Design and Analysis of Pseudo Direct Drive

Project Title

Design and Analysis of Pseudo Direct Drive

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

Pseudo Direct Drive (PDD), which is a brushless machine that has a simple mechanical structure with the outer Permanent magnets being fixed to the stator, which is equipped with a 3-phase winding. The stator windings interact with the fundamental space harmonic of the flux density created by the Permanent magnets of the inner rotor to produce torque. The high-speed low-torque produced by the interaction is then transmitted as a low-speed high-torque output to the output shaft through the interaction of the stator Permanent magnets with the asynchronous space harmonic created from the modulation by the Pole Pieces with the High Speed rotor Permanent magnets. It has been shown that torque densities of more than 60kNm/m 3 can be achieved with air-cooling at an average current density of less than 2Arms/mm2 for a PDD with a rated torque of ? 100Nm. Furthermore, due to the relatively low operating current densities the achieved efficiencies of a PDD are typically higher than that of electrical machines with similar torque/power ratings.

Project Objectives

The main objective of our project is to replace the conventional electric motor with gearbox into Pseudo direct drive motor. Following are the benefits of doing so:

• Compact Design with high torque density
• Elimination of gearbox
• Low Maintenance and lubrication

Project Implementation Method

Our construction consists of AC induction motor stator from which AC windings is stripped off and 3 phase DC winding is employed connected in a Star connection. Proper magnetic gear parameters will be used which are given in the above table for the construction of rotor. Three phases will be controlled by electronic speed controlled (ESC) and an Arduino for better control system. As rotor position is required by the ESC all the times. So, we will use hall effect sensor to obtain the position of rotor which will then be fed to ESC. We will use a Full Bridge rectifier to convert Ac current to desired DC current.

Benefits of the Project

• Eliminates gearbox
• Very high efficiency (>97%)
• High reliability
• Low maintenance
• Low cooling requirements
• Inherent torque overload protection
• Low NVH
• Large airgaps enable high shock ratings
• Standard power electronic inverter/converter
• Low Cogging Torque (<0.2% of rated torque)
• Significantly smaller and lighter than direct drive equivalents
• High power factor (can be tailored for field weakening applications)
• In-built torsional compliance reduces drivetrain pulsations

Technical Details of Final Deliverable

The PDD combines a magnetic gear with a standard wound stator.  The outer arrays of magnets are fixed to the internal bore of the stator and the magnetic fields generated by the windings are used to drive the internal rotor.  The torque produced by this rotor is then geared up in the magnetic gear and transmitted out via the steel pole pieces.  This results in an extremely compact, highly torque dense machine.  The natural elasticity resulting from the magnetic gear means that the output torque has extremely low levels of ripple (<0.3%)

Final Deliverable of the Project Hardware SystemCore Industry OthersOther Industries Energy , Manufacturing , Transportation Core Technology OthersOther TechnologiesSustainable Development Goals Affordable and Clean Energy, Industry, Innovation and Infrastructure, Sustainable Cities and CommunitiesRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	43800
BLDC Stator	Equipment	1	20000	20000
BLDC Controller	Equipment	1	10000	10000
Neodymium Magnets	Equipment	44	200	8800
Aluminum Cylinder and Acrylic Sheet 1*1 foot	Miscellaneous	1	5000	5000