A controllable rectification device, comprising: an inverter which comprises three switch element groups (Q1, Q2, Q3) connected in parallel, each switch element group (Q1, Q2, Q3) comprising at least two switch elements (IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, IGBT6) connected in parallel, each switch element (IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, IGBT6) comprising an upper bridge-arm switch (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') and a lower bridge-arm switch (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6"); a control panel for generating a PWM waveform; and characterized by a drive panel for generating a plurality of drive voltages PWMn', with n being an integer ranging from 1 to 6, according to the inputted PWM waveform to drive the upper bridge-arm switch (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') and a plurality of drive voltages PWMn" according to the inputted PWM waveform to drive the lower bridge-arm switch (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6") so that the upper bridge-arm switch (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') and the lower bridge-arm switch (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6") of each switch element (IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, IGBT6) conduct or break separately, the upper bridge-arm switches (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') in the same switch element group (Q1, Q2, Q3) conduct or break synchronously and the lower bridge-arm switches (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6") of the same switch element group (Q1, Q2, Q3) conduct or break synchronously, wherein drive voltages PWMn' and PWM(n+1)', where n may be 1, 3 or 5, are synchronous, and the drive voltages PWMn" and PWM(n+1)", where n may be 1, 3 or 5, are synchronous. an inverter which comprises three switch element groups (Q1, Q2, Q3) connected in parallel, each switch element group (Q1, Q2, Q3) comprising at least two switch elements (IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, IGBT6) connected in parallel, each switch element (IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, IGBT6) comprising an upper bridge-arm switch (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') and a lower bridge-arm switch (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6"); a control panel for generating a PWM waveform; and characterized by a drive panel for generating a plurality of drive voltages PWMn', with n being an integer ranging from 1 to 6, according to the inputted PWM waveform to drive the upper bridge-arm switch (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') and a plurality of drive voltages PWMn" according to the inputted PWM waveform to drive the lower bridge-arm switch (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6") so that the upper bridge-arm switch (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') and the lower bridge-arm switch (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6") of each switch element (IGBT1, IGBT2, IGBT3, IGBT4, IGBT5, IGBT6) conduct or break separately, the upper bridge-arm switches (IGBT1', IGBT2', IGBT3', IGBT4', IGBT5', IGBT6') in the same switch element group (Q1, Q2, Q3) conduct or break synchronously and the lower bridge-arm switches (IGBT1", IGBT2", IGBT3", IGBT4", IGBT5", IGBT6") of the same switch element group (Q1, Q2, Q3) conduct or break synchronously, wherein drive voltages PWMn' and PWM(n+1)', where n may be 1, 3 or 5, are synchronous, and the drive voltages PWMn" and PWM(n+1)", where n may be 1, 3 or 5, are synchronous.