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Utility scale photovoltaic plants often use megawatt scale central inverters with high efficiency and power density. Inverter manufacturers now offer solutions over 2 MW for 1000 V DC class PV arrays. Certifying inverters at this power level can present test equipment design and procurement challenges. This paper describes a retrofit of an existing medium voltage, 9-level TECO Westinghouse VersaBridge series connected H-bridge (SCHB) inverter to supply DC power up to 2500 A at 1000 V for central inverter testing. Simulations in PLECS and controller hardware-in-the-Ioop experiments with RTDS were used for initial controller design. The SCHB pulse width modulation scheme led to an interleaved output stage topology in a six parallel module configuration without requiring modification to the existing VersaBridge controller.Commissioning results are shown along with experimental results for the first inverter test article at 2500 A, 900 V.

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