Abstract: The conventional modular multilevel converter（MMC） is difficult to balance the DC fault ride-through capability and the system economy. Aiming at this problem, this paper proposes a T-type alternate arm multilevel converter（AAMC） and its modulation strategy. With the proposed new arm phase-shift modulation strategy, the DC arm of T-AAMC can be constructed by half-bridge sub-modules, which reduces the construction cost and operation losses. Meanwhile, the DC fault ride-through capability is realized by the AC arm constructed with full-bridge submodules in series. First, the topology of T-AAMC are described. The arm phase-shift modulation strategy is determined according to the energy balance condition of each arm, and the operation parameters and hardware configuration of T-AAMC are analyzed. Then, the closed-loop control system is also designed to dynamically balance the energy in AC and DC arms. Furthermore, a comprehensive comparison between T-AAMC and the existing modular multilevel converters is demonstrated. It is shown that, compared with the hybrid MMC, the submodule number,power device number and submodule capacitance of T-AAMC are all reduced. Finally, the proposed topology, the modulation method and the control design are verified by the simulation in the MATLAB/Simulink environment. The proposed T-AAMC can realize the energy conversion with a wide operation range and high efficiency under the normal condition, and it has the DC fault ride-through capability to ensure continuous and reliable operation of the system.