System and method for reducing delay in the modulation of a multi-phase output voltage from an inverter

A method for generating a three-phase output voltage from a power converter, wherein the power converter executes a plurality of instructions at a periodic interval, the method comprising the steps of:

• during a first switching period:
• measuring a first current feedback value for at least one phase output from the power converter, and
• determining a first voltage reference for each phase of the three-phase output voltage as a function of the first current feedback value;
• during a second switching period:
• measuring a second current feedback value for the at least one phase output from the power converter,
• determining a second voltage reference for each phase of the three-phase output voltage as a function of the second current feedback value,
• generating switching signals for a first phase of the three-phase output voltage as a function of the first voltage reference for the corresponding phase,
• determining an offset value for a second phase and a third phase of the three-phase output voltage, and
• generating switching signals for the second phase and the third phase as a function of the second voltage reference for the corresponding phase and of the offset value.

A motor drive configured to control operation of a multi-phase motor connected to the motor drive, wherein the multi-phase motor has a first number of phases, the motor drive comprising:

• at least one current sensor configured to generate a current feedback signal corresponding to a value of current output from the motor drive;
• and
• a controller configured to execute at a periodic switching frequency to:
• receive the current feedback signal;
• determine a reference voltage for each phase output to the multi-phase motor as a function of the current feedback signal;
• during a first switching period, generate switching signals for a first portion of the phases for the multi-phase motor as a function of the reference voltage determined during a switching period prior to the first switching period, wherein the first portion of phases has a second number of phases, the second number of phases is less than the first number of phases;
• determine an offset value for a second portion of phases for the multi-phase motor, wherein the second portion of phases has a third number of phases, the third number of phases is less than the first number of phases and wherein a sum of the second number of phases and the third number of phases is equal to the first number of phases;
• and
• during the first switching period, generate switching signals for the second portion of the phases for the multi-phase motor as a function of the reference voltage and of the offset value determined during the first switching period.