How do electric cars work? BEV, HEV, PHEV in 5 steps

Electric vehicles are those vehicles use one or more electric motors to move from one location to another. Let’s discuss the common question “How do electric cars work?”

Electric cars have a lot of advantages compared to conventional internal combustion engine vehicles. As a result, they are getting popular in the automotive market. Still, they could not capture huge market share in most of the countries. Why is it so?

Most of the vehicle manufactures declared their plan to manufacture electric vehicle in the near future. Is the future of EVs prominent?

What are different types of electric vehicles?

Electric vehicles are classified into three based on how they use energy for propulsion

• Battery Electric Vehicle (BEV)
• Hybrid Electric Vehicle (HEV)
• Plug-in Hybrid Electric Vehicle (PHEV)

Battery Electric Vehicle (BEV) is generally known as Electric Vehicle and it use only electric energy for propulsion. Examples for BEVs are Tesla Model 3, Nissan Leaf etc.

You may check the the list of electric vehicles available in the market

• List of electric vehicles available in the market

Please read comprehensive article about basics of electric vehicle: advantages, challenges, and classifications.

How do electric cars work?

Electric cars use electricity as a source of energy. First of all, let’s see how a battery electric vehicle work. Battery electric vehicle use only electric energy for the propulsion. If you don’t remember what is BEV, HEV, and PHEV, refresh your memory reading basics of the electric vehicle.

Main components of a battery electric vehicle are

• Electric Motor
• Battery
• Power converter
• Battery Management System (BMS)
• A vehicle control unit (VCU)

First three are the basic components required to run a battery electric vehicle. All electric vehicles – Electric scooter, skateboard, electric car, electric train (?) uses them.

An electric train is not an isolated mobile electric vehicle. It”s always connected to the overhead line to get electric energy. So we can leave them out from the group of electric vehicles now.

Okay. Back to the question. How do electric cars work? A detailed explanation of each and every steps of how an electric car work is not presented here. But a quick overview of EVs working principle is presented.

How do Battery Electric Vehicles work?

Working of a BEV can be simplified and explained in below 5 steps

1. The battery of the EV charges from home or charging station
2. The driver presses actuator pedal in the car to accelerate the vehicle
3. Vehicle Control Unit calculates the current and voltage corresponding to the driver’s demand getting feedback from BMS, Motor, and other sensors. Limitation of battery state of charge, thermal limitations, motor torque limitation, and a number of other factors are also taken into account by VCU
4. VCU generates the control signals to the power converter to draw current from the battery
5. Current draws from battery and drives the motor

Space Vector Pulse Width Modulation (SVPWM) inverter is the common AC-DC converter used in an electric vehicle. SVPWM is a bidirectional converter that could charge the battery of vehicle during regenerative braking.

How do Hybrid Electric Cars work?

A hybrid electric vehicle uses electric energy along with one of the other energy sources. An electric motor and IC engine combination is the most common topology used in HEV.

Parallel, series, and parallel/series configurations of HEVs are being manufactured. An HEVs works as below.

1. The driver presses actuator pedal in the car to accelerate the vehicle
2. Vehicle Control Unit calculates the current and voltage corresponding to the drivers demand getting feedback from BMS, Motor, and other sensors. Here the difference comes! A BEV does have an only electric motor but HEV has both an electric motor and IC engine. Requested torque from the driver can be shared among both th IC engine and Electric Motor. Vehicle control unit decides how to split power demand between the electric motor and IC engine. When the vehicle decelerates energy is recuperated and stored in the battery.
3. VCU control motor and IC engine
4. Current draws from battery and drives motor. IC engine also operates consuming fuel

Have you noticed the difference of step 1 in the working of Battery Electric Vehicle and Hybrid Electric Vehicle?

Battery charging of EV is missing for a hybrid electric vehicle! Did I forget to add the point? No. I didn’t. 🙂

A hybrid electric vehicle cannot be charged from the power socket. They don’t have plug-in capability.

Then how does the battery of hybrid electric vehicle get charged? The battery of HEVs charge from the energy generated in an electric machine connected to the IC engine in the vehicle. Along with that battery charges during regenerative braking also.

How do plugin hybrid electric vehicles work?

Plug-in hybrid electric vehicles are capable of getting charged from the power socket and charging stations. And they work almost as similar to a hybrid electric vehicle.