Abstract: With the increasing proportion of photovoltaic power generation in the power structure, the demand for affordable grid-connected photovoltaic power generation is becoming increasingly urgent. Using 1500 V photovoltaic module can effectively reduce the cost and loss of cable in photovoltaic power plant, which is very important for the early realization of the connection to grid at an equal price. For the application of 1500V string inverters, the voltage stress of traditional two-level and T-type three-level topology’s switching devices increases substantially, which makes the efficiency and power density difficult to optimize. With a lower voltage stress, active neutral-point clamped five-level（ANPC-5L） inverter is much suitable for technical requirements of 1500V photovoltaic system. To further improve the power density of inverters, this paper proposed an interleaved active neutral-point clamped nine-level topology and its modulation and control strategy, by rational designing its coupled inductor, the circulating current of the topology was also suppressed. Finally, experimental results obtained with an experimental prototype were presented to verify the effectiveness of the proposed topology, modulation and control strategy.