Modular powertrain goes into series vehicle

March 04, 2016 // By Christoph Hammerschmidt
ZF electric powertrain
The integrated electric powertrain from ZF will enter series production in 2018. With its versatile and modular design, this powertrain will bring forward electrification of large-series vehicles, claims ZF.

The most interesting detail of this announcement keeps in the dark, at least for the time being: Who is the “European automobile manufacturer” that plans to roll out a car with ZF’s electric powertrain inside? As usual in this industry, ZF kept it secretly. The bandwidth of the powertrain leaves ample space for speculation. Designed for motors up to 150 kW, this powertrain can serve a rather broad range of vehicles from compact car to small delivery trucks.

 

In terms of technology, the core element of the powertrain is an asynchronous motor with a two-stage single-speed transmission, differential gear and power electronics and cooling subsystem, all integrated into a compact block. The system can be used as an all-electric drive for battery-operated, fuel cell or hybrid drive vehicles, and it can be placed on the front or rear axle. The drive offers a maximum torque on the axle of 3500 Nm which is quite high, even compared with high-class sports cars. Despite this high power, the system has a weight of just 113 kilograms.

 

Unlike the permanently excited synchronous motor (PSM), the asynchronous motor (ASM) does not require the usage of rare earth metals such as Neodym or Dysprosium. Since the availability and price of these materials on the global market are characterised by strong fluctuations, the elimination of these materials translates into an economic advantage. In addition, the ASM can be operated with more simple rpm sensing and is ideal for short period of high load.

 

The integration of the power electronics circuitry (including controller and software) into the drive package solves a problem that frequently makes the interplay of motor and power electronics difficult; ZF claims that it succeeded in avoiding a large part of the losses in certain driving cycles: By increasing the control voltage, utilising specific modulation schemes, the motor current can be reduced without lowering the performance. Given typical driving cycles, this