System and method for controlling an electric motor without a position sensor

A method for controlling an electric motor powered by a DC voltage using a Voltage Source Inverter (VSI), comprising:

• generating a reference voltage vector for the electric motor;
• generating duty cycles based on a DC link voltage to modulate the DC voltage according to the reference voltage vector such that a modulated voltage powering the electric motor reduces an error between a reference value of a state of an operation of the electric motor and a corresponding estimated value of the state of operation of the electric motor;
• estimating a flux error vector based on a difference between a first stator flux linkage observed according to a voltage model based on the reference voltage vector and a second stator flux linkage determined according to a current-flux model of the electric motor;
• estimating a position of a rotor of the electric motor based on a projection of the flux error vector in a direction orthogonal to a direction of a voltage error vector shifted with a phase of dynamics of the hybrid flux observer;
• estimating the value of the state of operation of the electric motor based on the estimated position of the rotor, wherein the dynamics of the hybrid flux observer is represented as an equivalent high-pass filter action on the first stator flux linkage.

A non-transitory computer-readable storage medium embodied thereon a program executable by a processor for performing a method for controlling an electric motor powered by a DC voltage using a Voltage Source Inverter (VSI), the method comprising:

• generating a reference voltage vector for the electric motor;
• generating duty cycles based on a DC link voltage to modulate the DC voltage according to the reference voltage vector such that a modulated voltage powering the electric motor reduces an error between a reference value of a state of an operation of the electric motor and a corresponding estimated value of the state of operation of the electric motor;
• estimating a flux error vector based on a difference between a first stator flux linkage observed according to a voltage model based on the reference voltage vector and a second stator flux linkage determined according to a current-flux model of the electric motor;
• estimating a position of a rotor of the electric motor based on a projection of the flux error vector in a direction orthogonal to a direction of a voltage error vector shifted with a phase of dynamics of the hybrid flux observer;
• and
• estimating the value of the state of operation of the electric motor based on the estimated position of the rotor;
• and
• estimating a DC-link voltage based on a projection of the flux error vector in a direction of the voltage error vector shifted with the phase of dynamics of the hybrid flux observer.