Method and System for Early Detection of Abnormalities in Motor Ball Bearings

A motor control system comprising:

• an inverter configured to generate a first phase current, a second phase current, and a third phase current according to an input voltage and control signals;
• a motor coupled to the inverter, configured to drive a cooling fan according to the first phase current, the second phase current, and the third phase current;
• a Clarke Transform block coupled to the inverter, configured to generate a first stator current and a second stator current according to the first phase current and the second phase current through Clarke transformation;
• a Park Transform block coupled to the Clarke Transform block, configured to generate a direct current and a quadrature current according to a rotor angle, the first stator current and the second stator current through Park transformation;
• a position and speed estimator coupled to the Park Transform block, configured to generate a speed signal and the rotor angle according to the direct current and the quadrature current;
• a low-pass filter coupled to the position and speed estimator, configured to generate an average current of the motor according to the quadrature current;
• a first subtractor coupled to the position and speed estimator, configured to generate a first difference signal according to a control speed and the speed signal;
• a first Proportional Integral (PI) controller coupled to the first subtractor, configured to generate a PI signal according to the first difference signal;
• a second subtractor coupled to the first PI controller and the Park Transform block, configured to generate a second difference signal according to the PI signal and the quadrature current;
• a second Proportional Integral (PI) controller coupled to the second subtractor, configured to generate a duty signal according to the second difference signal;
• a space vector pulse width modulation (SVPWM) block coupled to the second PI controller, the position and speed estimator, and the inverter, configured to generate the control signals for the inverter according to the duty signal and the rotor angle;
• wherein:
• the low-pass filter generates a ripple current according to the average current and the quadrature current;
• and
• an alert signal is generated when the ripple current exceed a predetermined deviation threshold.