Arm Phase-Shift Conducting Modulation for Alternate Arm Multilevel Converter With Half-Bridge Submodules

In this article, the arm phase-shift conducting modulation (PSCM) is proposed for the alternate arm multilevel converter (AAMC). With the PSCM strategy, the half-bridge (HB) structure could be applied as the submodule (SM) topology to reduce the circuit complexity of the full-bridge submodule based AAMC. First, the phase-shift angle is introduced to match the voltage modulation ratio and power factor of ac grid. The energy stored in the submodule capacitors are balanced by regulating the phase-shift angle. Then, the design criteria and operation performance for HBSM-AAMC with the proposed PSCM strategy are analyzed and presented. Compared with HBSM-modular multilevel converters (MMC), 18% HBSMs and 9% power devices are reduced with the proposed topology and modulation, resulting in the lower construction cost. Furthermore, the loss distribution is analyzed, and the operating losses of HBSM-AAMC are smaller than that of HBSM-MMC. Finally, the simulation and experiment are performed to verify the effectiveness of the derived topology and the proposed modulation strategy.

Automated summary

This article introduces an arm phase-shift conducting modulation strategy to improve the efficiency and reduce the cost of alternate arm multilevel converters. By introducing a phase-shift angle and using the half-bridge structure as the submodule topology, the energy stored in submodule capacitors can be effectively balanced and circuit complexity reduced. Simulation and experimental results validate the effectiveness of this modulation strategy.