Extending capacitor lifetime in a power converter

A control system for a power converter, the control system comprising:

• an observer block configured to estimate a voltage disturbance in an active front end;
• a first control block configured to determine a DC reference current based on a reference voltage for an energy storage apparatus and a measured voltage across the energy storage apparatus;
• a second control block configured to determine a voltage reference based on the determined DC reference current;
• a junction configured to subtract the estimated voltage disturbance from the determined voltage reference to determine a voltage control signal;
• and
• a third control block configured to generate a switch control signal based on the voltage control signal and to provide the switch control signal to an active front end to reduce a ripple current in a rectified current produced by the active front end.

A method comprising:

• estimating positive and negative sequence components of a voltage disturbance in a power converter, the power converter configured to provide a rectified current to an energy storage apparatus;
• determining a voltage control signal based on the estimated voltage disturbance and a reference voltage;
• determining a switch control signal based on the voltage control signal;
• and
• applying the switch control signal to the power converter to thereby reduce a ripple current in the rectified current provided to the energy storage apparatus.