Three years ago, Marsilli, a manufacturer of electric motor winding and assembly systems, announced the development of a novel technology called Distributed High-Density (DHD) stator winding. This patented solution is designed to provide a superior alternative to currently available motor winding technologies.
Now Marsilli has announced that the technology is mature. The company is involved in several pilot projects, and is collaborating with partners and customers on new projects to bring DHD to the market.
According to Marsilli, DHD “takes the best features from insertion (pull-in) and hairpin winding technologies,” and is suitable for a wide range of motor sizes, applications and industries, including EV traction motors.
Marsilli’s solution uses thin round enameled copper wire wound in a precisely-layered pattern. This maximizes the slot filling factor, and thus minimizes stator DC copper losses. The use of multiple strands in hand also significantly reduces stator copper AC losses due to the skin effect. DHD winding technology also uses a complete turns transposition, which helps to minimize high-frequency stator copper AC losses due to the proximity effect.
The presence of the pole shoe and the possibility of adjusting the slot opening width as necessary help to reduce torque ripple, which can also deliver a reduction in mechanical vibration. DHD also minimizes the number of wire connections, which requires fewer welding points and enables a cleaner and more reliable process.
DHD-wound prototypes have been manufactured and tested, and their performance has been compared with hairpin motors with similar features. The results showed a comparable efficiency at lower speeds, thanks to the similar copper filling factor, and superior efficiency (up to 6% better) at higher speeds, thanks to DHD’s lower copper AC losses.