In the constant battle between range, weight, torque, and battery size, conventional EV motor design seems to be lagging when it comes to inventiveness. Traditional permanent magnet brushless motors can provide variable speed outputs, with their motors generating high torque at low speeds and high speed at low torque levels. However, the range of speed and torque characteristics may not be sufficient to cover the desired range, even if the output power of the motor is sufficient.
In a conventional motor design, used by all motors to date, there are only two options to address this issue; a more powerful motor could be used to cover the entire range or mechanical gears could be provided for the motor. Both of these methods add weight to the system, which translates to higher costs.
A revolutionary new solution
There is a new solution available to the problems outlined above: ePropelled’s patented Dynamic Torque Switching™ technology, also known as eDTSTM. The “e” in its name represents the technology’s flexible nature. It stands for electric, environmentally friendly, economical, efficient, emerging, etc. It’s a truly versatile solution that evades a simple description.
eDTS is an innovative magnetic gearing technology for electric propulsion systems in which the speed and torque can be varied inside the motor. This patented technology is a drive system concept that allows a single electric machine to dynamically change between several modes to provide a much broader range of high efficiencies for low power consumption. The control system is designed to allow the transition between the modes to take place seamlessly to deliver optimum torque, speed, and efficiency characteristics in real time.
Conventional technology needs to make a compromise between torque and efficiency, which is the main reason for limited range in EVs. In generic terms, this old design has only one mode. ePropelled’s technology provides multiple modes thanks to the switch matrix that connects the sections of the windings in a series, a series of parallel combinations, or all in parallel. Among others, this manages the control of the induced back electromotive force (back EMF), current draw and density, and magnetic flux linkage, resulting in switching the torque, speed range, and constant power range.
More efficient… What does that mean?
Our products deliver a significant improvement in efficiency and a major increase in performance, which translates into reduced costs through smaller battery packs, extended range, or a combination of the two.
But what does “efficient” mean? ePropelled’s take on efficiency is very broad and focused on getting more output from the same input, unlike other technologies. More specifically, we use energy more intelligently and economically to deliver superior performance. Most motors’ highest power efficiency is only available in a very narrow band (a small island, we refer to as a “sweet spot”) on the power map. Our eDTS system allows vehicles to operate at maximum efficiency at a much wider efficiency band (a very large island) on the power map.
Our solution produces a much more energy-efficient method of electric propulsion that increases travel range and life expectancy of the battery pack or allows for smaller batteries for the same range. This is a major improvement to today’s capabilities, and it better meets the expectations of the market, manufacturers, and consumers. eDTS results in:
- at least 15% reduction in system-level energy consumption,
- vehicles lasting longer between charges, and
- lower costs due to smaller batteries and better efficiencies.
The future of electric propulsion
eDTS technology allows the electric motor to provide high torque at low speeds without drawing high current from the batteries. It also provides high speeds at low torque levels without using field weakening, thereby increasing the efficiencies throughout and addressing the problem of high-current and high-torque motors demagnetizing the magnet.
This technique utilizes the motor magnets and the motor windings optimally, and improves the overall drive cycle efficiency, allowing the battery life and the driving range of the vehicle to increase.
Among other benefits, eDTS technology can:
- start the vehicle at low current compared to standard machines, increasing the driving range of the vehicle,
- offer higher starting torque and extended constant power when compared to other machines,
- increase the maximum torque and maximum speed of the motor,
- select the most efficient gear based on vehicle demand, which will save the battery energy and increase driving range, and
- reduce the battery size and cost.
With existing technologies, any improvements to engine efficiency, range, and battery size are minimal and they keep getting smaller. eDTS technology is the big leap the industry needs to diminish costs for manufacturers and provide end users with a better product.
This blog post was adapted from the Dynamic Torque Switching: A Technology Overview, which can be downloaded from this page.
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