Method and apparatus to regulate torque provided to loads

An apparatus for use with a controller providing command voltage signals to control a machine wherein a torque reference value is provided, the apparatus for identifying an error indicative of the difference between the reference torque value and the torque applied to the machine and using the error value to modify control of the machine, the apparatus comprising:

• sensors for obtaining current values corresponding to the currents provided to the machine;
• and
• a processor running software to:
• mathematically combine the current values and feedback voltage values to generate a torque estimate and a flux estimate;
• mathematically combine the torque reference value and the torque estimate to generate a torque error value;
• mathematically combine the torque error value and the flux estimate to generate a corrected flux estimate;
• mathematically combine the corrected flux estimate and the torque reference to produce a current command;
• and
• use the current command value to control the machine.

A method for use with a controller for controlling a machine wherein a torque reference value is provided, the method comprising the steps of:

• obtaining feedback current and voltage values corresponding to the currents and voltages provided to the machine;
• calculating an estimated torque and an estimated flux based on the feedback current and voltage values;
• calculating a torque error as a difference between the torque reference and the estimated torque;
• providing the torque error to a proportional integral control to calculate a gain correction value;
• adding the gain correction value to the estimated flux to provide a corrected flux estimate;
• and
• dividing the torque reference by the corrected flux to generate a current command value for driving the machine.