In　practice,　many　factors　result　in　non-equal　cell　DC　voltages　of　the　cascaded　H-bridge　multilevel　(CHBML)　inverter,　such　as　the　differences　amongthe　DC　sources　of　the　H-bridge　cells　and　the　faults　of　the　DC　sources.　The　classical　phase-shifted　carrier　(PSC)　pulse　width　modulation　(PWM)　is　unable　to　eliminate　the　low-frequency　sideband-harmonics　when　the　DC　voltages　of　the　cells　are　not　equal.　The　quality　of　the　output　voltage　degrades.　In　this　paper,　the　relationship　among　the　cell　carrier-phases,　the　DC　voltages,　and　the　harmonics　of　the　output　voltage　are　analyzed.　And　then,　a　novel　PSCPWM　method,　in　which　the　carrier　phases　are　regulated　according　to　the　different　DC　voltages,　is　proposed.　This　method　improves　the　quality　of　the　output　power　by　eliminating　the　low-frequency　sideband　harmonics,　and　also　enhances　the　fault-tolerance　capability　of　the　inverters.　The　simulation　and　experimental　results　obtained　from　the　prototype　of　the　CHBML　inverter　verify　the　suggested　regulation　strategy.　©　2016,　The　editorial　office　of　Transaction　of　China　Electrotechnical　Society.　All　right　reserved.