A rotary current machine system and method for controlling an electric rotary current machine, in particular an induction machine, having a rotor, a stator and at least two phase windings is disclosed. At least one electrical signal, in particular a voltage signal, is applied to at least one phase winding, preferably all phase windings, of the rotary current machine, and the current waveform in the at least one phase winding is measured. An intermodulation signal component, induced in the rotary current machine by slotting effects and magnetic saturation effects, which is determined from the current waveform measured in the at least one phase winding, is used for controlling the rotary current machine.

Low speed and high speed estimates of rotor angle and speed relative to the stator are received from a low speed estimator and a high speed estimator, respectively. LS_θ_EST and a subset of torque-controlling I_Q trajectory curve (“IQTC”) parameter values appropriate to low speed rotor operation are selected for rotor speeds below a low speed threshold value ω_LOW_THRS. HS_θ_EST and a subset of IQTC curve parameter values appropriate to high speed rotor operation are selected for rotor speeds above a high speed threshold value ω_HIGH_THRS. LS_θ_EST and the low speed subset of IQTC parameter values remain selected for rotor speeds less than ω_HIGH_THRS after accelerating to a rotor speed greater than ω_LOW_THRS. HS_θ_EST and the subset of high speed IQTC parameter values remain selected for rotor speeds greater than ω_LOW_THRS after decelerating to a rotor speed less than ω_HIGH_THRS.

Low speed and high speed estimates of rotor angle and speed relative to the stator are received from a low speed estimator and a high speed estimator, respectively. LS_θ_EST and a subset of torque-controlling I_Q trajectory curve (“IQTC”) parameter values appropriate to low speed rotor operation are selected for rotor speeds below a low speed threshold value ω_LOW_THRS. HS_θ_EST and a subset of IQTC curve parameter values appropriate to high speed rotor operation are selected for rotor speeds above a high speed threshold value ω_HIGH_THRS. LS_θ_EST and the low speed subset of IQTC parameter values remain selected for rotor speeds less than ω_HIGH_THRS after accelerating to a rotor speed greater than ω_LOW_THRS. HS_θ_EST and the subset of high speed IQTC parameter values remain selected for rotor speeds greater than ω_LOW_THRS after decelerating to a rotor speed less than ω_HIGH_THRS.

A method for mitigating voltage disturbances at a point of interconnection (POI) of a grid-forming inverter-based resource (IBR) due to flicker includes receiving a voltage reference command and a voltage feedback. The voltage feedback contains information indicative of the voltage disturbances at the POI due to the flicker. The method also includes determining a power reference signal for the IBR based on the voltage reference command and the voltage feedback. Moreover, the method includes generating a current vector reference signal based on the power reference signal, the current vector reference signal containing a frequency component of the voltage disturbances. Further, the method includes generating a transfer function of a regulator based on the frequency component to account for the flicker effect. In addition, the method includes generating a current vector based on a comparison of the current vector reference signal and a current vector feedback signal. Thus, the method includes regulating a voltage vector command using the current vector to mitigate the voltage disturbances.

A method for mitigating voltage disturbances at a point of interconnection (POI) of a grid-forming inverter-based resource (IBR) due to flicker includes receiving a voltage reference command and a voltage feedback. The voltage feedback contains information indicative of the voltage disturbances at the POI due to the flicker. The method also includes determining a power reference signal for the IBR based on the voltage reference command and the voltage feedback. Moreover, the method includes generating a current vector reference signal based on the power reference signal, the current vector reference signal containing a frequency component of the voltage disturbances. Further, the method includes generating a transfer function of a regulator based on the frequency component to account for the flicker effect. In addition, the method includes generating a current vector based on a comparison of the current vector reference signal and a current vector feedback signal. Thus, the method includes regulating a voltage vector command using the current vector to mitigate the voltage disturbances.

An estimation device includes a phase current determination unit, a time difference calculation unit, and an estimation unit. The phase current determination unit performs a determination process for determining values of phase currents based on the value of the bus current detected by a bus current detection unit and states of gate pulse signals. The time difference calculation unit calculates a difference between a detection time of the bus current used in a previous determination process and a detection time of the bus current used in a present determination process. The estimation unit estimates at least one of a position and a speed of an AC motor based on the values of the phase currents determined by the phase current determination unit and the difference calculated by the time difference calculation unit.

An estimation device includes a phase current determination unit, a time difference calculation unit, and an estimation unit. The phase current determination unit performs a determination process for determining values of phase currents based on the value of the bus current detected by a bus current detection unit and states of gate pulse signals. The time difference calculation unit calculates a difference between a detection time of the bus current used in a previous determination process and a detection time of the bus current used in a present determination process. The estimation unit estimates at least one of a position and a speed of an AC motor based on the values of the phase currents determined by the phase current determination unit and the difference calculated by the time difference calculation unit.

A drive device for an AC motor includes: an adaptive observation unit that adaptively estimates an angular velocity of a rotor of an AC motor; a speed control unit that determines a first torque command with which an angular velocity command matches an average value of an estimated angular velocity; a phase lead amount calculation unit that calculates, based on a disturbance frequency, a phase lead amount of a transfer function from a true angular velocity to a model deviation; a vibration suppression control unit that determines, based on a frequency of load torque pulsations, the model deviation, and the phase lead amount, a second torque command with which speed pulsations in the AC motor are suppressed; and a torque control unit that controls a torque of the AC motor based on the first torque command and the second torque command.

A motor control apparatus includes: a current supply unit configured to supply a coil current to a plurality of coils of a motor by controlling a voltage to be applied to the plurality of coils, based on a first command value of an excitation current and a second command value of a torque current; and a control unit configured to control the first command value based on a rotation speed of a rotor of the motor, wherein the control unit is further configured to control, when the rotation speed of the rotor is lower than a first threshold value, the first command value to cause the excitation current to be larger than zero, and control the second command value to supply the torque current in accordance with a load of the rotor.

A motor control system includes a reference current generator that generates a reference current based on a command, a motor voltage providing device that generates a phase voltage based on the reference current, a high frequency voltage, and a feedback current and provides a motor with the phase voltage, and a high frequency voltage generator that generates the high frequency voltage corresponding to a magnitude of voltage generated based on the reference current and the feedback current.