Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
Under the joint action of many factors, electric vehicles have become an unstoppable trend of transportation. There are more and more types of electric vehicles driving on the streets, and consumers’ awareness of electric vehicles has gradually developed from novelty to gradual acceptance. China has been the world’s new energy vehicle production and sales champion for many years in a row.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
But when they really need to choose to buy an electric car, consumers can’t help but start to be confused: Why do most of the luxury electric cars Tesla produced by Americans use something called induction motors, while domestic pure electric cars are basically all What about using a permanent magnet synchronous motor? Is imported stuff necessarily better than our own stuff?
As we all know, the motor is the source of driving force for electric vehicles and is one of the most critical components of its power system. If the engine is the “heart” of a traditional car, then the drive motor is the “heart” of an electric car, and its quality will directly affect the external performance of the vehicle.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
At present, there are two main solutions for electric vehicle drive motors: induction motors (ie AC asynchronous motors) and permanent magnet synchronous motors. Switched reluctance motors are mainly used in the field of new energy commercial vehicles and will not be discussed. The difference between the two can be simply summarized as whether the rotor is synchronized with the stator, and whether it contains permanent magnet materials (NdFeB).
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
The rotor of an induction motor (AC asynchronous motor) always rotates slower than the rotating field of the stator and therefore behaves asynchronously. Due to the existence of slip, the conductor can cut the magnetic induction line in the magnetic field, and at the same time generate an induced current in the conductor, and the name “induction motor” comes from this.
Induction motors are characterized by a relatively simpler structure, lower cost, and greater power, but they have disadvantages such as larger size and heavier weight. Representative models include Tesla’s Model S/X and Weilai ES8.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
The permanent magnet synchronous motor is very similar to the AC asynchronous motor in structure. The main components are also the stator and the rotor. The structure of the stator is the same as that of the AC asynchronous motor, but the rotor is composed of a permanent magnet.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
The speed of the permanent magnet synchronous motor rotor must be equal to the synchronous speed of the stator, and the rotor is a permanent magnet with strong magnetic field, and the magnetic field will not disappear, so it is called “permanent magnet synchronous motor”.
Compared with induction motors, permanent magnet synchronous motors have the advantages of high power density, high energy conversion efficiency (about 90%-95%), and low energy consumption. At this stage, more than 90% of electric vehicles use AC asynchronous motors or permanent magnet synchronous motors, because permanent magnet synchronous motors are smaller in size and higher in efficiency under the same power, and are more likely to be favored by more car companies. Although permanent magnets have the risk of demagnetization at high temperatures, some car companies have overcome this problem. For example, BYD has improved the anti-demagnetization ability of permanent magnet synchronous motors by optimizing the direct axis inductance and salient pole ratio.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
In addition, the NdFeB permanent magnet materials required by permanent magnet synchronous motors need to use rare earth resources. For countries that lack rare earth resources or have underdeveloped rare earth industries, the technical solution for vehicle power motors is related to national security. my country has 70% of the world’s rare earth resources, and the total output of NdFeB magnetic materials has reached 80% of the world’s total.
In 2017, my country’s annual installed capacity of vehicle motors reached 874,000 units, of which permanent magnet synchronous motors accounted for 77%, with a total installed capacity of 680,000 units. From January to August in 2018, 551,000 automotive motors have been installed, and the proportion of permanent magnet synchronous motors has risen to 78.33%. In terms of the supporting supply of permanent magnet synchronous motors, BYD has taken the top position in the installed capacity of motors for vehicles (including passenger cars and commercial vehicles) for four consecutive years since 2015, followed by BAIC New Energy, Shanghai Electric Drive, and Jingjin Electric And other well-known domestic enterprises. However, if the electric vehicles of European and American car companies want to use permanent magnet synchronous motors, they have to consider the issue of importing rare earth materials or motor assemblies.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
I believe that after seeing this, you will understand why Tesla Model S/X has always insisted on using induction motors. Moreover, Tesla has switched to a permanent magnet synchronous motor on the new model Model 3, and its energy efficiency is significantly better than that of the previous two generations of models. Tesla Model 3 accelerates from 100 kilometers to 3.5 seconds (performance version), and the top speed exceeds 200km/h. Domestic BYD’s new generation Tang EV600 also uses a permanent magnet synchronous motor, which enables a medium and large SUV to accelerate to 100 kilometers in 4.4 seconds, and the maximum speed has also reached 180 km/h.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
For domestic new energy car companies, BYD is currently the only OEM that has completely independently developed and designed permanent magnet synchronous motors. Many people know that BYD started with batteries, and its power battery system is very good, but few people know that BYD’s motor-related technologies are not inferior. BYD motors and motor control systems are produced and developed by the 14th Division, covering a variety of family products with different powers, which are fully applied to its new energy passenger cars, electric buses and new energy special vehicles.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
As of 2018, BYD’s passenger car drive motors have six models with a maximum output power of 70kw, 110kw, 120kw, 150kw, 160kw and 180kw. Among them, the drive motor with a maximum output power of 120kw has been adapted to the Qin Pro EV500 model, and the drive motor with a maximum output power of 180kw will be used in the upcoming Tang EV 600 model, and in addition to the single motor version, there will also be The electric four-wheel drive Tang EV model with dual 180kw motors was launched.
The coils of BYD permanent magnet synchronous motors are excited by permanent magnets instead of coils. In this way, the power consumption of the excitation coil is saved, the electromechanical conversion efficiency of the motor is improved, the driving current can be reduced, and the cruising range can be extended. In addition, BYD is also a domestic new energy company that has always insisted on using high-power motors. The maximum speed of the new generation of motors has reached the 15,000 speed range, and it also has a very wide economic speed to further reduce energy consumption.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
Taking Qin Pro EV500 as an example, it is equipped with a new “3-in-1” electric drive technology. Adapted to the permanent magnet synchronous motor integrated with BYD’s latest generation technology, its maximum power is 120kw, maximum torque is 280N m, and the motor speed is as high as 14,000rpm. The main parameters such as power and torque are fully upgraded.
With the support of the new technology, Qin Pro EV500’s 0-50km/h acceleration time is only 3.7 seconds, the measured 0-100km/h acceleration time is 8.2 seconds, and the 60km/h constant-speed pure electric cruising range is 500 kilometers; it has liquid cooling The nickel-cobalt lithium manganese oxide (ternary lithium) battery assembly with high-temperature heat dissipation and low-temperature preheating functions has an energy density of 160.9Wh/kg and a carrying capacity of 56.4 kWh.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
Along with improved performance, the new generation of motor technology can also lead to better economic performance. The maximum speed of this permanent magnet synchronous motor is 15000 rpm. This means that the maximum speed of the vehicle is higher, and the comprehensive power consumption in the 60-120 km/h speed range is smaller, which can directly increase the cruising range of long-distance high-speed driving.
With the help of the integration of BYD’s “3-in-1” electric drive technology, it can not only improve efficiency and reduce weight, but also reduce size and facilitate the modularization of different vehicle platforms. The cost of electric drive technology is reduced by 33%, the volume is reduced by 30%, the weight is reduced by 25%, the torque density is increased by 17%, the power density is increased by 20%, and the NEDC efficiency index is increased by 1%.
Why is the permanent magnet synchronous motor with high integration, high power and low energy consumption the right choice
The accumulation of core advantages in the three-electric system has made BYD’s performance in the domestic new energy vehicle market unmatched. On January 7, BYD Auto announced its sales report for December 2018. In December last year, BYD sold a total of 46,700 new energy vehicles, a month-on-month increase of 55.11%, and the company’s cumulative sales of new energy vehicles in 2018 also reached 247,800. In the sales of passenger vehicles, the sales of pure electric vehicles and plug-in hybrid vehicles were 103,300 and 123,900 respectively. The sales of the above two businesses have become “evenly matched”.
In addition to sales, the announcement also mentioned that BYD’s total installed capacity of new energy vehicle power batteries and energy storage batteries in 2018 was about 13.373GWh. At the same time, BYD’s new energy vehicle industry chain covers the upper, middle and lower reaches, and at the same time masters battery, motor electronic control, charging infrastructure and vehicle technology. It is expected that in 2019, with the help of a new generation of products, the sales of BYD’s new energy passenger vehicles will continue to increase, stabilizing its leading position in new energy vehicles.