Power electronics: the invisible technology that makes electric cars work

What does power electronics do in an electric car? 

 From the charging point to the battery, from the battery to the motor, and all the way to the vehicle’s equipment, electricity flows in different forms and with different characteristics: direct or alternating current, voltage level, output. It has to be constantly converted and adapted to the electric vehicle’s various needs. 

This is where power electronics comes in. It acts as the vehicle’s energy conductor: its job is to send electricity where it is needed, in the right form, at the right time and with as little loss as possible.

Turning electricity into motion 

Contrary to what you might think, the electricity flowing through an electric vehicle is not uniform. Let’s take a closer look: electricity supplied by an alternating current (AC) charging point must first be converted into direct current (DC) by an on-board charger so that it can be stored in the vehicle’s traction battery. Between the battery and the motor, which runs on alternating current, an inverter handles the conversion. When braking, the process is reversed: the energy recovered by the electric motor is converted back by the inverter so that it can be stored in the battery. 

Power electronics comes into play at each of these stages to convert, distribute and control energy flows. Every time you accelerate, every time regenerative braking kicks in, every time you charge, it is working constantly in the background. 

So what does this mean for the driver? By optimising every electricity conversion, power electronics makes better use of the energy stored in the battery. It thus contributes to the vehicle’s range, charging efficiency and energy recovery. 

Energy efficiency: a few percentage points that make all the difference 

Efficiency is one of the key challenges in power electronics. Every time electricity is transformed – for example, when it passes from the battery to the motor and vice versa – some of the energy is lost, mainly as heat. Most of us have noticed that a phone charger can get warm while charging. In an electric vehicle, the power involved is thousands of times greater. 

Improving efficiency by just a few points can therefore have a tangible impact on range and energy consumption. This is where materials chemistry and semiconductor technology come in – semiconductors being components that can let electric current through or block it in a controlled way. For example, using silicon carbide (SiC) semiconductors in an inverter can improve efficiency by almost two points, reducing the inverter’s energy losses. With the same battery capacity, this can add around 10 km of range on a vehicle such as Scenic E-Tech. 

In other words, improving an electric car is not just about increasing its battery capacity. It is also about using the energy already on board as efficiently as possible. 

Power electronics therefore helps make electric vehicles not only more efficient, but also more versatile. It is what now makes it possible to offer new features such as bidirectional charging: energy can not only flow into the battery but also back out to the charging point. A connected vehicle can thus feed electricity back into the grid when needed. This is the principle of Vehicle-to-Grid, or V2G. 

Power electronics: a strategic challenge for the automotive industry 

Beyond the technology itself, power electronics has become a major industrial issue. Converters and the software that controls them are now an essential building block of any electric vehicle. 

For carmakers, the challenge is therefore no longer simply to fit basic electronic units into the vehicle. It is about mastering the technologies that determine their performance, from the choice of power semiconductors to the architecture of the converters and the software that controls them. 

Towards a new generation of electric vehicles 

The story is far from over. 

The next step is to integrate more functions into fewer electronic modules. The aim is to achieve greater efficiency, compactness and simplicity, while reducing system cost and complexity. 

In the future, these architectures will also pave the way for new features, such as optimised fast charging, better battery management in cold weather and improved integration of the vehicle’s various electrical systems. 

Power electronics is one of the technologies that will do the most to make electric vehicles more efficient, more affordable and higher performing. Because the future of electric mobility depends not only on how much energy we can store, but also on how well we use it.