Systems and methods for interior permanent magnet synchronous motor control

A method for robust control of a sensorless interior permanent magnet synchronous motor (“IPMSM”) during a severe operating condition, the IPMSM having a stator, a rotor, and a motor control system including a multi-model stator flux observer, the method comprising:

• estimating, with a voltage motor model of the multi-model stator flux observer of the sensorless IPMSM, a voltage motor model based estimated motor flux linkage between the stator and rotor during the severe operating condition;
• estimating, with a motor magnetic model of the multi-model stator flux observer of the sensorless IPMSM, a motor magnetic model based estimated motor flux linkage between the stator and rotor during the severe operating condition;
• estimating, with the motor control system, a transition rotor characteristic of the sensorless IPMSM during the severe operating condition;
• outputting, from the multi-model stator flux observer, a plurality of estimated motor characteristics for controlling the sensorless IPMSM during the severe operating condition;
• transitioning multi-model stator flux observer output at a transition threshold stored in memory based on the estimated transition rotor characteristic, the transitioning being between the plurality of estimated motor characteristics for controlling the sensorless IPMSM being estimated as a function of the motor magnetic model based estimated motor flux linkage and the plurality of estimated motor characteristics for controlling the IPMSM being estimated as a function of the voltage motor model based estimated motor flux linkage;
• receiving, at the motor control system, the plurality of estimated motor characteristics;
• and
• controlling, with dynamic direct flux control at the motor control system, the sensorless IPMSM during the severe operating condition based on the plurality of estimated motor characteristics;
• the estimated transition rotor characteristic being an estimated rotor speed,
• wherein the voltage motor model is based upon one or more empirically determined motor parameters, the voltage motor model being valid for a range of operating conditions;
• wherein the motor magnetic model is based upon one or more empirically determined motor parameters, the motor magnetic model being valid for a range of operating conditions;
• wherein the severe operating condition falls within the range of valid operating conditions for at least one of the voltage motor model and the motor current model.

A method for robust control of a sensorless interior permanent magnet synchronous motor (“IPMSM”) during a severe operating condition, the IPMSM having a stator, a rotor, and a motor control system including a multi-model stator flux observer, the method comprising:

• estimating, with a voltage motor model of the multi-model stator flux observer of the sensorless IPMSM, a voltage motor model based estimated motor flux linkage between the stator and rotor during the severe operating condition;
• estimating, with a motor magnetic model of the multi-model stator flux observer of the sensorless IPMSM, a motor magnetic model based estimated motor flux linkage between the stator and rotor during the severe operating condition;
• estimating, with the motor control system, a transition rotor characteristic of the sensorless IPMSM during the severe operating condition;
• outputting, from the multi-model stator flux observer, a plurality of estimated motor characteristics for controlling the sensorless IPMSM during the severe operating condition;
• transitioning multi-model stator flux observer output at a transition threshold stored in memory based on the estimated transition rotor characteristic, the transitioning being between the plurality of estimated motor characteristics for controlling the sensorless IPMSM being estimated as a function of the motor magnetic model based estimated motor flux linkage and the plurality of estimated motor characteristics for controlling the IPMSM being estimated as a function of the voltage motor model based estimated motor flux linkage;
• receiving, at the motor control system, the plurality of estimated motor characteristics;
• and
• controlling, with dynamic direct flux control at the motor control system, the sensorless IPMSM during the severe operating condition based on the plurality of estimated motor characteristics;
• injecting a high frequency current into the stator of the IPMSM;
• sensing a stator current including a fundamental frequency portion and a high frequency injection portion;
• filtering the sensed stator current with a dynamic high frequency injection (“DHFI”) filter into a DHFI filtered current;
• estimating a rotor position of the sensorless IPMSM with a high frequency observer based on the DHFI filtered current;
• wherein estimating the motor magnetic model based estimated motor flux linkage includes estimating the motor magnetic model based estimated motor flux linkage based on the DHFI filtered current, the estimated rotor position, and the motor magnetic model;
• and
• wherein estimating the voltage motor model based estimated motor flux linkage includes estimating the voltage motor model based estimated motor flux linkage based on the DHFI filtered current;
• and
• estimating a rotor position of the sensorless IPMSM based on the estimated voltage motor model-based motor flux linkage.

A sensorless interior permanent magnet synchronous motor (“IPMSM”) system for operation during a severe operating condition, the sensorless IPMSM system comprising:

• a motor housing;
• a stator mounted in the motor housing and defining a space, the stator having a three-phase stator winding configuration;
• a rotor including a plurality of interior permanent magnets distributed circumferentially such that the rotor exhibits magnetic saliency, the rotor being rotatable over a speed range inside the space via excitation of the three-phase stator winding configuration of the stator;
• a motor control system mounted in the motor housing including:
• a power supply;
• a sensing circuit configured to sense one or more electrical characteristics of the stator;
• a memory for storing a plurality of motor characteristic values;
• a multi-model stator flux observer configured to:
• estimate, with a voltage motor model, a voltage motor model based estimated motor flux linkage between the stator and rotor during the severe operating condition,
• estimate, with a motor magnetic model, a motor magnetic model based estimated motor flux linkage between the stator and rotor during the severe operating condition,
• estimate a rotor speed based on at least one of the voltage motor model based estimated motor flux linkage and the motor magnetic model based estimated motor flux linkage, and
• output the plurality of estimated motor characteristic values for controlling the sensorless IPMSM during the severe operating condition based on the estimated rotor speed, the plurality of estimated motor characteristic values being estimated as a function of at least one of the motor magnetic model based estimated motor flux linkage and voltage motor model based estimated motor flux linkage;
• a dynamic direct flux controller configured to generate driving commands during the severe operating condition based on the plurality of estimated motor characteristics;
• a driving circuit for generating excitation signals for the three-phase stator winding configuration of the stator according to the driving commands provided by the controller;
• and
• wherein the multi-model stator flux observer is configured to output the plurality of estimated motor characteristic values as a function of the motor magnetic model based estimated motor flux linkage while the estimated rotor speed is below a motor magnetic model threshold, and configured to output the plurality of estimated motor characteristic values as a function of the voltage model based estimated motor flux linkage while the estimated rotor speed is above a voltage model threshold.

A sensorless interior permanent magnet synchronous motor (“IPMSM”) system for operation during a severe operating condition, the sensorless IPMSM system comprising:

• a motor housing;
• a stator mounted in the motor housing and defining a space, the stator having a three-phase stator winding configuration;
• a rotor including a plurality of interior permanent magnets distributed circumferentially such that the rotor exhibits magnetic saliency, the rotor being rotatable over a speed range inside the space via excitation of the three-phase stator winding configuration of the stator;
• a motor control system mounted in the motor housing including:
• a power supply;
• a sensing circuit configured to sense one or more electrical characteristics of the stator;
• a memory for storing a plurality of motor characteristic values;
• a multi-model stator flux observer configured to:
• estimate, with a voltage motor model, a voltage motor model based estimated motor flux linkage between the stator and rotor during the severe operating condition,
• estimate, with a motor magnetic model, a motor magnetic model based estimated motor flux linkage between the stator and rotor during the severe operating condition,
• estimate a rotor speed based on at least one of the voltage motor model based estimated motor flux linkage and the motor magnetic model based estimated motor flux linkage, and
• output the plurality of estimated motor characteristic values for controlling the sensorless IPMSM during the severe operating condition based on the estimated rotor speed, the plurality of estimated motor characteristic values being estimated as a function of at least one of the motor magnetic model estimated motor flux linkage and voltage motor model estimated motor flux linkage;
• a dynamic direct flux controller configured to generate driving commands during the severe operating condition based on the plurality of estimated motor characteristics;
• a driving circuit for generating excitation signals for the three-phase stator winding configuration of the stator according to the driving commands provided by the controller;
• and
• wherein the voltage model is based upon one or more empirically determined motor parameters, the voltage model being valid for a range of operating conditions, wherein at estimated rotor speeds below the voltage model threshold, the severe operating condition falls outside the range of operating conditions where the voltage model is valid, and wherein at estimated rotor speeds above the voltage model threshold, the severe operating condition falls within the range of operating conditions where the voltage model is valid;
• and
• wherein the motor magnetic model is based upon one or more empirically determined motor parameters, the magnetic model being valid for a range of operating conditions, wherein at estimated rotor speeds above the current model threshold, the severe operating condition falls outside the range of operating conditions where the magnetic model is valid, and wherein at estimated rotor speeds below the current model threshold, the severe operating condition falls within the range of operating conditions where the magnetic model is valid.

A sensorless interior permanent magnet synchronous motor (“IPMSM”) system for operation during a severe operating condition, the sensorless IPMSM system comprising:

• a motor housing;
• a stator mounted in the motor housing and defining a space, the stator having a three-phase stator winding configuration;
• a rotor including a plurality of interior permanent magnets distributed circumferentially such that the rotor exhibits magnetic saliency, the rotor being rotatable over a speed range inside the space via excitation of the three-phase stator winding configuration of the stator;
• a motor control system mounted in the motor housing including:
• a power supply;
• a sensing circuit configured to sense one or more electrical characteristics of the stator;
• a memory for storing a plurality of motor characteristic values;
• a multi-model stator flux observer configured to:
• estimate, with a voltage motor model, a voltage motor model based estimated motor flux linkage between the stator and rotor during the severe operating condition,
• estimate, with a motor magnetic model, a motor magnetic model based estimated motor flux linkage between the stator and rotor during the severe operating condition,
• estimate a rotor speed based on at least one of the voltage motor model based estimated motor flux linkage and the motor magnetic model based estimated motor flux linkage, and
• output the plurality of estimated motor characteristic values for controlling the sensorless IPMSM during the severe operating condition based on the estimated rotor speed, the plurality of estimated motor characteristic values being estimated as a function of at least one of the motor magnetic model estimated motor flux linkage and voltage motor model estimated motor flux linkage;
• a dynamic direct flux controller configured to generate driving commands during the severe operating condition based on the plurality of estimated motor characteristics;
• a driving circuit for generating excitation signals for the three-phase stator winding configuration of the stator according to the driving commands provided by the controller;
• and
• a high frequency injection circuit configured to inject a high frequency signal into the stator of the IPMSM;
• wherein the sensing circuit is configured to sense a stator current including a fundamental frequency portion and a high frequency injection portion;
• a dynamic high frequency injection (“DHFI”) filter configured to filter the sensed stator current into a DHFI filtered current;
• a high frequency angle observer configured to estimate a rotor position of the sensorless IPMSM based on the DHFI filtered current;
• and
• wherein the multi-model stator flux observer is configured to estimate the motor magnetic model based estimated motor flux linkage based on the DHFI filtered current, the estimated rotor position, and the motor magnetic model.

A method for estimating a sensorless interior permanent magnet synchronous motor (“IPMSM”) rotor characteristic value during severe operating conditions with a multi-model stator flux observer of an IPMSM control system, the IPMSM having a stator and a rotor, the method comprising:

• estimating, with a voltage motor model of the multi-model stator flux observer of the IPMSM control system, a motor voltage model voltage motor model based estimated motor flux linkage between the stator and rotor based on back-EMF voltage and dead time voltage;
• estimating, with a motor magnetic model of the multi-model stator flux observer of the IPMSM control system, a motor magnetic model based estimated motor flux linkage between the stator and rotor based on stator current and rotor position;
• and
• estimating the sensorless IPMSM rotor characteristic value as a function of the motor magnetic model estimated motor flux linkage;
• estimating the sensorless IPMSM rotor characteristic value as a function of the voltage motor model estimated motor flux linkage;
• transitioning multi-model stator flux observer output at a transition threshold stored in memory, between outputting the sensorless IPMSM rotor characteristic value estimated as a function of the motor magnetic model estimated motor flux linkage and the sensorless IPMSM rotor characteristic value estimated as a function of the voltage motor model estimated motor flux linkage;
• whereby accuracy of the estimated sensorless IPMSM rotor characteristic output from the multi-model stator flux observer during the severe operating conditions falls within a predefined tolerance range of an actual rotor characteristic value during the severe operating conditions over an entire operating range of the IPMSM control;
• injecting a high frequency signal into the stator of the IPMSM;
• sensing an HFI injected stator current including a fundamental frequency portion and a high frequency injection portion;
• filtering the sensed HFI stator current with dynamic high frequency injection (“DHFI”) filters into a fundamental frequency DHFI filtered current and a high frequency DHFI filtered current;
• estimating a high frequency observer based rotor position of the sensorless IPMSM with a high frequency angle observer based on the high frequency DHFI filtered current, wherein the estimating is based on magnetic saliency of the IPMSM in response to injecting the high frequency signal into the stator of the IPMSM;
• and
• wherein estimating the motor magnetic model based estimated motor flux linkage includes estimating the motor magnetic model based estimated motor flux linkage based on the fundamental frequency DHFI filtered current, the estimated high frequency observer based rotor position, and the motor magnetic model, and wherein estimating the motor magnetic model based estimated motor flux linkage is unaffected by motor parameter variation at rotor speeds below the transition threshold;
• and
• wherein estimating the voltage motor model based estimated motor flux linkage includes estimating the voltage motor model based estimated motor flux linkage based on the fundamental frequency DHFI filtered current, a pre-injection target voltage, back-EMF voltage derived from DHFI filtered current, and dead time voltage.

A method for estimating a sensorless interior permanent magnet synchronous motor (“IPMSM”) rotor characteristic value during severe operating conditions with a multi-model stator flux observer of an IPMSM control system, the IPMSM having a stator and a rotor, the method comprising:

• estimating, with a voltage motor model of the multi-model stator flux observer of the IPMSM control system, a voltage motor model based estimated motor flux linkage between the stator and rotor based on back-EMF voltage and dead time voltage;
• estimating, with a motor magnetic model of the multi-model stator flux observer of the IPMSM control system, a motor magnetic model based estimated motor flux linkage between the stator and rotor based on stator current and rotor position;
• and
• estimating the sensorless IPMSM rotor characteristic value as a function of the motor magnetic model estimated motor flux linkage;
• estimating the sensorless IPMSM rotor characteristic value as a function of the voltage motor model estimated motor flux linkage;
• transitioning multi-model stator flux observer output at a transition threshold stored in memory, between outputting the sensorless IPMSM rotor characteristic value estimated as a function of the motor magnetic model estimated motor flux linkage and the sensorless IPMSM rotor characteristic value estimated as a function of the voltage motor model estimated motor flux linkage;
• whereby accuracy of the estimated sensorless IPMSM rotor characteristic output from the multi-model stator flux observer during the severe operating conditions falls within a predefined tolerance range of an actual rotor characteristic value during the severe operating conditions over an entire operating range of the IPMSM control;
• wherein the sensorless IPMSM rotor characteristic value is estimated:
• at rotor speeds below the transition threshold, as a function of the high frequency observer estimated rotor position,
• at rotor speeds above the transition threshold and below an observer mode threshold, as a function of the stator flux observer estimated rotor position, at rotor speeds above the observer mode threshold and below a high frequency injection disable threshold, as a function of the stator flux observer estimated rotor position and a filtered high frequency injected current,
• at rotor speeds above the high frequency injection disable threshold, as a function of the stator flux observer estimated rotor position and a stator current not subject to high frequency injection.

A method for estimating a sensorless interior permanent magnet synchronous motor (“IPMSM”) rotor characteristic value during severe operating conditions with a multi-model stator flux observer of an IPMSM control system, the IPMSM having a stator and a rotor, the method comprising:

• estimating, with a voltage motor model of the multi-model stator flux observer of the IPMSM control system, a voltage motor model based estimated motor flux linkage between the stator and rotor based on back-EMF voltage and dead time voltage;
• estimating, with a motor magnetic model of the multi-model stator flux observer of the IPMSM control system, a motor magnetic model based estimated motor flux linkage between the stator and rotor based on stator current and rotor position;
• and
• estimating the sensorless IPMSM rotor characteristic value as a function of the motor magnetic model estimated motor flux linkage;
• estimating the sensorless IPMSM rotor characteristic value as a function of the voltage motor model estimated motor flux linkage;
• transitioning multi-model stator flux observer output at a transition threshold stored in memory, between outputting the sensorless IPMSM rotor characteristic value estimated as a function of the motor magnetic model estimated motor flux linkage and the sensorless IPMSM rotor characteristic value estimated as a function of the voltage motor model estimated motor flux linkage;
• whereby accuracy of the estimated sensorless IPMSM rotor characteristic output from the multi-model stator flux observer during the severe operating conditions falls within a predefined tolerance range of an actual rotor characteristic value during the severe operating conditions over an entire operating range of the IPMSM control;
• selecting a transition threshold for a gain function that dictates whether the motor magnetic model based flux estimate or the voltage motor model estimate dominates the feedback, wherein the selecting is based, at least in part, on a rotor speed value corresponding to an observer mode change and a rotor speed value corresponding to a high frequency injection disable;
• and
• wherein the severe operating conditions include one or more of an extreme ambient temperature, a fluctuation in ambient temperature, a fluctuation in voltage, and inverter saturation.

A sensorless interior permanent magnet synchronous motor (“IPMSM”) comprising:

• a motor housing;
• a stator mounted in the motor housing and defining a cylindrical space, the stator having a three-phase stator winding configuration;
• a rotor including a plurality of interior permanent magnets distributed circumferentially such that the rotor exhibits magnetic saliency, the rotor being rotatable over a speed range inside the cylindrical space via excitation of the three-phase stator winding configuration of the stator;
• a motor control system mounted in the motor housing including:
• a power supply;
• a sensing circuit configured to sense a stator current;
• a dynamic high frequency injection (“DHFI”) filter circuit configured to filter the stator current into a fundamental frequency DHFI filtered stator current and a high frequency DHFI filtered stator current;
• a memory for storing rotor position information, motor voltage model information, motor current model information, and a plurality of motor characteristic values;
• a flux observer system including one or more controllers configured to:
• obtain a rotor position estimate based on at least one of the stator current, the high frequency DHFI filtered stator current, and the fundamental frequency DHFI filtered stator current;
• estimate a voltage-model based flux linkage between the stator and the rotor based on the voltage motor model information;
• estimate a current-model based flux linkage between the stator and the rotor based on the current motor model information;
• update the plurality of motor characteristic values in memory based on at least one of the voltage-model based flux linkage and the current-model based flux linkage;
• a dynamic direct flux control system configured to generate driving commands using closed loop control based on feedback including the updated plurality of motor characteristic values;
• a driving circuit for generating excitation signals for the three-phase stator winding configuration of the stator according to the driving commands;
• and
• whereby robust speed control is provided over the entire speed range despite non-linear variation of motor parameters.