A method for generating initial operating points for controlling an interior permanent magnet machine, the method comprising: loading an inductance lookup table, the inductance lookup table including sets of a direct axis inductance (L d) value and a quadrature axis inductance (L q) value, each set corresponding to a current peak magnitude and a current control angle, the current control angle indicating amounts of the current peak magnitude appearing as direct axis current (I d) and quadrature axis current (I q); first calculating a maximum torque per Ampere (MTPA) trajectory for a first threshold speed based on machine parameters of the IPM machine, the machine parameters including the inductance lookup table; second, for a first speed higher than the first threshold speed, calculating a voltage limit ellipse for the first speed based on the machine parameters and truncating the voltage limit ellipse to a truncated voltage limit ellipse with monotonically increasing torque; determining an operating trajectory at the first speed based on at least one of the calculated MTPA trajectory and the calculated truncated voltage limit ellipse; wherein the determining step includes: if the first speed is lower than a second threshold speed and higher than the first threshold speed, the determining step determines the operating trajectory based on a comparison of the calculated MTPA trajectory and the calculated truncated voltage limit ellipse; if the first speed is the second threshold speed or higher than the second threshold speed, the determining step determines the operating trajectory based on the calculated truncated voltage limit ellipse with monotonically increasing torque only; and if the first speed is the first threshold speed or lower than the first threshold speed, the determining step determines the operating trajectory based on the calculated MTPA trajectory; generating an I d, I q map that maps an I d value and an I q value to each torque command of a plurality of torque commands for the first speed based on the determined operating trajectory, and using the generated I d,I q map in a machine controller to control the IPM machine. loading an inductance lookup table, the inductance lookup table including sets of a direct axis inductance (L d) value and a quadrature axis inductance (L q) value, each set corresponding to a current peak magnitude and a current control angle, the current control angle indicating amounts of the current peak magnitude appearing as direct axis current (I d) and quadrature axis current (I q); first calculating a maximum torque per Ampere (MTPA) trajectory for a first threshold speed based on machine parameters of the IPM machine, the machine parameters including the inductance lookup table; second, for a first speed higher than the first threshold speed, calculating a voltage limit ellipse for the first speed based on the machine parameters and truncating the voltage limit ellipse to a truncated voltage limit ellipse with monotonically increasing torque; determining an operating trajectory at the first speed based on at least one of the calculated MTPA trajectory and the calculated truncated voltage limit ellipse; wherein the determining step includes: if the first speed is lower than a second threshold speed and higher than the first threshold speed, the determining step determines the operating trajectory based on a comparison of the calculated MTPA trajectory and the calculated truncated voltage limit ellipse; if the first speed is the second threshold speed or higher than the second threshold speed, the determining step determines the operating trajectory based on the calculated truncated voltage limit ellipse with monotonically increasing torque only; and if the first speed is lower than a second threshold speed and higher than the first threshold speed, the determining step determines the operating trajectory based on a comparison of the calculated MTPA trajectory and the calculated truncated voltage limit ellipse; if the first speed is the second threshold speed or higher than the second threshold speed, the determining step determines the operating trajectory based on the calculated truncated voltage limit ellipse with monotonically increasing torque only; and if the first speed is the first threshold speed or lower than the first threshold speed, the determining step determines the operating trajectory based on the calculated MTPA trajectory; generating an I d, I q map that maps an I d value and an I q value to each torque command of a plurality of torque commands for the first speed based on the determined operating trajectory, and using the generated I d,I q map in a machine controller to control the IPM machine.