(Electric Machine, Basic Function - GF08.10-P-2000A)
Electric vehicles and hybrid vehicles
Example illustration: hybrid vehicle drive components
Example illustration: electric machine with gearing
Overview
This document contains information on:
- General
- Function
- Asynchronous motors
- Permanently excited synchronous motors
- Electric vehicles
- Hybrid vehicles
General
During engine operation, the electric machine (9) converts the electrical energy into mechanical energy, and thus provides a drive torque. In generator mode, the electric machine (9) converts mechanical energy into electrical energy (recuperation).
Function
The electric machine (9) draws the energy required during engine operation via the high-voltage on-board electrical system from a high-voltage battery (1). The power electronics control unit with integrated power inverter converts the direct voltage from the high-voltage battery (1) into 3-phase alternating voltage to supply the electric machine (9) with power.
The electric machine (9) can be operated as a motor for the drive or as an alternator for recuperation. The rotational speed of the electric machine (9) is recorded by sensors on the electric machine (9).
The changeover between the operating modes engine/alternator operation is controlled by the power electronics control unit. To do this, the three phase currents of the electric machine (9) are regulated depending on the operating mode and the rotor position. These phase currents generate a magnetic rotary field that generates a mechanical torque together with the rotor field.
In engine mode, this leads to a torque that acts directly on the drive and thus powers the vehicle. In generator mode, the electric machine (9) generates a braking torque.
During recuperative braking, electrical energy is generated from mechanical energy. The power supply/recuperation of the energy is implemented via the power inverter integrated in the power electronics control unit.
In the case of vehicles with an electric drive, two different electric machine types are used:
- Asynchronous motors
- Permanently excited synchronous motors
Asynchronous motors
The rotor of the electric machine (14) does not rotate at the same time as the electric rotary field in the stator of the electric machine (12), but asynchronously.
The asynchronous motor, as an electric motor, runs more slowly than the rotary field of the stator of the electric machine (12), but the asynchronous motor, as an alternator, runs more quickly.
In the operating range, the torque is proportional to the deviation of the speed; this is known as "slip".
The stator of the electric machine (12) consists of three coils or a multiple thereof. These are subjected to a three-phase current, which generates a magnetic rotary field.
The rotor of the electric machine (14) that rotates in the stator of the electric machine (12) is designed as a squirrel cage rotor or cage rotor. The rotor conductor rods of the electric machine (14) are shorted with each other at the ends in a ring-shaped arrangement. There is no electrical contact with the outside via brushes.
The rotor of the electric machine (14) is connected directly to the power output shaft via a transmission (16). The electrical connection is made via the power electronics control unit.
Permanently excited synchronous motors
The rotor of the electric machine (14) is made of permanent magnets and rotates synchronously with the rotary field in the stator of the electric machine (12).
In contrast to the asynchronous motor, the rotor of the electric machine (14) is not energized even during operation and therefore generates less heat.
As with the asynchronous motor, the rotor of the electric machine (14) is connected to the power output shaft via a transmission with a permanent transmission ratio (16) without a mechanical separating point. The electrical connection is made via the power electronics control unit.
Electric vehicles
A vehicle can contain one or two electric machines (9). Each of these can be designed as an asynchronous motor with a cage rotor or as a permanently excited synchronous motor.
Hybrid vehicles
The electric machine (9) is designed as a permanently excited synchronous motor. Depending on the model, the electric machine (9) may be located in the drivetrain as follows:
- In automatic transmissions, in the transmission bell housing.
The rotor of the electric machine (14) is positively connected to the engine separator clutch (13) via the rotor carrier.
- Together with the engine separator clutch (13) and the dual clutch (15) in the coupling unit.
The design of the electric machine (9) as a wet runner allows for optimum dissipation of rotor and stator heat loss.
In generator mode, the electric machine (9) generates braking torque that decelerates the vehicle or places a load on the combustion engine (8).
Depending on the model, the transmission of the torque from the electric machine (9) depends on the position of the engine separator clutch (13).
| Additional basic functions | |||
| Rear axle electric drive unit, basic function | Model all with engine 177 with code ME10 (Hybrid vehicle (plug-in, PHEV)) |
GF08.10-P-4000A | |
| Electric machine rotor position sensor, basic function | Hybrid vehicles and electric vehicles with a synchronous machine | GF08.40-P-2002A | |
| Electric machine temperature sensor, basic function | GF08.40-P-2003A | ||
| Electric machine rotational speed sensor, basic function | Electric vehicles with an asynchronous motor | GF08.40-P-2004A | |
| Detailed information | |||
| Electric machine, detailed information | Model 293 with code ME01 (Electric motor) |
GF08.10-P-2500A | |
| Model 167 up to model year 2023 with code ME05 (Hybrid drive 85 kW-94 kW variant (incl. plug-in)) Model 213 as of model year 2021 with code ME05 (Hybrid drive 85 kW-94 kW |
GF08.10-P-2500B | ||
| variant (incl. plug-in)) Model 213 as of model year 2021 with code ME08 (Hybrid drive 75-84 kW VARIANT (INCLUDING PLUGIN)) Model 243 |
GF08.10-P-2500C | ||
| Model 296 | GF08.10-P-2500D | ||
| Component descriptions | |||
| Electrical machine, component description | Model 223 | GF08.10-P-2001A | |
| Model 243 | GF08.10-P-2001B | ||
| Model 206 | GF08.10-P-2001C | ||
| Model 297 | GF08.10-P-2001D | ||
| Model 295 | GF08.10-P-2001E | ||
| Model 232 | GF08.10-P-2001F | ||
| Model 296 | GF08.10-P-2001G | ||
| Model 254 | GF08.10-P-2001H | ||
| Model 214 | GF08.10-P-2001K | ||
| Model 118 as of model year 2023 Model 177, 247 as of model year 2022 |
GF08.10-P-2001L | ||
| Model 167 as of model year 2023 |
GF08.10-P-2001M | ||
| Model 294 | GF08.10-P-2001N | ||
| Model 192 | GF08.10-P-2001R |