A device for controlling an inverter, wherein the device is configured for controlling an output of the inverter in an overmodulation region, wherein the inverter includes an inverting module including a plurality of switching elements, wherein the inverting module is configured to receive a direct current, DC, stage voltage and generate an output voltage of three-phases via switching of the switching elements, wherein the device includes: a command voltage outputting unit configured to provide a pulse width modulation, PWM, control signal corresponding to an initial command voltage to the switching elements of the inverting module when the initial command voltage is within a voltage limit; a modulation index modifying unit configured to modify a modulation index of the initial command voltage by referring to a preset modified modulation index table when the initial command voltage is outside the voltage limit; and an overmodulated command voltage generation unit configured to modify the initial command voltage using the modified modulation index to form a modified command voltage and limit the modified command voltage to the voltage limit to generate an overmodulated command voltage, wherein when the initial command voltage is outside the voltage limit, the command voltage outputting unit is configured to inject a PWM control signal corresponding to the overmodulated command voltage to the switching elements of the inverting module, wherein the overmodulation starts when the magnitude of the initial command voltage is V dc 3, wherein the inverter applies a six-step operation and the modulation index has a maximum value of 1, wherein the overmodulation occurs in a region where the modulation index is larger than 0.9067, wherein the device is characterized in that discontinuous command voltages are generated in the overmodulation state, wherein the initial command voltage is modified to six vertices of a hexagon of the voltage limit. wherein the inverter includes an inverting module including a plurality of switching elements, wherein the inverting module is configured to receive a direct current, DC, stage voltage and generate an output voltage of three-phases via switching of the switching elements, wherein the device includes: a command voltage outputting unit configured to provide a pulse width modulation, PWM, control signal corresponding to an initial command voltage to the switching elements of the inverting module when the initial command voltage is within a voltage limit; a modulation index modifying unit configured to modify a modulation index of the initial command voltage by referring to a preset modified modulation index table when the initial command voltage is outside the voltage limit; and an overmodulated command voltage generation unit configured to modify the initial command voltage using the modified modulation index to form a modified command voltage and limit the modified command voltage to the voltage limit to generate an overmodulated command voltage, a command voltage outputting unit configured to provide a pulse width modulation, PWM, control signal corresponding to an initial command voltage to the switching elements of the inverting module when the initial command voltage is within a voltage limit; a modulation index modifying unit configured to modify a modulation index of the initial command voltage by referring to a preset modified modulation index table when the initial command voltage is outside the voltage limit; and an overmodulated command voltage generation unit configured to modify the initial command voltage using the modified modulation index to form a modified command voltage and limit the modified command voltage to the voltage limit to generate an overmodulated command voltage, wherein when the initial command voltage is outside the voltage limit, the command voltage outputting unit is configured to inject a PWM control signal corresponding to the overmodulated command voltage to the switching elements of the inverting module, wherein the overmodulation starts when the magnitude of the initial command voltage is V dc 3, wherein the inverter applies a six-step operation and the modulation index has a maximum value of 1, wherein the overmodulation occurs in a region where the modulation index is larger than 0.9067, wherein the device is characterized in that discontinuous command voltages are generated in the overmodulation state, wherein the initial command voltage is modified to six vertices of a hexagon of the voltage limit.