Is well known in the new energy of pure electric vehicle architecture, the vehicle controller VCU, motor controller MCU and battery management system BMS is the most important core technology, vehicle power, economy, reliability, and security has significant impact, motors, electronic control, battery powered three core piece of the system there are still some technical constraints, the article reports are overwhelming the three core power systems. The only not mentioned is the automatic mechanical transmission system, if it does not exist, only a gearbox, not for the article.

    In the China Society of Automotive Engineering Gear Technology Branch annual meeting, the topic of electric cars automatic transmission caused great enthusiasm delegates, in theory, pure electric vehicles is not required transmissions, only fixed speed ratio reducer. Today, more and more people realize: electric cars need an automatic transmission. Why is that? Domestic electric car manufacturers electric car manufacturing, is no reason why the use of transmission, mainly because people mistakenly believe that electric cars do not need the original transmission. Well, the cost is not worth; domestic automotive automatic transmission is still in the low level of industrialization, the automatic transmission no suitable alternative. Therefore, the "pure electric passenger vehicles technical conditions" does not provide for an automatic transmission, but does not provide a standard energy consumption limits. Only a fixed ratio gear reducer, so that the motor efficiency is often low in the region, not only a waste of precious battery power, but also improves the traction motor, further reducing vehicle driving range. If equipped with an automatic transmission, the motor speed can change the motor operating speed, greatly improve efficiency, save energy and increase driving range, and also increased climbing ability in low gear.

    Transportation and Engineering Sciences Dean Professor Xu Xiangyang Beijing Aerospace University in an interview with reporters, said: "multi-speed automatic transmission, electric vehicles have broad market prospects." Pure electric passenger vehicles large low-speed torque motor, and the motor efficiency is very low, so the electric car start, accelerate and climb steep hills at low power consumption greatly, but also the heating of the motor, the use of electric cars in the foothills of the life, and the town or city where congestion shorten the length of a lot. This need to reduce the heating of the motor with the gearbox, reduce energy consumption, increase mileage and improve vehicle dynamics. To not increase the power, motor power can be reduced further energy saving and improve mileage, streamline the motor cooling system to reduce costs. But the electric car at low speeds or climb steep start, the driver does not feel underpowered and great energy, so pure electric vehicles require automatic gearbox.

    Sina risk passengers Hua-ping 99 mentioned everyone knows is the key to extend the driving range of electric vehicles popular, if the electric car transmission installation, the same battery capacity and extend the driving range of at least 30 percent. This point of view, the author in exchanges with several electric vehicle manufacturers when was confirmed. BYD Qin installed BYD self-developed dual-clutch automatic transmission, driving efficiency is improved significantly. Logically, install electric car transmission is good, but not the manufacturers to install it? The key is not suitable transmission.

    If only the acceleration performance of a motor electric car is enough, if there is a lower gear, with better tires, at the start can achieve much higher acceleration. It is generally believed that if the electric car has a 3-speed gearbox, the performance will be significantly improved, Tesla also said to have considered coupled with such a gearbox. But then, not only increase the cost of increased transmission, but also bring additional efficiency losses, even good dual-clutch gearbox, transmission efficiency can only do more than 90%, but also increase the weight, this will not only reduce power , will increase fuel consumption. So most people do not care to limit performance and increase the gearbox, it did not seem necessary. Car engine configuration is a series with a transmission, electric vehicles in accordance with this idea to do it right? This has not seen success stories, go into the existing car transmission, heavy volume of big expensive, not worth the candle, not only a suitable fixed ratio of the gear unit against use.

    As for the performance in order to accelerate the use of multi-speed, the idea is not so easy to achieve, because the transmission shift time will affect the acceleration performance, the process of shifting dramatically reduce power, a greater shift shock, which vehicle ride and comfort will have a negative impact. Situation look at domestic car will know, creating qualified gearbox harder than create an internal combustion engine. Simplify the mechanical structure of the electric car is the trend, already cut gearbox, added back in order to have sufficient arguments for the job.

    We can not press the phone status of technical ideas do phone hardware and ran multi-core high-frequency direction of development. At the same time the perfect call to mobilize various combinations of the various core various frequency control power, not just a high-performance core with anything.

    In the electric car we should not be separated from the motor and reducer, motor and gear and should, motor controllers together, more of a suit, or a few suits, that more powerful, much stronger performance a. The weight of the energy and the price is not more expensive?

    Analysis, such as BYD E6, motor power 90KW, when divided into two 50 KW, synthesized into a motor drive, the total weight of the motor is similar, the two motors synthesized on a reducer, weighs just have meager increase, although many say the motor controller motor, current control has a lot less.

    In this concept, a concept invented, fuss in the planetary gear, the sun gear connected to a motor A, the outer ring gear up activities connected to another B motors, the two motors can be configured separately to give different the ratio, then the motor controller invokes two motors, there is a premise with brake function without motor. In the planetary gear theory, on the same gear unit installed two motors, respectively, have different ratios, the choice of A motor speed ratio, torque, speed slow. B Motor speed selection faster than small, in the selection of the motor can be free, not involved in two motor speed different from each other, the two motors simultaneously superimposed with speed, torque is the average of the two motor output torque.

    On this principle, the motor can be extended to three or more, according to need to set the number, and if there is a reversal motor (AC induction motor NA), then the output speed is reduced stack, for some very slow while increasing torque Occasion very suitable, especially SUV electric car, sports car.

    Multi-gear automatic transmission applications, starting with two motor analysis, BYD E6, motor power 90KW, when divided into two 50 KW, synthesized into a motor drive, A motor can run 60 K m / H, B motor can be run 90 K m / H, the two motors can be run simultaneously with the 150 K m / H, ① if for a major motor acceleration time by A, up to 40 K m / B plus H when the motor speed. The structure has a characteristic two motors on and off, stop, speed will not be implicated, constraints, when A motor has a certain speed but not enough B motor speed can join in. ② B available to the motor speed at no load. The low speed can be achieved using only a single motor need only high speed and heavy load with only two motors at the same time, reduced from energy consumption, mileage and more.

    In the vehicle design, the voltage setting is an important part of electric vehicle drive motor power is large, the voltage is more than three hundred volts, high voltage insulation performance of the line is high, less secure, production controller high cost, because the higher the pressure the higher the cost of the electronic components. So the speed is not to choose low-voltage, low-speed vehicle that preclude the use of low-voltage, low-speed vehicles can run it? The answer is yes, even a low-speed vehicle, as long as the motor together with a few speed stacking up on high. In the future, we do not have high and low points of the car, only the high and low voltage drive, the configuration of the points.

    Similarly, the hub can also be installed two motors, performance ibid., Spend some more thoughts on design. Electric control aspects as long as a radio and a shared mode, the size of the motor according to the needs of design, mini-cars, commercial vehicles, electric bicycles, electric motorcycles and so is suitable, in particular, electric vehicles, heavy or light loads vary greatly, but more there are stalls automatic transmission.

    Using three or more motors, manufacturing is also very simple, the power to assign appropriate. However, the controller may be more complicated, a radio control with a single, respectively, for the common mode AB, AC, BC, ABC store items, a total of seven, can be understood as a seven-speed, every one of the different ratios. In the use of the most critical is the controller, the controller made simple, trouble driving, but also the system and the vehicle controller VCU and battery management system BMS controller with mutual co-ordination, intelligent control allows the driver to easily control.