Synthesis of load-independent AC drive systems

A method is presented of synthesizing load invariant AC synchronous and asynchronous motor drive systems comprising positive stator current feedback of an exactly specified nature and value of its transfer function. The system transfer function independent of load is realized while the stability and dynamics of the system are controlled by an additional voltage loop. For use with an AC drive system, it is shown that load invariance is achieved by closing a positive stator current feedback loop within a negative voltage feedback loop. The transfer function of a feedback network in the current loop is synthesized in an exact relation to the system parameters. The transfer function of the feedback network in the current loop for which the system becomes load independent is given.<>