Abstract: Aiming at the technical bottlenecks of the massive sub-module requirement in traditional converters and the dilemma of balancing device reduction and the elimination of large-capacity DC capacitors in existing lightweight topologies (such as AAC), an asymmetric multiplexed bridge-arm leg modular multilevel converter(AMBL-MMC) topology is proposed. Composed of directional switches and cascaded half-bridge sub-modules, this topology adopts a three-phase asymmetric architecture: phases a and c achieve voltage shaping through a half-wave alternating conduction mode, while phase b introduces a time-multiplexed middle arm mechanism to ensure the voltage supporting capability of the system under all operating conditions. The operating principle of the AMBL-MMC is introduced in detail, the power flow models of different bridge arms are derived, and accordingly, the energy balance conditions based on the directional switch conduction angle are constructed. On this basis, bridge-arm energy balance control strategies based on the regulation of the directional switch conduction angle and DC current decoupling are proposed, respectively. Finally, a system simulation model is built in Matlab/Simulink, which verifies the excellent performance of the AMBL-MMC under rated steady-state and dynamic switching conditions over a wide power factor range.