVs: Understanding electromagnetic compatibility
Engineers who design power electronics supplied by the mains have had to contend with meeting various electrical noise and safety standards for decades now, but their counterparts in the automotive industry were mostly free to do as they pleased. This was mainly because 12 V isn’t considered a shock hazard and cars are effectively rolling… Read more »