Method of controlling dual inverter

A method for controlling first and second inverters having output terminals commonly connected to a motor, the method comprising:

• comparing all voltage commands for driving the motor with the magnitude of a DC voltage commonly applied to the first and second inverters;
• generating a first voltage command with respect to an output of the first inverter and a second voltage command with respect to an output of the second inverter by selectively applying high gain over voltage modulation (HOVM) depending on a result of the comparing, wherein generating the first voltage command and the second voltage command comprises applying HOVM to generate the first voltage command and the second voltage command when the magnitudes of all voltage commands exceed the magnitude of the DC voltage, wherein generating the first voltage command and the second voltage command comprises:
• performing a first shifting to phase-shift all voltage commands by a predetermined angle;
• performing a first conversion to convert all voltage commands phase-shifted through the first shifting into 3-phase phase voltage commands and to convert the 3-phase phase voltage commands into 3-phase terminal voltage commands through space vector pulse width modulation;
• calculating a first gain for application of HOVM based on the magnitudes of all voltage commands phase-shifted through the first shifting and the magnitude of the DC voltage;
• generating the first voltage command by multiplying the 3-phase terminal voltage commands converted through the first conversion by the first gain;
• performing a second shifting to phase-shift all voltage commands in a direction opposite the direction of the predetermined angle;
• performing a second conversion to convert all voltage commands phase-shifted through the second shifting into 3-phase phase voltage commands and to convert the 3-phase phase voltage commands into 3-phase terminal voltage commands through space vector pulse width modulation;
• calculating a second gain for application of HOVM based on the magnitudes of all voltage commands phase-shifted through the second shifting and the magnitude of the DC voltage;
• and
• generating the second voltage command by multiplying the 3-phase terminal voltage commands converted through second conversion by the second gain.

A method for controlling first and second inverters having output terminals commonly connected to a motor, the method comprising:

• comparing all voltage commands for driving the motor with the magnitude of a DC voltage commonly applied to the first and second inverters;
• and
• performing a first conversion to phase-shift all voltage commands by a predetermined angle, to convert the phase-shifted voltage commands into 3-phase phase voltage commands, and to convert the 3-phase phase voltage commands into 3-phase terminal voltage commands through space vector pulse width modulation;
• performing a second conversion to convert the 3-phase terminal voltage commands into d/q-axis voltage commands;
• calculating a gain for application of high gain over voltage modulation (HOVM) based on magnitudes of the d/q-axis voltage commands and the magnitude of the DC voltage;
• performing a third conversion to convert the d/q-axis voltage commands into 3-phase phase voltage commands and to convert the 3-phase phase voltage commands into 3-phase terminal voltage commands through space vector pulse width modulation;
• multiplying the 3-phase terminal voltage commands converted through the third conversion by the gain to generate a first voltage command with respect to an output of the first inverter;
• performing a fourth conversion to convert the first voltage command into a d/q-axis voltage command;
• phase-shifting the d/q-axis voltage command converted through the second conversion in a direction opposite the direction of the predetermined angle;
• converting a value generated by subtracting the d/q-axis voltage command converted through the fourth conversion from the phase-shifted d/q-axis voltage command into a 3-phase phase voltage command;
• and
• converting the 3-phase phase voltage command into a 3-phase terminal voltage command through space vector pulse width modulation to generate a second voltage command with respect to an output of the second inverter.