108 results about "Load angle" patented technology

A motor control apparatus includes an inverter circuit for supplying driving power to a motor, a motor current detector for detecting current flowing through the motor, an inverter controller for controlling the inverter circuit based on the output of the detector. The inverter controller has a setting unit for setting various command values to control motor driving status, and a processing unit for controlling the inverter circuit based on the setting on the setting unit. The setting unit sets command value so that a load angle which is an angle between rotor axis and motor applied voltage is operated on the smaller side of the angle that provides the maximum output torque in the load angle-output torque characteristics.

A stepper motor system and apparatus use a position-feedback device, which may have a resolution capability as low as 200 counts per motor shaft revolution, for misstep detection and motor step recovery. In use of the system, position deviation is computed periodically and cyclically, by subtracting the feedback position from the corresponding commanded position, to determine the load angle, implicitly, and the operating status of the motor. If the load angle is within an established allowable range of values, normal stepper operation along the programmed trajectory is maintained, without adjustment. A load angle that exceeds the limits of that range however indicates that a misstep has occurred, and the system controller initiates immediate action to recover lost motor steps, to reestablish synchronism, and to then continue toward the final target position, with minimal loss of time.

The invention relates to a method of operating a synchronous motor (1) having a stator comprising a set of electromagnets (7, 9) and having a permanent magnet rotor (5), wherein the synchronous motor (1) is controlled by calculating in a flux controller (f) a measure of a flux magnitude, which is the magnitude of the stator flux of the motor (1), and is controlled by calculating in a load angle controller (g) a measure of a load angle. Information about a desired motor torque or a reduced motor torque, which is smaller than the desired motor torque, is input to the load angle controller (g) and the load angle controller (g) calculates the measure of the load angle depending on the input motor torque. The measure of the flux magnitude is combined with the measure of the load angle to obtain commands for controlling electric currents of electromagnets of the stator, thereby directly controlling the stator flux. A flux limit value which depends on a predetermined maximum value of the stator flux allowed for the motor (1), which depends on a maximum value of an electric voltage, which is used to drive the currents through the stator electromagnets (7, 9), and which depends on the actual rotor speed is repeatedly calculated. During acceleration of the rotor (5) while the stator flux is smaller than the maximum flux allowed for the motor the measure of the flux magnitude is calculated depending on the output of a predetermined function, wherein the output of the predetermined function depends on the desired motor torque and corresponds to the magnitude of the stator flux, which results in the desired motor torque using the minimum possible stator current. The measure of the load angle is calculated depending on the desired motor torque.

Method for defining quadrature-axis magnetizing inductance of a synchronous machine, the synchronous machine being supplied by an inverter. The method comprises steps, wherein the synchronous machine is started without load or with reduced load; the rotor current of the synchronous machine is kept substantially at zero, the synchronous machine is accelerated to initial angular velocity of measurement, the load angle (ds) of the synchronous machine is guided substantially to 90 degrees, the stator voltage (us), the stator current (is) and the electrical angular velocity (?) of the synchronous machine is defined and the quadrature-axis magnetizing inductance of the synchronous machine (lmq) is defined on the basis of the stator voltage (us), the stator current (is) and the electrical angular velocity (?) of the machine.