Motor control system for determining an operating point for controlling an electric motor

A motor control system for determining an operating point for controlling an electric motor in an electric system having a battery and an electronic control unit, the motor control system comprising:

• a calibrator having an input for receiving a battery voltage (Ubat) of the battery, a motor speed (ωe) and a requested torque (T) of the electric motor, the calibrator calculating a modified speed (ωe*) based on the received battery voltage (Ubat), the motor speed (ωe) and the requested torque (T);
• and
• an operating point controller having an input for receiving a fixed battery voltage reference (Uref), the modified speed (ωe*) and the requested torque (T), the operating point controller determining the operating point for controlling the electric motor based on the received fixed battery voltage reference (Uref), the modified speed (ωe*) and the requested torque (T);
• wherein the control system further comprises a power stage control system connected to the motor control system;
• and
• wherein the power stage control system transforms a voltage (Vd, Vq) request received from the motor control system into duty cycles (a) to command switches of a power stage of the electronic control unit.

A method for determining an operating point for controlling an electric motor in an electric system that includes a battery and an electronic control unit, the method comprising the steps of:

• receiving a battery voltage (Ubat) of the battery, a motor speed (ωe) and a requested torque (T) of the electric motor;
• calculating a modified speed (ωe*) based on the received battery voltage (Ubat), motor speed (ωe) and requested torque (T);
• receiving a fixed battery voltage reference (Uref), the modified speed (ωe*) and a requested torque (T);
• determining the operating point for controlling the electric motor based on the received fixed battery voltage reference (Uref), the modified speed (ωe*) and the requested torque (T);
• and
• comparing the determined operating point to a measured current and outputting a voltage (Vd, Vq) request.

A method for determining an operating point for controlling an electric motor in an electric system that includes a battery and an electronic control unit, the method comprising the steps of:

• receiving a battery voltage (Ubat) of the battery, a motor speed (ωe) and a requested torque (T) of the electric motor;
• calculating a modified speed (ωe*) based on the received battery voltage (Ubat), motor speed (ωe) and requested torque (T);
• receiving a fixed battery voltage reference (Uref), the modified speed (ωe*) and a requested torque (T);
• determining the operating point for controlling the electric motor based on the received fixed battery voltage reference (Uref), the modified speed (ωe) and the requested torque (T);
• and transforming a voltage (Vd, Vq) request into duty cycles (α) and correspondingly commanding switches of a power stage of the electronic control unit.