A high-performance inverter-fed drive system of an interior permanent magnet synchronous machine

A high-performance, fully operational four-quadrant control scheme for the interior permanent magnet (PM) synchronous machine is described. The machine operates smoothly with full performance in the constant-torque region as well as in the flux-weakening constant-power region in both directions of motion. The transition between the constant-torque region and the constant-power region is very smooth at all conditions of operation. Control in the constant-torque region is based on the vector stator flux, while constant-power region control is implemented through the feedforward vector rotator. The control system is digitally implemented using a distributed microcomputer system, and all of the essential feedback signals such as torque, flux, etc. are estimated with precision. A 70 hp drive system using a neodymium-iron-boron (NeFeB) PM machine and transistor pulse width modulation inverter was designed and extensively tested in the laboratory on a dynamometer, and performance was found to be excellent