hyperdrives is an innovative engineering company specialized on electric drive systems.
We develop power-dense, efficient and highly integrated electric drive systems – tailored to your requirements.
Our holistic approach includes both electric motor and inverter. Optimization towards maximum system performance is key.
Our USP? Significant cost reduction.
We offer fully integrated e-drive systems as well as conventional motor plus inverter configurations. The presented drive systems are examples to showcase the capabilities of our team and motor concept.
These systems are no off-the-shelf products – yet.
Highest power-density, especially continuous power output – alongside excellent efficiency over a broad range of the efficiency map are the key characteristics of all our products. Compared to any existing motor topology, our drive systems are more than competitive.
Developing electric motors of insane performance has become an exciting but cost intense competition in the motorsport and aviation industry. 3D-printed coils or cooling geometries, utilizing cobalt-iron, ultra fine laminations, high strength fibers and high fundamental frequencies are the well-known leverage to increase power-density.
Our motors, however, are “standard” from a materials and cost perspective. Outstanding performance is purely derived from the knowhow built-in and unique design decisions made.
Technology
Direct Cooling
The capability of dissipating heat defines the power density of all sorts of energy converters. Liquid cooling of the housing around the motor’s active part has been state of art for more than a century.
Heat flow is limited however. Especially the electrically insulating components wire enamel and slot liner exhibit low thermal conductivity.
The indirect route through the iron laminates causes high differential temperatures between motor winding and cooling fluid.
There are various approaches of getting closer to the source of loss like direct oil spray cooling onto the end windings.
The by far most effective solution are hollow conductors where the cooling fluid has direct contact to the winding.
Thermal simulations have been conducted for both stator segments. Current flow and copper cross section, thus current and loss density are identically. A stator’s typical thermal limits are clearly exceeded for 30 Arms/mm² and conventional indirect cooling.
Direct cooling through hollow conductors in contrast shows massive reserves to further increase load.
The potential to increase current density is truely mindboggling.
Direct cooling comes with new challenges though – high pressure in the hydraulic cooling system, sealing the connection joints, insulation properties of the cooling fluid, manufacturing processes, etc.
The general idea is simple – but the real challenge is greater than just replacing conventional wire by hollow conductor.
We started off from a blank sheet of paper. After extensive research and testing, we are finally there – and proud to offer our unique solution to the puzzle.
Distributed Windings
Innovation is big in the field of electric motors right now.
Competing against the established internal rotor machine, especially axial flux and external rotor motors have drawn a lot of attention. These novel motor topologies claim better efficiency and higher power-density. No doubts, they are competitive.
What do these topologies have in common?
They use concentrated windings.
Concentrated windings are fantastic at first glance. They have short end windings. They are easy to produce and to assemble.
The downside: the magnetomotive force of basically all pole slot combinations creates a vast spectrum of harmonics.
Winding harmonics produce additional losses.
And worst: noise and vibration – a potential killer criteria for many applications and probably a strong reason why these promising machine topologies have not made it in the EV mass market so far.
Distributed windings have a significantly lower pole number in relation to motor speed usually; thus lower fundamental frequencies.
Moderate frequencies allow for standard laminate thickness.
Just as importantly, moderate frequencies will not produce excessive AC losses in the hollow conductors which cannot be produced and interconnected infinitely small.
Stators with distributed windings can be paired with various rotor topologies.
Since we aimed for maximum power density, an IPM reluctance rotor was the number one choice. Squirrel cage rotors for induction machines or separately excited rotors can be appropriate solutions as well, depending on the specifications of each individual application.
Applications
Automotive Industry
excellent part load efficiency
outstanding performance with standard materials
various rotor topologies
competitive performance to cost ratio
designed for mass production
Commercial Vehicles
excellent robustness and durability due to reduced stator temperature level, especially for the winding insulation
high efficiency across the full operation range
machine size optimized for minimal TCO (total cost of ownership)
high constant power density
Aviation Industry
highest power density using standard materials
size optimized for constant flight operation and maximum system efficiency
redundancy through multiphase inverter
low noise and vibration level
Industrial Applications
highest torque and power density
control over motor temperature level
low torque ripple
low noise and vibration level
excellent efficiency across the full operation range
Founders
Benjamin Hengstler
power electronics
motor control
Michael Fick
mechanical design
machine simulation
Concept Proof
It is not about claiming fancy numbers.
It is real.
We have verified all promising simulation data on two evaluation prototypes. The frame surrounding both motors indicates that the original outer dimensions of Ø310mm x 272mm are nearly identical for the reference motor and our evaluation prototype.
We even kept the dimensions of the stator’s bore and joke for fair comparison – same goes for the iron laminate quality.
Merely limited by the test bench, we proved to double the peak power and triple the constant power output of this state-of-the-art PMSM. Efficiency has been improved in all relevant load points.
reference motor
round wire
conventional liquid cooling
PConst. = 70kW
PPeak = 110kW
evaluation prototype
hollow conductor
direct cooling
PConst. = 220kW
PPeak > 220kW
Peak Power Output / Density
2 x
Constant Power Output / Density
3 x
Tech FAQs
1) Claim: It’s better to put more copper in the slot than the “hole” (the cooling channel).
2) You fancy full integration of motor and inverter. What about the conventional arrangement with motor and inverter separated?
Sure. Sometimes the individual packaging of an applicatios preferes this layout.
Our motors are best suited for powerful applications starting from 100kW to several MWs. Where there is power, lots of amps have to be moved between motor and inverter – associated with Ohmic losses, heat and EMF. In terms of efficiency, size, weight and cost, highly integrated systems are the superior choice.
3) Do you only provide 800V-systems as showcased in your data sheets?
No. We just think this is the best option and will be the most commonly choice for powerful drives in the one to several hundreds kW region. We design drive systems for all available voltage ratings.
4) Which power modules do you use for the integrated power electronics?
5) Claim: High pressure and the need for a special pump are disadvantages of direct cooling.
Correct. We eliminated high pressure by design.
Our motors are operated with a standard cooling pump.
6) Which cooling fluid do you use?
This is our little secret.
Sure, we can. If your application requires a short axial motor length or is a direct drive, this might even be the best option. However, concentrated winding machines run on significantly higher fundamental frequencies for the same power output – emphasizing the challenge of increasing AC losses in the winding. Furthermore, concentrated windings have the inherent nature of genrating a vast number of harmonics within the MMF spectrum.
Here is an exemplary comparison between a 18 slot / 16 pole concentrated winding
vs. a 48 slot / 8 pole distributed winding stator.
3-phase MMF, harmonic order
Good point! There is truth in this statement. However, highest efficiency at full load is usually not needed for most applications. Have you ever done drive cycle simulations?
WLTP for instance? It’s all about part load!
Here is a little case study:
Torque is naturally defined as a function of current density and saturation.
Efficiency and power output strongly depend on the motors ability to cool loss power in the first place and how much AC losses increase over speed for all active components.
Let’s compare a single power dense motor (10kW/kg, max. 60A/mm²) to two “standard” motors (5,5kW/kg, 25A/mm²) of roughly double size (and double no-load losses; and double cost).
For the double motor arrangement, efficiency is superior all along the full load curve from zero to maximum speed.