A motor control system determines an operating point for controlling an electric motor in an electric system that includes a battery and an electronic control unit. The motor control system includes a calibrator having an input for receiving a battery voltage of the battery, a motor speed, and a requested torque of the electric motor. The calibrator calculates a modified speed based on the received battery voltage, motor speed and requested torque. An operating point controller has an input for receiving a fixed battery voltage reference, the modified speed and the requested torque. The operating point controller determines the operating point for controlling the electric motor based on the received fixed battery voltage reference, the modified speed, and the requested torque.