Static commissioning method and apparatus to identify rated flux current

A method for use with an adjustable frequency controller to deliver current to a P pole electromagnetic load including a stator and a rotor wherein a rated speed, a rated current value, a rated voltage value, a rated horse power, a leakage inductance value and a stator resistance value are known, the method for identifying a flux current estimate and comprising the steps of:

• (a) mathematically combining the rated horse power and the rated speed to identify a rated torque value;
• (b) providing an initial q-axis current estimate that is less than the rated current value;
• (c) mathematically combining the q-axis current estimate and the rated current value to identify a d-axis current estimate;
• (d) mathematically combining the d-axis current estimate, the q-axis current estimate, the stator resistance value, the leakage inductance value and the rated speed to identify a d-axis current value;
• (e) mathematically combining the d-axis voltage value and the rated voltage value to identify a q-axis voltage value;
• (f) mathematically combining the q-axis voltage value, the stator resistance value, the q-axis current value and the rated speed value to identify a d-axis flux value;
• (g) mathematically combining the pole P number, the d-axis flux value, the q-axis current value, the d-axis current value and the leakage inductance value to identify a torque estimate;
• (h) comparing the rated torque value to the torque estimate;
• (i) where the torque estimate is similar to the rated torque value skipping to step (l);
• (j) reducing the q-axis current estimate;
• (k) repeating steps (c) through (i);
• and
• (l) storing the d-axis and q-axis current estimates as flux and torque current values for subsequent use.

An apparatus for use with an adjustable frequency controller to deliver current to an electromagnetic load including a stator and a rotor, the apparatus for identifying a flux current estimate and comprising:

• a processor running a program for:
• (a) identifying a rated torque value;
• (b) receiving an initial q-axis current estimate;
• (c) using the q-axis current estimate to identify a d-axis current estimate;
• (d) mathematically combining the d-axis current estimate and the q-axis current estimate to identify a torque estimate;
• (e) comparing the rated torque value to the torque estimate;
• (f) where the torque estimate is similar to the rated torque value skipping to step (i);
• (g) altering the q-axis current estimate;
• (h) repeating steps (c) through (f);
• and
• (i) storing the d-axis and q-axis current estimates as flux and torque current values for subsequent use.