Abstract: A voltage converter for an aircraft electrical system includes an input power line configured to receive input electrical power, an output power line configured to supply output electrical power to aircraft loads, conversion circuitry, and a controller. The conversion circuitry is configured to convert the input electrical power to supply the output electrical power based on one or more control parameters. The controller is configured to receive data relating to the aircraft loads and modify at least one control parameter based on the data.

Abstract: An electric motor system that comprises a motor that comprises a rotor having a magnet mounted thereto and a stator that comprises one or more motor phase windings for driving rotation of the rotor when the motor phase windings receive an input voltage from an electrical power supply. The system has a controller that executes a back “EMF” observer that is operable to estimate a rotor angle by observing a back electromotive force induced in the stator by the rotor. Filtering is applied to the back EMF signal to reduce harmonics prior to determining the rotor angle.

Abstract: Methods of operating electric motor systems that comprise electric motors comprising a rotor having a magnet mounted thereto. The electric motor is initially operated in an open loop mode in which the rotor angle is estimated based on the input voltage frequency. Once the motor is running at sufficient speed, a transition to closed loop mode operation is performed, wherein the rotor angle is determined using an observed back EMF. To provide a smoother open loop to closed loop transition, the rotor angle is determined during a transition period as a function of both the open loop rotor angle and the closed loop rotor angle.

Abstract: A closed loop control system for controlling a plant comprises a controller includes an input arranged to receive a feedback signal from the plant. The controller is arranged to compare a value of the feedback signal to a set point value x(s) and to produce an error signal ?(s) that is at least partially dependent on a difference between the value of the feedback signal and the set point value. The controller also includes an output arranged to supply the error signal ?(s) to the plant. A monitor is arranged to compare a value of the error signal ?(s) produced by the controller to a threshold value and to produce a warning signal when the value of the error signal ?(s) exceeds the threshold value for a period of time greater than a predetermined period.

Abstract: A closed loop control system for controlling a plant comprises a controller includes an input arranged to receive a feedback signal from the plant. The controller is arranged to compare a value of the feedback signal to a set point value x(s) and to produce an error signal c(s) that is at least partially dependent on a difference between the value of the feedback signal and the set point value. The controller also includes an output arranged to supply the error signal c(s) to the plant. A monitor is arranged to compare a value of the error signal c(s) produced by the controller to a threshold value and to produce a warning signal when the value of the error signal c(s) exceeds the threshold value for a period of time greater than a predetermined period.