Electrical machine with fully integrated magnetic gear offering unrivalled torque density

The PDD® machine is a pioneering extension of the low ratio magnetic gear and was invented and demonstrated by Magnomatics personnel in 2005 and is widely regarded as the most significant advancement in electrical machine design for 20 years. This ground breaking technology combines the high torque density of the magnetic gear and the functionality and performance of a brushless permanent magnet machine to offer unparalleled torque output for direct drive applications.

Advantages of PDD®

• Significant size reduction over conventional direct drive machine
• Ultra high efficiency removes the need for ancillary cooling
• Reduced maintenance and improved reliability over mechanically geared drives
• Inherent torque overload protection
• High power factor (typically >0.9)
• Employs standard power electronic controllers
• Possibility for two output shafts with different rotational speeds

Conventional electrical machines can only achieve a relatively low torque output due to the limits on magnetic and electrical stresses that can be used. For compact systems, mechanical gearing is often required to match a high speed/low torque machine to its load, which introduces the need for lubrication, cooling, servicing and the potential for catastrophic failure and jamming on overload.

The PDD® machine is an elegant and extremely compact magnetic and mechanical integration of a low ratio magnetic gear and a brushless permanent magnet motor/generator. This integrated machine has an unparalleled torque density, which is several times greater than a high performance permanent magnet machine, and results in a compact electrical drive that does not require any ancillary lubrication or cooling systems. The ultra high torque dense machine is highly suitable for applications ranging from hybrid vehicle drives to direct drive utility scale wind turbine and marine propulsion systems.

Pseudo-direct drive systems are highly flexible and can be realised in radial-field, axial-field and linear topologies.