Method of monitoring performance of an electric motor

摘要

A method of monitoring performance of an electric motor includes calculating an actual input power and an expected input power of the electric motor. A power difference between the actual input power and the expected input power is recursively calculated over at least one period of an electrical cycle of the electric motor to determine a variance in the power difference during the at least one period of the electrical cycle. The variance in the power difference is compared to a threshold value to determine if the variance in the power difference is greater than the threshold value or less than the threshold value. The control module may signal that the electric motor is not operating within allowable operating parameters when the variance in the power difference is less than the threshold value.

主权项

1. A method of monitoring performance of an electric motor, the method comprising:
sensing an output torque of the electric motor, a temperature of the electric motor, a rotational speed of the electric motor, a voltage of the electric motor and a current of the electric motor, with at least one sensor; communicating the sensed output torque of the electric motor, the sensed temperature of the electric motor, the rotational speed of the electric motor, the voltage of the electric motor and the current of the electric motor, to a control module; calculating an actual input power of the electric motor, with the control module; calculating an expected input power, with the control module; recursively calculating a power difference between the actual input power and the expected input power over at least one period of an electrical cycle of the electric motor, with the control module, to determine a variance in the power difference during the at least one period of the electrical cycle; comparing the variance in the power difference to a threshold value, with the control module, to determine if the variance in the power difference is greater than the threshold value or less than the threshold value; wherein comparing the variance in the power difference to the threshold value includes calculating a state of health percentage of the electric motor; wherein calculating the state of health percentage of the electric motor includes defining a maximum allowable variance of the power difference, and a minimum variance of the power difference; wherein calculating the state of health percentage of the electric motor includes solving the equation:SOH=(Varmax-VarVarmax-Varmin)×100⁢% wherein SOH is equal to the state of health percentage of the electric motor, Varmax is equal to the maximum allowable variance of the power difference, Varmin is equal to the minimum variance of the power difference, and Var is the calculated variance of the power difference of the electric motor; and activating a signaling device to indicate that the electric motor is not operating within allowable operating parameters when the variance in the power difference is less than the threshold value.