March 10, 2019 by Sam Holland
With so many countries recognising the danger of climate change and the environmental stewardship needed to counteract its effects, electric vehicles are seen as a green alternative that is both environmentally friendly and practical.
While the market for electric vehicles steadily grows, there are also major breakthroughs being made in the area of self-driving vehicles. Both electric and autonomous vehicles depend heavily on state-of-the-art components and systems: components that many large automakers have begun to invest heavily in.
Image courtesy of Pixabay.
Electric vehicles (EVs) depend on an electric motor for propulsion and batteries for powering that motor. There are three categories of key components for EVs: the electric motor, the power source, the controllers for power, and the motor itself. For the purposes of this article, we are going to focus on battery electric vehicles (BEVs).
Obviously, an electric vehicle is going to have an electric motor; however, there are many different types of electric motors and not all are appropriate for use in BEVs. That being said, the most commonly used electric motors are brushless DC (BLDC) motors, but both AC motors and brushed DC motors are also used. BLDCs are popular because of their fast motor response, the simplicity involved in keeping them cool, and their excellent efficiency.
The primary source of power driving electric motors for consumer vehicles is most typically either rechargeable batteries or an electric generator powered by a fuel source, such as fuel cells. These batteries are used not only to propel the vehicle but to also power all its electronic systems.
Image courtesy of Pixabay.
The most common type of battery is rechargeable lithium-ion batteries (LIBs), which are popular because they have excellent power and energy density (which is key when designing compact cars) combined with a good lifespan. Another battery option said to be in development is solid-state batteries. Other options for batteries include nickel-metal hydride and lead-acid batteries.
Power management, as the name implies, primarily performs management and measurement directly related to power control, including thermal dissipation and overall power consumption. The motor controller’s key job is to distribute battery power to the various systems in the vehicle, while also regulating and monitoring performance indicators and efficiency.
A self-driving vehicle, also known as an autonomous vehicle, is able to manoeuvre without requiring human control or interaction.
Of course, the technology behind these vehicles is highly intricate: it requires a wide variety of sensors and controls in order to function properly. Three of the key components found in self-driving vehicles can be categorised as the computer vision system, the positioning system, and the processors that enable all the operations to work together.
Without a vision system, self-driving vehicles would be extremely dangerous. On a self-driving vehicle, the primary component in the vision system is not a digital camera, as you may expect, but a LIDAR system.
LIDAR, which stands for Light Detection and Ranging, combines light and radar to provide a robust 3D representation of the area around the vehicle. An array of timed cameras may also be used in conjunction with LIDAR to achieve an even more accurate 3D representation. For close positioning tasks such as parking, side and bumper-mounted radar are often used.
GPS is responsible for navigation, guidance, and geographic positioning. Many of these GPS systems are implemented using a system on a chip (SoC) technology, or multi-chips. GPA antennas are usually a small wound stub design or a ceramic chip unit. Note that antennas with right-hand circular polarisation characteristics (RHCP) are required to match the polarisation of the GPS signals.
To aid with navigation and positioning when GPS signals are blocked, smart cars also have inertial measurement units (IMUs). IMUs combine three gyroscopes and three accelerometers to measure relative position, including both linear and rotational motion. The gyroscopes and accelerometers themselves are MEMs devices.
Image courtesy of Pixabay.
Some autonomous vehicles have 20 different processors that handle everything from artificial intelligence, image processing, steering, braking, and speed control. When the amount of real-time data from the vision system alone is accounted for, the processing power required for an autonomous car to operate is extensive.
If the research and investments made by major automobile manufacturers are any indications, then EVs and smart cars are going to appear prominently in our future. Technology such as BLDC motors, fuel cells, LIDAR, and powerful processors are destined to become far more commonplace when it comes to daily transportation, and we can only dream of the technology that will someday replace them.
For more information on EVs, why not check out another article on Electronics Point: The Biggest Complaints Related to Buying EVs.
