Abstract: A system and method for closed-loop startup for a sensorless permanent magnet motor drive are disclosed. The drive provides an output current to a motor. A closed-loop startup subsystem includes a proportional integral closed-loop controller determining an optimal current command to maintain synchronization of the motor during a change in speed. The controller is configured to determine a power difference between an actual motor power output and an ideal motor power output, determines the optimal electric current command based on the power difference, and apply the optimal electric current command to adjust the output current to reduce the power difference. The controller may include an acceleration feedforward mechanism configured to determine and add an acceleration feedforward current component to the output electric current to compensate for the effects of inertia and friction. Additionally, for each torque current command applied, the controller may add a q-axis current offset.

Abstract: A static auto-tuning system and method for controlling operation of a motor in a system. A speed reference signal is generated resulting in a speed response of the motor. Closed-loop feedback magnifies the rotating friction effect to an observable level. Inertia and rotating friction coefficient values of the system are estimated based on the speed frequency response and a virtual damping coefficient. A fixed low frequency speed signal may result in a first frequency response function for determining virtual damping, and a variable frequency excitation signal may result in a second frequency response function for determining the inertia and rotating friction characteristics. Closed-loop gains are determined based on these characteristics. The excitation signal may be sampled and a peak value in each interval may be identified and stored to produce an envelope of peak values for determining the gain response. Operation of the motor is controlled using the determined gains.

Abstract: An adaptive speed control system and method for adapting control of an electric motor under a changing load condition. A load torque observer determines a load torque value when the motor is operating at a constant speed, and the load torque value is used to adapt a torque. An inertia observer determines an inertia load value when the motor is operating at a changing speed, and the inertia load value is used to adapt a controller gain. An active disturbance input decoupler provides disturbance rejection when the motor is operating at a constant speed. An adaptive control switch switches the load torque observer between driving the inertia observer and driving the active disturbance input decoupler. The system may be configured for a multi-axis system in which multiple motors are each associated with a different axis of motion, and multiple adaptive speed control systems are each associated with a different motor.

Abstract: An adaptive speed control system and method for adapting control of an electric motor under a changing load condition. A load torque observer determines a load torque value when the motor is operating at a constant speed, and the load torque value is used to adapt a torque. An inertia observer determines an inertia load value when the motor is operating at a changing speed, and the inertia load value is used to adapt a controller gain. An active disturbance input decoupler provides disturbance rejection when the motor is operating at a constant speed. An adaptive control switch switches the load torque observer between driving the inertia observer and driving the active disturbance input decoupler. The system may be configured for a multi-axis system in which multiple motors are each associated with a different axis of motion, and multiple adaptive speed control systems are each associated with a different motor.

Abstract: A static auto-tuning system and method for controlling operation of a motor in a system. A speed reference signal is generated resulting in a speed response of the motor. Closed-loop feedback magnifies the rotating friction effect to an observable level. Inertia and rotating friction coefficient values of the system are estimated based on the speed frequency response and a virtual damping coefficient. A fixed low frequency speed signal may result in a first frequency response function for determining virtual damping, and a variable frequency excitation signal may result in a second frequency response function for determining the inertia and rotating friction characteristics. Closed-loop gains are determined based on these characteristics. The excitation signal may be sampled and a peak value in each interval may be identified and stored to produce an envelope of peak values for determining the gain response. Operation of the motor is controlled using the determined gains.

Abstract: An adaptive speed control system and method for adapting control of an electric motor under a changing load condition. A load torque observer determines a load torque value when the motor is operating at a constant speed, and the load torque value is used to adapt a torque. An inertia observer determines an inertia load value when the motor is operating at a changing speed, and the inertia load value is used to adapt a controller gain. An active disturbance input decoupler provides disturbance rejection when the motor is operating at a constant speed. An adaptive control switch switches the load torque observer between driving the inertia observer and driving the active disturbance input decoupler. The system may be configured for a multi-axis system in which multiple motors are each associated with a different axis of motion, and multiple adaptive speed control systems are each associated with a different motor.

Abstract: A static auto-tuning system and method for controlling operation of a motor in a system. A speed reference signal is generated resulting in a speed response of the motor. Closed-loop feedback magnifies the rotating friction effect to an observable level. Inertia and rotating friction coefficient values of the system are estimated based on the speed frequency response and a virtual damping coefficient. A fixed low frequency speed signal may result in a first frequency response function for determining virtual damping, and a variable frequency excitation signal may result in a second frequency response function for determining the inertia and rotating friction characteristics. Closed-loop gains are determined based on these characteristics. The excitation signal may be sampled and a peak value in each interval may be identified and stored to produce an envelope of peak values for determining the gain response. Operation of the motor is controlled using the determined gains.

Abstract: A system for braking an electric motor. For each motor winding, a first switch is connected between the winding and electrical ground and in series with a resistor and is closeable to connect the winding to ground through the resistor, and a second switch is connected between the winding and ground and is closeable to bypass the resistor. A controller receives feedback regarding the speed and sends to the second switch a pulse width modulated signal which selectively opens and closes the second switch to connect and disconnect the resistor to achieve an optimal equivalent average stator resistance for the motor speed which results in a power transfer to the resistor and increases a braking torque as the motor slows. The pulse width modulated signal opens the second switch for a longer time when the motor speed is higher and for a shorter time when the motor speed is lower.

Abstract: A system for braking an electric motor. For each motor winding, a first switch is connected between the winding and electrical ground and in series with a resistor and is closeable to connect the winding to ground through the resistor, and a second switch is connected between the winding and ground and is closeable to bypass the resistor. A controller receives feedback regarding the speed and sends to the second switch a pulse width modulated signal which selectively opens and closes the second switch to connect and disconnect the resistor to achieve an optimal equivalent average stator resistance for the motor speed which results in a power transfer to the resistor and increases a braking torque as the motor slows. The pulse width modulated signal opens the second switch for a longer time when the motor speed is higher and for a shorter time when the motor speed is lower.