A flowchart for the steps of advanced drive control development is given in this figure. It is assumed that the machine with the converter and local controller design already exists. In the beginning, the drive control strategy is formulated based on the performance specs of the system. The drive system is then analyzed and control algorithms are developed in detail. However, to have full confidence in the performance of a newly developed controller, it is necessary to perform simulation studies of the whole drive system and modify the control strategy and its parameters as needed. Mathematical models of the converter, machine, and controller are developed and simulation studies are conducted with these models. After the simulation performance is optimized, a prototype drive and its controller hardware and software are designed, built, and tested to finalize the design.