Patent ID: 8031495

Claim:
A step wave power converter comprising: multiple different bridge circuits configured to convert DC voltage inputs into AC voltage outputs; and a processor configured to: estimate an average voltage output from the multiple different bridge circuits for controlling current output from the multiple different bridge circuits; identifying how many of the bridge circuits are needed to provide the estimated average output voltage; and controlling the identified bridge circuits during the next switching period to generate a combined inverter output voltage that corresponds with the estimated average output voltage, wherein the average output voltage is estimated according to: V op ⁢ ⁢ _ ⁢ ⁢ av ⁡ [ n ] = 1.5 ⁢ ⁢ V grid ⁡ [ n ] - 0.5 ⁢ ⁢ V grid ⁡ [ n - 1 ] + L · I ref ⁡ [ n + 1 ] - I load ⁡ [ n ] T period where: T period is a switching period [n,n+1], V op — av [n] is the average voltage output over the switching period [n,n+1], V grid — av [n] is an average grid voltage over the switching period [n,n+1], I load [n] is a measured load current at a sampling point of [n], I ref [n+1] is a reference current at a sampling point of [n+1], and L is a filter inductance.