Wheel hub motor: redefining the integrated revolution of electric vehicle drive

Wheel hub motor is an innovative driving technology that highly integrates power, transmission, and braking systems inside the wheels. It completely eliminates the mechanical transmission path of traditional vehicles and greatly simplifies the overall structure of electric vehicles. By independently arranging motors on each wheel, hub motors achieve flexible and efficient distributed driving, bringing breakthrough changes to automotive design and performance.

1、 Historical evolution: Century of technological accumulation and revival
Wheel hub motors are not an emerging concept. As early as 1896, Ferdinand Porsche obtained a patent for wheel hub motors; In 1900, the first electric vehicle equipped with a wheel hub motor was introduced. In the 1970s, this technology was applied to special vehicles such as mining transport vehicles.

In the field of passenger cars, Japanese car companies laid out research and development earlier, and international giants such as General Motors and Toyota continue to invest resources to promote the practical application of wheel hub motors from a technical concept.

2、 Background of hub foundation and motor integration
Wheel hub (also known as wheel rim) is a key component that supports the tire and is installed on the axle. At the beginning of the 20th century, casting technology achieved the integration of wheels, hubs, and spokes, and aluminum alloy materials subsequently replaced steel, achieving lightweight and diversified shapes.

The wheel hub motor is built into the drive system based on this foundation, combining structural support and power output functions, becoming the core of the new generation of electric drive systems.

3、 Technical advantage: Simplify structure, improve efficiency
The most significant advantage of wheel hub motors is their greatly simplified vehicle structure. Eliminating components such as clutches, transmissions, driveshafts, differentials, etc. not only reduces weight and costs, but also improves reliability and space utilization.

Its distributed driving feature supports flexible configuration of front wheel drive, rear wheel drive, or four-wheel drive modes. By independently controlling the left and right wheel speeds, differential steering can even be achieved, significantly reducing the turning radius and improving maneuverability.

4、 Classification and mainstream technology routes
Wheel hub motors can be classified into multiple dimensions such as motor type, structural form, and driving mode:

Motor types: mainly including permanent magnet motor (PM), asynchronous motor (IM), switched reluctance motor (SRM), and transverse flux motor (TFM). Permanent magnet motors are the most widely used, while transverse flux motors have attracted much attention due to their suitability for low-speed and high torque scenarios.

Structural form: divided into radial magnetic field, axial magnetic field, and transverse flux motor; According to the movement mode, there are internal rotors, external rotors, and dual rotor structures. The dual rotors achieve speed superposition through planetary gears and have good disturbance resistance and load adaptability.

Driving mode:

Direct drive: often using external rotors, with simple structure and low noise

Indirect drive: achieving high speed and high power density through a deceleration mechanism

At present, external rotor direct drive has become the mainstream choice due to its high reliability, wide speed range, and large output torque.

5、 Key Control Technologies
Wheel hub motors often use brushless motor technology, and their control core lies in rotor position identification and torque optimization:

Position detection: In addition to sensor solutions, sensorless technology estimates rotor position through methods such as back electromotive force and inductance;

Torque pulsation suppression: For torque fluctuations caused by electromagnetic, commutation, and cogging factors, optimization design, current feedback, and skewed pole method can be used to suppress them;

Weak magnetic expansion speed: By using control strategies above the base speed, the speed range can be expanded. Currently, constant power weak magnetic speed regulation can reach 2.8 times the base speed;

Speed regulation methods mainly include PWM modulation, frequency modulation, and current limiting control.

6、 Application prospects: The ultimate driving form of electric vehicles
Under the dual pressure of energy and environmental protection, electric vehicles have become a strategic focus of the global automotive industry. As a third-generation electric drive technology, wheel hub motors have the advantages of being more efficient, lightweight, and energy-saving compared to central motors and wheel edge motors, and are considered the ideal driving solution for pure electric vehicles.

It not only omits a large number of transmission components, achieving power transmission braking integration, but also endows the vehicle with unprecedented layout freedom and handling potential. With the continuous breakthroughs in battery technology, electronic control systems, and energy management technology, wheel hub motors are expected to gradually move from special vehicles to the mainstream passenger car market.

The industry consensus is that wheel hub motors will completely transform the form of vehicle driving, just like touchscreens replacing keyboards. Although there are still challenges in terms of cost, suspension load, and reliability, with the maturity of technology and the emergence of economies of scale, it may become a standard configuration for the next generation of electric vehicles, redefining people's travel experience.