Research & Publications 

Publications 

Research Focus 

Machine Design 

Unconventional winding configuration and/or geometries which will operate harmoniously with power electronic converter. It should be mentioned that these projects require not only design and construction of the machine but also the associated power electronic converter and controller. Hence, the challenges are interesting, multifaceted and firmly embedded in the real world. We have also been involved in the simulation, hardware design and control philosophy associated with new converter topologies. 

Design of a novel permanent magnet assisted synchronous motor for traction application

Currently working on. 

Power Electronics 

Especially as applied to variable speed operation of ac machines using different circuit topologies and PWM techniques, in particular, novel AC-AC power converter, matrix converter, and DC-AC power converter topologies. One challenging aspect of research in this area is its multidisciplinary nature. The fundamentals of solid state devices, integrated circuits, control theory, computer simulation, microprocessors, circuit theory and electric machines are all brought into play before a satisfactory design can be realized. 

A novel control for a wound rotor synchronous motor for traction application

Currently working on. 

A novel three transistor voltage source inverter

This topic discloses a novel topology for a voltage source inverter with certain advantages over conventional topologies. In particular, the circuit uses only three high performance transistor switches rather than six switches as in the conventional three leg inverter circuit. Thus, this circuit could prove to be attractive in applications requiring high cost switching components such as new silicon carbide and gallium nitride based devices. In addition to the three switches, two low cost thyristors are used per phase to provide commutation from positive to negative current. Theoretical analysis and simulation results are provided to verify its performance and feasibility. 

A novel six transistor matrix converter

This topic proposes several alternative novel matrix converter topologies based on the structure of a dual bridge matrix converter with certain advantages over the conventional matrix converter topologies. It is demonstrated that, by utilizing 3-transistor inverter at the load side of any indirect matrix converter family could lead to a major reduction in the high performance but expensive transistor count. One matrix converter topology is realized by employing only 12 transistors as opposed to 18 transistors as in the conventional or dual bridge or 15 transistors in the sparse matrix converter. Despite the reduced number of transistors, this topology ensures four-quadrant operation, unity power factor, no dc-link energy storage, and high quality voltage-current waveform. This paper also shows a realization which could reduce the transistor count further to only 6, which fulfills all the desirable features of a matrix converter except that it has unidirectional power flow capability which is still attractive for suitable applications. Thus, these circuits could prove to be attractive in applications requiring high cost switching components such as new silicon carbide or gallium nitride based devices. 

A novel cascaded two transistor H-bridge multilevel voltage source converter

This topic introduces a novel multilevel converter for high power applications requiring expensive switching component such as, traditional Silicon, and/or newly-evolving Silicon Carbide, and/or Gallium Nitride based power semiconductor transistors. This multilevel voltage source inverter consists of several series connected newly developed single phase two transistor H-Bridge inverters with separate DC sources in accordance with the required output voltage level. The topology achieves a major reduction in expensive power semiconductor transistors, which can be accomplished without compromising its performance. For example, the 5-level three phase proposed inverter employs only 12 power transistors as opposed to 24 power transistors of a functionally equivalent conventional cascaded multilevel voltage source inverter.  

Pulsed Width Modulation Control

This topic investigates the realization of several novel converter circuits using several different PWM techniques. Theoretical analyses and simulation results are analyzed to verify the performance and feasibility of the proposed concept.