Permanent magnet motors (PMMs) can develop oscillations during motor startup that can cause damage to electric submersible pump (ESP) components. A system and method are presented for identifying mechanical and/or electrical caused oscillations in a PMM through the analysis of oscillations in current and torque measurements. A control system within a surface motor controller receives current and/or torque measurements from downhole sensors. The control system employs one or more algorithms designed to detect oscillations in the measurements. Upon detecting oscillations that are consistent with oscillations in the motor from mechanical or electrical causes, the control system automatically initiates protective action to prevent damage to the ESP components.

A rotor for an electrically excited drive machine includes: a coil per rotor pole with, in each case, one first energizable coil unit, and a rotor core for holding the coils of the rotor poles. The coils have, in each case, at least one second energizable coil unit per rotor pole. The rotor has an interconnecting unit which is designed to interconnect the at least two coil units per coil in a manner which is dependent on an operating point of the electric drive machine in order to set the number of windings of the coil, and in order to electrically connect the coils of the rotor poles for configuring a rotor winding with an overall number of windings which is dependent on the numbers of windings of the coils.

To provide a controller for AC rotary electric machine which can control considering the interlinkage fluxes of first-axis and second-axis which change mutually according to the currents of first-axis and second-axis, such as d-axis and q-axis. A controller for AC rotary electric machine calculates interlinkage flux model response values of first-axis and second-axis by performing a response delay processing of a model response to the interlinkage flux command values of first-axis and second-axis; and calculates voltage command values of first-axis and second-axis which make interlinkage fluxes of first-axis and second-axis change to the interlinkage flux model response values of first-axis and second-axis in a feedforward manner, based on the interlinkage flux model response values of first-axis and second-axis, and the electrical angle speed.

To provide a controller for AC rotary electric machine which can control considering the interlinkage fluxes of first-axis and second-axis which change mutually according to the currents of first-axis and second-axis, such as d-axis and q-axis. A controller for AC rotary electric machine calculates interlinkage flux model response values of first-axis and second-axis by performing a response delay processing of a model response to the interlinkage flux command values of first-axis and second-axis; and calculates voltage command values of first-axis and second-axis which make interlinkage fluxes of first-axis and second-axis change to the interlinkage flux model response values of first-axis and second-axis in a feedforward manner, based on the interlinkage flux model response values of first-axis and second-axis, and the electrical angle speed.

A method of actuating an article using a servo actuation system is disclosed. The system comprises a motor, a controller and an inverter. The controller comprises a position controller, a velocity controller and a current controller; the position controller outputs velocity demands to the velocity controller, the velocity controller outputs current demands to the current controller, and the current controller outputs voltage demands to the inverter. The inverter outputs inverted voltage demands to the motor. The method comprises: determining a parameter downstream of the inverter; calculating a limiting value from the parameter and a defined supply power limit; and applying the limiting value in the controller to ensure that the power drawn by the servo actuation system remains within the defined supply power limit.

The present disclosure provides a predictive control method of current increment for a permanent magnet synchronous motor includes: substituting a mathematical expression of a stator voltage during one control period into a continuous time domain current model to obtain a discrete current prediction model and a predicted current at the next time point; obtaining a predicted current increment from a current increment prediction model by subtracting a predictive current at a present time point from a predictive current at a next time point; establishing a cost function according to a preset reference current increment and the predicted current increment; obtaining an optimal voltage increment by minimizing the cost function; superposing the optimal voltage increment on a stator voltage of a present control period to obtain an optimal stator voltage of a next control period for controlling control the permanent magnet synchronous motor.

The present disclosure provides a predictive control method of current increment for a permanent magnet synchronous motor includes: substituting a mathematical expression of a stator voltage during one control period into a continuous time domain current model to obtain a discrete current prediction model and a predicted current at the next time point; obtaining a predicted current increment from a current increment prediction model by subtracting a predictive current at a present time point from a predictive current at a next time point; establishing a cost function according to a preset reference current increment and the predicted current increment; obtaining an optimal voltage increment by minimizing the cost function; superposing the optimal voltage increment on a stator voltage of a present control period to obtain an optimal stator voltage of a next control period for controlling control the permanent magnet synchronous motor.

A synchronous machine includes a stator with stator windings connected with stator terminals to an electrical grid and a rotor with rotor windings rotatable mounted in the stator, wherein a voltage regulator of the synchronous machine is adapted for outputting an excitation signal to adjust a current in the rotor windings for controlling the synchronous machine. A method for determining control parameters for the voltage regulator includes (i) receiving a first time series of values of the excitation signal and a second time series of measurement values of the terminal voltage in the stator terminals, (ii) determining coefficients of a system transfer function of the synchronous machine, and (iii) determining the control parameters for the voltage regulator from the coefficients of the system transfer function.

A synchronous machine includes a stator with stator windings connected with stator terminals to an electrical grid and a rotor with rotor windings rotatable mounted in the stator, wherein a voltage regulator of the synchronous machine is adapted for outputting an excitation signal to adjust a current in the rotor windings for controlling the synchronous machine. A method for determining control parameters for the voltage regulator includes (i) receiving a first time series of values of the excitation signal and a second time series of measurement values of the terminal voltage in the stator terminals, (ii) determining coefficients of a system transfer function of the synchronous machine, and (iii) determining the control parameters for the voltage regulator from the coefficients of the system transfer function.

The present disclosure relates to a circuit device for demagnetizing the rotor of an externally excited synchronous machine and to a method for operating the circuit device.