System and method for power conversion

A grid-side transformerless power conversion system configured to perform power conversion between a power grid and a load, the power conversion system comprising:

• a first converter configured to convert first AC power provided from the power grid into DC power, the first converter comprising:
• a first converter module;
• and
• a second converter module coupled to the first converter module to form a nested neutral point piloted topology;
• a differential-mode (DM) filter coupled between the power grid and the first converter;
• a second converter coupled to the first converter, the second converter configured to convert the DC power into second AC power and provide the second AC power to the load;
• and
• a common-mode (CM) filter coupled between the power grid and the first converter or coupled between the first converter and the second converter.

A method for performing power conversion between a power grid and a load using a power conversion system, wherein the power conversion system comprises an AC-DC converter and a DC-AC converter, wherein the AC-DC converter comprises at least a first converter module and a second converter module coupled together to form a nested neutral point piloted topology, the method comprising:

• receiving first AC voltage filtered by a grid-side filter, wherein the first AC voltage is not processed by a grid-side transformer;
• converting the first AC voltage to DC voltage using the AC-DC converter;
• converting the DC voltage to second AC voltage using the DC-AC converter;
• and
• providing the second AC voltage to the load.