Electric vehicles (EVs) come in various horsepower ranges, and every EV model released is meant to satisfy a particular application. The applications can start from basic utility to sports utility or medium-duty applications. As such, the motor configuration within each EV is different for different applications.
This article discusses the four different motor configurations and understand each configuration’s pros and cons.
Single-motor configuration
As the name suggests, a single-motor configuration employs only one motor to power the wheels of the EV. The motor is responsible for driving either the vehicle’s front or rear wheels. Figure 1 shows the single-motor configuration where the EV battery is connected to the motor, followed by a connection to the differential of the vehicle.
Figure 1. An illustration of a single-motor configuration in an EV. (Image: Rakesh Kumar, Ph.D.)
The advantage of this configuration is its simplicity, as fewer components are used, which makes the system design, manufacturing, and maintenance easy. The smaller number of components also makes the EV cost-effective and lightweight.
This configuration also suffers from disadvantages such as reduced traction as power is delivered to only two wheels. Adding to that, the configuration offers only limited acceleration and top speed compared to multi-motor configurations. This can be challenging while driving in sloppy mountain regions where accelerations are needed during uphill movement.
Nissan Leaf is an example of a single-motor configuration with a front-wheel drive setup. The Volkswagen ID.3 also has the same configuration but with a rear-wheel drive setup.
Dual-motor configuration
A dual-motor configuration is simply two times the single-motor configuration. What it means is that when two single motor configurations are placed back to back, as shown in Figure 2, we obtain a dual-motor configuration. However, the battery is common to both motors. Therefore, this configuration covers both the front-wheel and rear-wheel setup.
Figure 2. An illustration of a dual-motor configuration in an EV. (Image: Rakesh Kumar, Ph.D.)
The benefit of dual-motor configuration is that it has more horsepower than the single-motor configuration. With more horsepower, the vehicle’s acceleration, efficiency, and speed also increase. This configuration offers additional freedom for enhanced traction and stability control than the first configuration.
However, the dual-motor configuration also has the drawback of being more expensive due to additional differential. The extra motor also demands complex control compared to a single motor configuration.
Tesla’s Model S employs a dual-motor configuration with an acceleration of 3.1 s and 670 horsepower. Another EV using this configuration is the Audi e-tron, offering a 484 km range.
Triple-motor configuration
In a triple-motor configuration, one motor is connected to the front-wheel setup while two motors are connected to the rear-wheel setup, as shown in Figure 3. The two motors in the rear wheel are connected to each wheel.
Figure 3. An illustration of a three-motor configuration in an EV. (Image: Rakesh Kumar, Ph.D.)
This configuration is preferred for higher horsepower, better efficiency, and greater speed compared to dual-mode configuration. Better torque vectoring capability is a special feature of triple-motor configuration.
The additional motor adds to the overall vehicle’s weight and makes it bulkier. A dedicated control system needs to be implemented for each of the rear wheels for proper synchronization, thereby increasing the control complexity.
Tesla Model X and Audi e-tron S utilize a triple-motor configuration with one motor for the front wheel and two for the rear wheels. In doing so, the vehicle is able to actively distribute torque to each wheel.
Four-motor configuration
The four-motor configuration has an independent electric motor for each wheel of the vehicle. Figure 4 shows that the common battery supports all four electric motors.
Figure 4. An illustration of a four-motor configuration in an EV. (Image: Rakesh Kumar, Ph.D.)
This configuration supports the highest horsepower among all the four configurations. A dedicated electric motor for each wheel means all-wheel drive stability handling. A special mention is that each motor can individually control the positive and negative torque.
With the highest number of electric motors, it is no surprise that EVs with four-motor configurations are the most expensive. Additional weight and the need for advanced software for a precise control system are other cons of this configuration.
The Rimac Nevera and Rivian R1T have variants that support four-motor configuration. These vehicles are luxury brands meant as a racing car and mini-truck.
Summary
EVs’ four different motor configurations find purposes depending on the desired balance between cost, performance, and complexity. Single-motor and dual-motor configurations are commonly used in affordable mass-market EVs. The triple-motor and four-motor configurations are reserved for high-performance and luxury models. They are also expensive and suitable for specific applications such as a sports utility vehicle and racing cars, to name a few.
References
- Critical Aspects of Electric Motor Drive Controllers and Mitigation of Torque Ripple—Review, IEEE Access
- Types of Motors used in EV | Single, Dual, three & Four Motor Configuration in EV, BeEdu
- What is an electric motor and its configuration? Types of Electric motors in EVs, Prostech
- Single vs dual-motor electric cars: which is best?, Startrescue.co.uk
- Dual Motor vs Single Motor EVs: Which Is Better?, Dubizzle Cars
- Nissan Leaf (first generation), Wikipedia
- Rimac Nevera, Car and Driver
- Motors & Drive Units, EVKX
- EV configurations, LinkedIn
- Volkswagen ID.3, Wikipedia
- Tesla Model X, Wikipedia
- Rivian R1T, Wikipedia
- Audi e-tron S, Audi
- Audi e-tron, Audi
- Model S, Tesla
Images
- Figure 1-4, Rakesh Kumar, Ph.D
Filed Under: Electric Motor, FAQs