The Modelling, Design and the Operation of an Electromagnetic Torque Converter

The current hydraulic torque converter has many drawbacks. It requires a significant amount of oil to drive the impeller, and the turbine, which may cause a loss of energy. In addition, the direct contact of the mechanical parts of the conventional hydraulic torque converter increases the possibility of parts failure and mechanical noise. This thesis proposes a new and novel Electromagnetic Torque Converter (EMTC) system, which replaces the conventional hydraulic torque converter. The new EMTC system comprises of two parts, a Differential Machine (DM) part, which is a double rotor single stator machine, and a Variable Frequency Rotary Transformer (VFRT) part, which is responsible for transferring the slip power from between the DM rotors to the DM stator. One of the purposes the VFRT is to eliminate the use of slip rings. In addition, an electronic power converter is used in the EMTC system to convert the frequency of the slip power for re-injection into the DM. Finite Element Modelling (FEM) simulations were primarily used to define the design specifications of an experimental prototype EMTC system. These specifications include the minimum cogging torque, the ripple torque, and the high electromagnetic torque of the DM. FEM simulations were also used to select the stator slot configuration and for predicting the dynamic behaviour of each part of the EMTC system, and a mathematical model was developed. Each part of the EMTC system was characterised experimentally. The complete EMTC system was then tested in both open and closed loop configurations. The FEM simulations and the mathematical model showed good agreement with the experimental results. The new EMTC system resolves many of the drawbacks of the conventional hydraulic torque converter. The outcome of this thesis is expected to provide a step change in electromagnetic converter technology.