There is a problem with the question you asked. "The loss caused by the conversion of mechanical energy into electrical energy" and "the process from kw to KVA" are two concepts.
Let’s look at the process you described first: “Three-phase AC motor” should be a “three-phase AC generator”, otherwise it is impossible to output electrical energy. There is also a problem with the sentence "output 90KVA of electricity". It should be said "the apparent power of the generator is 90KVA".
From the input of the engine to the generator, and then the output of electrical energy from the generator, there is not only mechanical loss, but also electrical energy loss. The engine outputs 96kw of mechanical energy to the coaxial generator. During the operation of the generator, there must be wind resistance and mechanical friction, which will cause part of the loss. This part is mechanical loss; the generator generates electrical energy and outputs it, which is generated in the coil of the generator. Part of the current consumes energy in the resistance of the generator winding, which is called the "copper loss" of the generator. In another part, the current generates a magnetic field on the iron core of the generator, resulting in hysteresis loss and eddy current loss. This part is called "iron loss". Taken together, these two parts belong to electrical energy loss, that is, "mechanical power output by the engine - mechanical loss - electrical energy loss = electrical power output by the generator."
Let’s talk about the difference between KW and KVA. First of all, both are units of power and are the result of voltage × current. However, the meanings expressed by the two are quite different. Regardless of the engine, motor or generator, the output is active power, and the unit of active power is KW. During the power generation process, in addition to generating active electrical energy for output (including losses), the generator can also adjust the generator output The phase relationship between current and voltage outputs reactive power and provides reactive current to the load (mainly used in transformers and motors to establish magnetic fields). Therefore, the electric power output by the generator includes active power (P: unit KW) and reactive power (Q: unit KVar), commonly known as apparent power (S: unit KVA). The relationship between them is: S ?=P?+Q?.
I have written so much, but I don’t know if you have figured it out yet. It’s a pity that I didn’t even get any points.
The energy recovery of electric vehicles is that the vehicle brakes and generates electricity through the motor when decelerating (you can read the junior high school physics textbook for details on how the generator generates electricity), and recycles the electricity into the battery pack. Because traditional fuel vehicles do not have a motor recovery device, the only resistance the vehicle experiences when coasting or braking is the resistance of the entire vehicle (wind resistance, ground friction resistance, etc., brake friction resistance), and the energy generated by deceleration is consumed.
The energy recovery of electric vehicles is that the vehicle brakes and generates electricity through the motor when decelerating (you can read the junior high school physics textbook for details on how the generator generates electricity), and recycles the electricity into the battery pack. Because traditional fuel vehicles do not have a motor recovery device, the only resistance the vehicle experiences when coasting or braking is the resistance of the entire vehicle (wind resistance, ground friction resistance, etc., brake friction resistance), and the energy generated by deceleration is consumed.
3. What are the types of energy recovery for new energy vehicles? What's the difference? What types are there?
There are two main energy recovery modes for electric vehicles: braking recovery and coasting recovery. The difference between the two lies in whether the brake pedal is depressed. As the name suggests, energy recovery is achieved by stepping on the brake pedal, which is called brake recovery. Energy recovery is achieved by coasting by throwing the accelerator, which is called coasting recovery.
There are currently two ways to realize the braking energy recovery of motors, one is the parallel regenerative braking system (RBS), and the other is called the series regenerative braking system (RBS). CRBS).
What is the difference between the two?
RBS Because the brake pedal and the brake wheel cylinder are connected in parallel, during the process of braking and decelerating, the brake wheel cylinder will have hydraulic pressure to brake, and the motor will also generate braking. Therefore, some energy is still lost through braking friction, and the energy recovery rate is low.
The brake pedal and hydraulic mechanism of CRBS are connected in parallel. During the process of braking and decelerating, the motor brakes first, and the motor serves as the main torque source, and the hydraulic brake acts as the brake. Compensation for insufficient power torque.
So CRBS recovers more than RBS, but if the brakes are stepped to a certain depth, the two are almost the same.
Currently, the Xpeng P7 uses Bosch’s Iboost system, which is equipped with a highly efficient CRBS braking energy recovery system. This is one of the reasons why the P7 can achieve an ultra-long battery life of 706 kilometers. (Note: iBooster is an electromechanical servo braking system launched by Bosch in 2013 that does not rely on a vacuum pump. It can achieve energy recovery of up to 0.3g deceleration and increase the cruising range of electric vehicles by up to 20%.)
3. How to choose energy recovery for electric vehicles during actual driving?
Regarding car selection: In order to minimize energy consumption, of course, choose a vehicle with CRBS function. Of course, if you can use coasting energy recovery, use coasting energy recovery more. The reason is that coasting energy recovery is 100% recovery without other external force intervention, and braking energy recovery will consume a certain amount of low-voltage power when CRBS is working. At the same time, under some working conditions There will be hydraulic braking intervention causing energy loss.
(Photo/Text/Photo: Q&A) Wenjie M5 Xpeng Motors P7 AION V Trumpchi GS8 Xpeng P5 Ideal ONE @2019