Patent ID: 8134321

Claim:
A motor control system comprising: an electric motor, a control system coupled to the electric motor and configured to receive a torque command input, a motor speed input, and a voltage input; a plurality of look-up tables, each corresponding to adjacent values of the voltage input, each having an associated maximum torque limit, and each including a two-dimensional array of current commands indexed by values of the motor speed input and the torque command input; wherein the control system is configured to control the electric motor in accordance with the current commands; wherein the control system is configured to determine an applicable operating condition from a set of operating conditions and determine a corresponding desired current command; wherein one of the operating conditions corresponds to a first condition wherein the torque command input is greater than the max torque limit of a first look-up table, but less than the maximum torque limit of a second, adjacent look-up table, and wherein the corresponding desired current command is computed by interpolating between the maximum torque limit of the first table and a revised torque value for the second look-up table; wherein the revised torque value is determined by extrapolating from the maximum torque limit of the first table through a torque value based on the torque command input.