Three Phase PR Controller Design

I am developing a UPS that must feed unbalanced three-phase loads, and I need a proportional-resonant (PR) controller designed specifically for this purpose. The controller’s sole mandatory feature is automatic voltage regulation; overcurrent protection and fault detection can be left out for now.
. Your task is to work out the control strategy, select suitable PR gains, and show—simulation in simulink —that the scheme can track a sinusoidal reference with negligible steady-state error under unbalanced loading.

Deliverables
• Control-loop design rationale and equations
• Recommended PR gain values (and tuning method so I can adapt them)
• A reference implementation (MATLAB/Simulink model, demonstrating steady-state voltage regulation under an illustrative unbalance case
• Brief report summarising results and practical implementation notes

I will test the design on my UPS bench; if it maintains balanced phase voltages within ±2 % under at least 30 % load asymmetry, the job is complete.
Only expert power Electronics with control expert with simulink should bid.