Zhejiang Founder Motor Co., Ltd., founded in 1995, is a national-level high-tech enterprise specializing in the development, production and sale of drive assemblies, vehicle control systems, motors and motor controllers for energy-saving and new energy vehicles. Since its listing on the Shenzhen Stock Exchange in 2007, Founder Motor has been primarily focused on the rapid development of the global new energy vehicle market. Its product series covers low-speed electric vehicles, light trucks, LV electric vehicles, passenger cars, minibuses, buses, construction vehicles and others. In addition, Founder Motor has carried out in-depth cooperation with several famous auto makers. Founder Motor has always served customers with excellent products and systematic solutions, driving the world and moving forward continuously.
Since the beginning of the 21st century, the Chinese automotive industry has experienced rapid growth. For eight consecutive years from 2009 to 2016, China has been the world’s largest automotive market. In 2016, the annual sales volume of vehicles in China reached 28 million. At the same time, the development of new energy vehicles has made significant progress. In 2016, the total annual sale of new energy vehicles exceeded 500,000 and the cumulative volume exceeded one million.
With this rapid development, the demand for various vehicle-mounted motor systems for the entire industry is growing steadily, including drive motors, seat-regulating motors, glass lifting motors, rear mirror regulating motors, windshield wiper motors, electric power steering systems, braking pressure regulating systems, and others. On the average, each vehicle has more than 20 motors.
With the development of the complete vehicle noise, vibration and harshness (NVH) control technology and the rapid growth of new energy vehicles, the traditional noise sources of vehicles are becoming quieter, making the noises of vehicle-mounted motors more and more prominent. This has become an important factor affecting the comfort indicator of vehicles.
Noises from vehicle-mounted motors are divided into three categories: mechanical noise, wind noise and electromagnetic noise. The main causes of mechanical noise include imbalanced rotors, rolling bearings, friction between carbon brushes and collector rings. The primary causes of wind noise include cooling fans, front and rear claw poles, air flow interferences between fans and end covers and others. Electromagnetic noise is mainly caused by the stator/rotor vibration resulting from electromagnetic force excitation. The frequency of the electromagnetic noise is high, which heavily affects the comfort of drivers and passengers, and draws particular attention from manufacturers of complete vehicles.
For example, consider the new energy vehicle driver motor. Achieving the maximum drive power density usually requires an increase in the electric current harmonics, which will likely result in overlapping between motor tooth space torque and torque pulse, thus increasing the overall electromagnetic noise. The high-frequency noise produced by rotor rotation will directly enter people’s ears. At the same time, stator vibration will pass to the front and rear end covers through the fastening bolts, causing end covers and even the whole vehicle to vibrate, and such vibration will also enter people’s ears through air. Such electromagnetic noise is also frequent and occurs when the vehicle is idling or even driving at low-to-medium speeds.
Complete vehicle manufacturers usually do not pay special attention to motor noises in traditional vehicles, and Founder Motor, as a supplier, seldom considered the noise indicator in their design process. However, with the growing popularity of new energy vehicles, combustion engines, the traditional sources of noises, are replaced, and the problems of vehicle-mounted motors are becoming more and more outstanding. Consumers begin to complain about the loud or abnormal noise of motors at high frequencies or high rotating speeds. This noise has even become one of the main sources of noise and is receiving more attention from manufacturers of complete vehicles. Such attention is also one of Founder Motor’s challenges.
In the past, the upfront stage of the motor design process focused on motor performance only, so when the need for noise control arose at the late stage, manufacturers had limited choices: optimizing electric potential waveform, reducing torque, reducing torque fluctuation, and others. Such regulating plans require many trials and errors, so they are expensive and produce limited results. Without changing the design process, it was impossible for Founder Motor to meet customers’ development requirements in specified time periods.
In order to solve the noise problem of new energy vehicle drive motors, Founder Motor has acted decisively. The company enhanced its own capabilities, including hiring NVH experts, built an anechoic chamber and developed other noise test capabilities.
On the other hand, Founder Motor proactively communicated with its complete vehicle manufacturer customers, to jointly discuss the noise reduction solution starting from the front end of design. Finally, at the recommendation of customers, Founder Motor introduced the LMS Virtual.Lab™ software, of the Simcenter™ portfolio from Siemens PLM Software, using its powerful simulation capability to set up a design optimization and simulation process for noises of vehicle-mounted motors.
In the entire process, Siemens PLM Software provided Founder Motor with exceptional technical support, helping Founder Motor to build a complete acoustic simulation process in only two months, embedding various applications of finite element method and boundary element method into the process, and, at the same time, set up a process for analyzing noise transfer directions and routes based on noise signal features, and finally provided key information for guiding design optimization.
By establishing this process, Founder Motor has significantly improved product quality and is extensively recognized by manufacturers of new energy vehicles.
By establishing this process, Founder Motor has significantly improved product quality and is extensively recognized by manufacturers of new energy vehicles. Zhang Lifeng, NVH technical supervisor at Founder Motor Technical Center, says: “With the help of Siemens PLM Software, Founder Motor quickly set up a motor noise simulation and design process using LMS Virtual.Lab.™ We integrated this process into the motor performance and structural design process, significantly improving product quality and development efficiency. Our joint efforts are also recognized by our customers and help us win a bigger market share.”