Agile uninterruptible power supply for efficient critical load support and grid contingency ride-through

An uninterruptible power supply system comprising:

• a source side converter (SSC) coupled to an AC source and configured to provide autonomous grid support including reactive power support during fault conditions;
• a load side converter (LSC) coupled to a critical load and configured to support the critical load by boosting voltage at load terminals through autonomous injection of reactive current;
• a DC energy storage coupled to the SSC and the LSC;
• a bypass connection between the AC source and the critical load, the bypass connection including a ride-through inductor with measurement capability;
• one or more sensors configured to measure electrical parameters associated with the bypass connection;
• and
• a controller configured to:
• (i) operate the SSC and the LSC during nominal source conditions to minimize power flow through the SSC and the LSC and transfer a majority of load power through the bypass connection;
• (ii) compensate for critical load variations using either the SSC or LSC or both based on bypass connection measurements;
• (iii) operate the LSC during abnormal source conditions to inject reactive power to the critical load through the ride-through inductor and to maintain stable voltage and frequency without requiring opening of the bypass connection;
• and
• (iv) maintain terminal AC voltage of the LSC synchronized with AC source voltage to enable seamless bypass breaker reclosure after fault clearance.