| 主权项 |
1. A method of controlling an output voltage of an inverter of an uninterruptible power supply (UPS) system, the UPS system including an output transformer having a primary side coupled to an output of the inverter and a secondary side coupled to an output of the UPS system, a controller that monitors a primary side voltage and load current flowing through the output of the UPS system, the method comprising:
a. decomposing with the controller the load current into active and reactive components and using them as approximations for IT—active and IT—reactive; b. determining with the controller a voltage drop across the output transformer for a steady state mode of the UPS system (Vreg2) and also for a continuous mode of the UPS system (Vreg1), wherein Vreg1 and Vreg2 are determined by
Vreg1=Gactive*IT—active+Greactive(low)*IT—reactive Vreg2=Gactive*IT—active+Greactive(high)*IT—reactive where Vreg1 is the voltage drop across the output transformer for a continuous mode of the UPS system, Vreg2 is the voltage drop across the output transformer for a steady state mode of the UPS system, Greactive(low) is a gain less than 300, Greactive(high) is a pain greater than 1,000, IT—active is the active component of the load current, and IT—reactive is the reactive component of the load current, and
c. in each of the two modes, determining with the controller a voltage drop across the output transformer (VTVR) to use in determining a desired inverter output voltage of the inverter by
VTVR=Vreg1+ΔVT where VTVR is the voltage drop across the output transformer to use in determining a desired inverter output voltage, ΔVT is zero when the UPS system is not in the steady state mode and ΔVT=Vreg2−Vreg1 when the UPS system is in the steady state mode; and
d. determining with the controller a desired inverter output voltage based on a nominal output voltage of the UPS system and VTVR and controlling an actual inverter output voltage based on the desired inverter output voltage and the monitored primary side voltage. |
