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This paper proposes a new inverter topology based on the active neutral-point-clamped (ANPC) converter with capability to integrate one energy storage system (ESS) per inverter leg with an independent state of charge control, so that each inverter leg has two dc ports and one ac port. The primary dc port is common to all inverter legs and it is connected to the main power source. The secondary dc port is suitable for ESS connection because of its two-quadrant operation, with bidirectional current capability, so that the ESS can be charged and discharged with regulated current. Integration of a secondary dc port with independent control also allows the use of different ESS technologies for each inverter leg to compose a hybrid ESS. Redundant switching states of the proposed structure are used to balance the energy exchanged between the secondary dc port and the dc bus capacitors. Theoretical propositions were experimentally validated through a 1-kW single-phase inverter with a secondary dc port connected to a 230-V ESS and ac port connected to an LC filter feeding a linear load. Low total harmonic distortion (THD) sinusoidal current is generated at the ac port while charging or discharging the ESS with a constant current. [ABSTRACT FROM AUTHOR]

This paper proposes a control system for the single-phase Three-Ports Active Neutral- Point-Clamped (ANPC-3P) converter, which can inject a sinusoidal current into the grid, balance the neutral point voltage, and regulate the energy storage system (ESS) current with reduced low-frequency ripple. Despite other applications, ANPC-3P inverter can be used in grid-tied renewable generation to allow the simultaneous connection of a photovoltaic (PV) energy source and an ESS to the AC grid. The ESS is connected directly to the inverter circuit without any auxiliary DC-DC converter, but due to the DC bus pulsed power, it can be subjected to low-frequency current ripple. This undesired current ripple is difficult to filter and can lead to shorter battery life. A control system based on well-known controllers is analyzed and designed. Theoretical analysis is validated experimentally using a single-phase 1-kW prototype. [ABSTRACT FROM AUTHOR]