<p>Submodule DC voltage unbalancing is the main issue of modular multilevel converter (MMC). To rectify this issue, a modified middleware submodule based modular multilevel converter has been implemented which can reduce the even order ripples in the capacitor voltage at below the fundamental frequency operation. Without the existing additional circuits, a modified circuit is arranged with the help of a diode in the place of the load-connected submodule of the up and down arms of traditional MMC which leads to the reduction of power losses and complexity of the converter. The power may redistribute by the modified circuit from the up arms to down arms when the low operating frequency of output of the converter. Moreover, the common mode voltage is also not imposed on the ac side due to the high frequency modulation. The operation principle, mathematical analysis, and control strategy of the traditional MMC and modified middleware submodule based MMC have been implemented in detail. The modified MMC system has been verified through simulation and hardware-in-the-loop test results.</p>