A multi-level medium-voltage inverter (41, 61, 81, 91) that receives three-phase power (42, 62, 82, 92) and outputs a three-phase voltage to a three-phase motor (43, 63, 83, 93), the multi-level medium-voltage inverter comprising: a plurality of unit power cells (45a-f, 65a-c, 85a-i, 95a-o) connected in series to output a single phase voltage, wherein each of the plurality of unit power cells (45a-f, 65a-f, 85a-i, 96a-o) is arranged to output multilevel voltage outputs forming the single phase voltage; and a module-type phase shift transformer (44, 64, 84, 94) configured to convert the three-phase power (42, 62, 82, 92) to apply the converted power to each of the plurality of unit power cells (45a-f, 54a-c, 85a-i, 95a-o), wherein the module-type phase shift transformer (44, 64, 84, 94) includes a plurality of modules, wherein each of the plurality of unit power cells (45a-f, 54a-c, 85a-i, 95a-o) further comprises: a rectifying unit (51, 71) configured to rectify a received output from the module-type phase shift transformer, a smoothing unit (52, 72) configured to smooth the rectified output from the rectifying unit, and an inverter unit (53, 73), wherein the inverter unit (53, 73), configured to have a cascaded T-type Neutral Point Clamped structure, includes a plurality of switch units (53a-f, 73a-f), wherein each switch unit (53a-f, 73a-f) includes a diode and a power semiconductor connected in parallel, wherein pairs of switch units (53c-d, 53g-h or 73c-d, 73g-h) are connected in series with each other and each pair of switch units (53c-d, 53g-h or 73c-d, 73g-h) is connected to associated output ports, respectively, wherein the diode of one switch unit (53c, 53g or 73c, 73d) is conducted to the power semiconductor of another switch unit (53d, 53h or 73d, 73h), when an output pole voltage is zero and an output current is positive, or the power semiconductor of one switch unit (53c, 53g or 73c, 73d) is conducted to the diode of another switch unit (53d, 53h or 73d, 73h), when the output pole voltage is zero and the output current is negative. a plurality of unit power cells (45a-f, 65a-c, 85a-i, 95a-o) connected in series to output a single phase voltage, wherein each of the plurality of unit power cells (45a-f, 65a-f, 85a-i, 96a-o) is arranged to output multilevel voltage outputs forming the single phase voltage; and a module-type phase shift transformer (44, 64, 84, 94) configured to convert the three-phase power (42, 62, 82, 92) to apply the converted power to each of the plurality of unit power cells (45a-f, 54a-c, 85a-i, 95a-o), wherein the module-type phase shift transformer (44, 64, 84, 94) includes a plurality of modules, wherein each of the plurality of unit power cells (45a-f, 54a-c, 85a-i, 95a-o) further comprises: a rectifying unit (51, 71) configured to rectify a received output from the module-type phase shift transformer, a smoothing unit (52, 72) configured to smooth the rectified output from the rectifying unit, and an inverter unit (53, 73), wherein the inverter unit (53, 73), configured to have a cascaded T-type Neutral Point Clamped structure, includes a plurality of switch units (53a-f, 73a-f), wherein each switch unit (53a-f, 73a-f) includes a diode and a power semiconductor connected in parallel, wherein pairs of switch units (53c-d, 53g-h or 73c-d, 73g-h) are connected in series with each other and each pair of switch units (53c-d, 53g-h or 73c-d, 73g-h) is connected to associated output ports, respectively, wherein the diode of one switch unit (53c, 53g or 73c, 73d) is conducted to the power semiconductor of another switch unit (53d, 53h or 73d, 73h), when an output pole voltage is zero and an output current is positive, or the power semiconductor of one switch unit (53c, 53g or 73c, 73d) is conducted to the diode of another switch unit (53d, 53h or 73d, 73h), when the output pole voltage is zero and the output current is negative. a rectifying unit (51, 71) configured to rectify a received output from the module-type phase shift transformer, a smoothing unit (52, 72) configured to smooth the rectified output from the rectifying unit, and an inverter unit (53, 73), wherein the inverter unit (53, 73), configured to have a cascaded T-type Neutral Point Clamped structure, includes a plurality of switch units (53a-f, 73a-f), wherein each switch unit (53a-f, 73a-f) includes a diode and a power semiconductor connected in parallel, wherein pairs of switch units (53c-d, 53g-h or 73c-d, 73g-h) are connected in series with each other and each pair of switch units (53c-d, 53g-h or 73c-d, 73g-h) is connected to associated output ports, respectively, wherein the diode of one switch unit (53c, 53g or 73c, 73d) is conducted to the power semiconductor of another switch unit (53d, 53h or 73d, 73h), when an output pole voltage is zero and an output current is positive, or the power semiconductor of one switch unit (53c, 53g or 73c, 73d) is conducted to the diode of another switch unit (53d, 53h or 73d, 73h), when the output pole voltage is zero and the output current is negative.