Shanghai Jiaotong University

Weixin Fang

Gang Shi

Xu Cai

Jianqiao Zhou

Jianwen Zhang

Han Wang

Yixin Zhang

Jiacheng Wang

Disclosed is a solid-state transformer having an uninterrupted operation ability under an AC/DC fault, in which bridge arms of a hybrid modular multilevel converter include half-bridge submodules and full-bridge submodules. The half-bridge submodules and the full-bridge submodules are connected with input ends of isolated dual-active-bridge converters via DC capacitors of the half-bridge submodules and full-bridge submodules; output ends of the isolated dual-active-bridge converters are connected in parallel to form a low-voltage DC bus; and a three-phase full-bridge inverter is connected to the low-voltage DC bus. The solid-state transformer may be provided with four ports including a medium-voltage AC port, a medium-voltage DC port, a low-voltage DC port and a low-voltage AC port which are beneficial to the interconnection of multi-voltage-level and multi-form AC/DC hybrid distribution grids. The solid-state transformer has the uninterrupted operation ability under the AC/DC fault.

Solid-state transformer having uninterrupted operation ability under AC/DC fault and control method thereof

A modular multilevel converter with multi-port DC power flow control includes a modular multilevel converter topology and a DC power flow controller, wherein an input terminal of the DC power flow controller is connected in series to uppermost submodules of upper arms of the modular multilevel converter topology, and with power transfer and energy interaction between the modular multilevel converter topology and an AC power grid, a converter station or a solid state transformer based on the modular multilevel converter topology has a function of direct current power flow control. The output terminal of the DC power flow controller adopts DC/DC converters to regulate the output voltage, and a plurality of DC/DC converters share a common DC bus with the ports connected with different DC outlet lines, thereby providing a plurality of flexible and controllable DC ports.

Modular multilevel converter with multi-port DC power flow control and control method thereof

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Shanghai, China

Weixin Fang