The electric machine is an electromechanical energy conversion device that processes and delivers power to the load. The same electric machine can operate as a motor to convert electrical power to mechanical power or operate as a generator to convert mechanical power to electrical power. The electric machine in conjunction with the power electronic converter and the associated controller makes the motor drive. The power electronic converter is made of solid state devices and handles the flow of bulk power from the source to the motor input terminals. The advances in the power semiconductor technology over the past several decades enabled the development of compact, efficient and reliable DC and AC electric motor drives.
The controller is made of microcontroller or digital signal processor and associated small signal electronics. The function of the controller is to process the user commands and various sensor feedback signals to generate the gate switching signals for the power converter semiconductor switches following a motor control algorithm. The sensor signals include machine rotor position, phase currents, inverter bus voltage, and machine and inverter temperature outputs. Fault protection and diagnostics is also part of the motor controller algorithm.
Research in the area of electric machines and drives is focused on design optimization using 2D and 3D finite element analysis, and drives design at the systems level considering operating requirements and control opportunities. The research is multifaceted seeking innovations in machine configurations, motor control concepts, parameter identifications, and noise and vibration analysis. Motor drives are designed to make the system more efficient, fault tolerant, smoother in operation, smaller and matched to the applications. Modeling and design tools are developed to aid the machine design and drive development efforts. Particular research emphasis is on permanent magnet and reluctance type machines and drives.