Disclosed herein is a method for controlling an electrical converter system that includes: determining a nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) and a reference trajectory (x*) of at least one electrical quantity of the electrical converter system over a horizon of future sampling instants, the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) comprises switching transitions (Δu.sub.p,i*) between output voltages of an electrical converter of the electrical converter system and the reference trajectory (x*) indicates a desired future development of an electrical quantity of the converter system; determining a small-signal pulse pattern (ũ.sub.abc(t, λ.sub.p,i)) by minimizing a cost function; determining a modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) by moving the switching transitions of the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) to generate modified switching transitions; and applying at least the next switching transition of the modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) to the electrical converter system.

Disclosed herein is a method for controlling an electrical converter system that includes: determining a nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) and a reference trajectory (x*) of at least one electrical quantity of the electrical converter system over a horizon of future sampling instants, the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) comprises switching transitions (Δu.sub.p,i*) between output voltages of an electrical converter of the electrical converter system and the reference trajectory (x*) indicates a desired future development of an electrical quantity of the converter system; determining a small-signal pulse pattern (ũ.sub.abc(t, λ.sub.p,i)) by minimizing a cost function; determining a modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) by moving the switching transitions of the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) to generate modified switching transitions; and applying at least the next switching transition of the modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) to the electrical converter system.

A motor control method for controlling a motor by using an applied AC voltage converted from a DC voltage with an inverter driven by a PWM control, the motor control method includes: calculating a voltage command value for the inverter in order to achieve a desired torque output in the motor; calculating a compensation gain configured to maintain a linear relation between the voltage command value and the applied AC voltage according to a modulation factor indicating a ratio of the applied AC voltage to the DC voltage before and after a conversion in the inverter; limiting the compensation gain using an upper limit value; calculating a compensation voltage command value by multiplying the voltage command value by the limited compensation gain; and applying the applied AC voltage to the motor by driving the inverter using the compensation voltage command value; wherein the upper limit value is set so that the upper limit value become smaller when the modulation factor changes significantly.

A motor control method for controlling a motor by using an applied AC voltage converted from a DC voltage with an inverter driven by a PWM control, the motor control method includes: calculating a voltage command value for the inverter in order to achieve a desired torque output in the motor; calculating a compensation gain configured to maintain a linear relation between the voltage command value and the applied AC voltage according to a modulation factor indicating a ratio of the applied AC voltage to the DC voltage before and after a conversion in the inverter; limiting the compensation gain using an upper limit value; calculating a compensation voltage command value by multiplying the voltage command value by the limited compensation gain; and applying the applied AC voltage to the motor by driving the inverter using the compensation voltage command value; wherein the upper limit value is set so that the upper limit value become smaller when the modulation factor changes significantly.

A motor can be controlled in a user-friendly manner so that a phase current based on an input command torque command value is caused to flow to at least one among U-phase, V-phase, and W-phase windings of the motor, so that a predetermined in-phase current is superimposed on the phase current and caused to flow to at least one among the windings. The motor is controlled such that energization to one winding corresponding to a predetermined energization stop phase is stopped, for example, so that energization to the U-phase winding is stopped, and so that a V-phase current, a W-phase current and an in-phase current are caused to flow to each winding corresponding to a phase other than the energization stop phase, for example, so that the V-phase current, the W-phase current and the in-phase current are caused to flow to the V-phase winding and the W-phase winding.

A motor can be controlled in a user-friendly manner so that a phase current based on an input command torque command value is caused to flow to at least one among U-phase, V-phase, and W-phase windings of the motor, so that a predetermined in-phase current is superimposed on the phase current and caused to flow to at least one among the windings. The motor is controlled such that energization to one winding corresponding to a predetermined energization stop phase is stopped, for example, so that energization to the U-phase winding is stopped, and so that a V-phase current, a W-phase current and an in-phase current are caused to flow to each winding corresponding to a phase other than the energization stop phase, for example, so that the V-phase current, the W-phase current and the in-phase current are caused to flow to the V-phase winding and the W-phase winding.

A current sensor state determination device determines that an abnormality is caused in a current sensor when a sum of phase currents based on current detection values from each of the current sensors in three phases is greater than a first determination value, and determines that no abnormality is caused in the current sensor when the sum of phase currents is equal to or less than the first determination value. The state determination device determines that the current sensor is normal when it is determined that (i) no abnormality is caused in a preset electric angle range equal to or less than one electric-angle cycle of the rotating electric machine and (ii) a value of an electric current flowing in the rotating electric machine in a rotating coordinates system calculated based on the current detection value is equal to or greater than a second determination value.

A current sensor state determination device determines that an abnormality is caused in a current sensor when a sum of phase currents based on current detection values from each of the current sensors in three phases is greater than a first determination value, and determines that no abnormality is caused in the current sensor when the sum of phase currents is equal to or less than the first determination value. The state determination device determines that the current sensor is normal when it is determined that (i) no abnormality is caused in a preset electric angle range equal to or less than one electric-angle cycle of the rotating electric machine and (ii) a value of an electric current flowing in the rotating electric machine in a rotating coordinates system calculated based on the current detection value is equal to or greater than a second determination value.

A diagnostic system includes: a current command module configured to, based on a motor torque request, a motor speed, a direct current (DC) bus voltage, generate a d-axis current command for an electric motor and a q-axis current command for the electric motor; a voltage command module configured to, based on the d-axis current command and the q-axis current command, generate a d-axis voltage command and a q-axis voltage command; a switching control module configured to control switching of an inverter module based on the d-axis voltage command and the q-axis voltage command, where the inverter module is configured to apply power to stator windings of the electric motor from the DC bus; and a fault module configured to selectively indicate that the stator windings of the electric motor are degraded when the d-axis voltage command is less than a predetermined nominal d-axis voltage of the electric motor.

A diagnostic system includes: a current command module configured to, based on a motor torque request, a motor speed, a direct current (DC) bus voltage, generate a d-axis current command for an electric motor and a q-axis current command for the electric motor; a voltage command module configured to, based on the d-axis current command and the q-axis current command, generate a d-axis voltage command and a q-axis voltage command; a switching control module configured to control switching of an inverter module based on the d-axis voltage command and the q-axis voltage command, where the inverter module is configured to apply power to stator windings of the electric motor from the DC bus; and a fault module configured to selectively indicate that the stator windings of the electric motor are degraded when the d-axis voltage command is less than a predetermined nominal d-axis voltage of the electric motor.