Definition of electric motor drive system

According to the vehicle power battery state and the whole vehicle power demand, convert the electrical energy output from the vehicle energy storage or power generation device into mechanical energy.

And through the transmission device to transfer the energy is to the drive wheel. In the vehicle braking part of the vehicle, mechanical energy is into electrical energy back to the energy storage device.

Motor drive system classification  

The electric drive systems are divided into the following three categories: pure electric vehicles, hybrid electric trams, and plug-in hybrid trams.

1. Pure electric vehicles can be divided into four categories according to different motors: single motor drive system, dual motor drive system, hub motor drive system and wheel side motor drive system.

Working principle of single-motor drive system

Features: The electric motor replaces the engine, keeping the original transmission and mechanical drive unchanged.

Advantages: simple structure, low technology, a small modification of the whole vehicle, high reliability and low cost.

Working principle of dual-motor drive system

Features: Dual side motors drive independently, eliminating the gearbox, mechanical drive shaft, and differential.

Advantages: Simple structure, the flexible connection of power by cable, flexible arrangement, effective use of space.

Wheel motor drive system working principle

Advantages: Hub motor has the advantages of high efficiency, energy saving, lightweight and miniaturization, the ultimate solution for electric vehicles.

The wheel hub motor integrates power, transmission and brake into the wheel hub, changing the central drive into distributed drive, eliminating transmission, drive shaft and differential, reducing 80% of transmission parts and 30% of its weight.

Wheel side motor drive system

Features: Dual side motors are driven independently, the motors are on the outside of the hub, and the motors drive the wheels through reducers.

Advantages: simple structure, effective use of wheel-side space, suitable for heavy-duty, high-torque vehicles. 2.

2. Hybrid electric vehicles can be divided into series, parallel and hybrid vehicles according to the arrangement.

Tandem hybrid vehicles

Features: mechanical and electric power flow in series, pure electric drive wheels, increased braking energy recovery function.

Advantages: simple power flow, easy energy management, energy saving.

Disadvantages: Uncompact system, low technology. Has been eliminated.

Parallel Hybrid

Parallel type has low technical content and insignificant advantages. It is also gradually being eliminated.

Hybrid Hybrid

Currently commonly used form, for 4 × 4 wheel hybrid, the advantages are obvious.

Advantages: give full play to the advantages of high efficiency of mechanical transmission, compact structure, commonly used working conditions using mechanical transmission; mechanical drive and motor drive at the same time, as long as a drive mode works properly, the vehicle can run; suitable for multi-wheel drive vehicles, near the front part of the traditional mechanical transmission, the vehicle is less modified.

Disadvantages: the increase of generator and generator controller, occupying space and increasing costs; the need to match the electrical power balance, increasing the complexity of energy management; complex structure, high engineering requirements.

3. Plug-in hybrid power system

According to different configuration forms can be divided into series, parallel and hybrid plug-in hybrid power system.

Hybrid: motor participation in driving the maximum of about 10% called weak hybrid, accounting for more than 30% called strong hybrid.

Plug-in hybrid: pure electric drive range is more than 50km.

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