System and method for unified common mode voltage injection

A power conversion system, comprising:

• at least one multi-level power converter;
• a controller coupled to the at least one multi-level power converter, the controller comprising:
• a first common mode voltage (CMV) injection module for generating a first CMV signal for modifying at least one voltage command to achieve a first function in association with operation of the power conversion system;
• a second CMV injection module for generating a second CMV signal based at least in part on a three-level CMV limit for further modifying the at least one modified voltage command to achieve a second function in association with operation of the power conversion system;
• wherein the second CMV injection module comprises:
• a min-max classifier for determining an instantaneous maximum voltage, an instantaneous medium voltage and an instantaneous minimum voltage from three- phase AC voltage command signals;
• a CMV limit calculator for calculating a maximum CMV limit and a minimum CMV limit based on instantaneous maximum voltage, the instantaneous medium voltage, the instantaneous minimum voltage and the three-level CMV limit;
• wherein modifying the at least one voltage command includes adding the first CMV signal into the at least one voltage command;
• and wherein the first CMV signal is generated based at least in part on the instantaneous maximum voltage and the instantaneous minimum voltage.