Disclosed are an inverter control device and method. The method according to an embodiment of the present includes estimating a rotation speed of a motor, determining a slip frequency reference using an energy of a direct current terminal capacitor of an inverter, which provides an output voltage to the motor, and a direct current terminal energy reference when a direct current terminal voltage of the inverter is a certain level or less, and providing a frequency reference determined by adding the rotation speed of the motor and the slip frequency reference to the inverter.

A device is provided for monitoring the compaction of concrete introduced into a slipform of a slipform paver by means of at least one concrete compacting device that has an asynchronous motor for driving an unbalanced mass which generates vibrations. The monitoring device comprises an apparatus for monitoring the stator current of the asynchronous motor, the apparatus being configured such that a change in the compaction of the concrete is determined based on an analysis of the stator current. The apparatus for monitoring the stator current of the asynchronous motor is preferably configured such that the amplitude spectrum of the stator current is determined in order to analyse the stator current. It is advantageous that the compaction of the concrete is not monitored using sensors which are exposed to harsh ambient conditions during operation of the slipform paver.

A device is provided for monitoring the compaction of concrete introduced into a slipform of a slipform paver by means of at least one concrete compacting device that has an asynchronous motor for driving an unbalanced mass which generates vibrations. The monitoring device comprises an apparatus for monitoring the stator current of the asynchronous motor, the apparatus being configured such that a change in the compaction of the concrete is determined based on an analysis of the stator current. The apparatus for monitoring the stator current of the asynchronous motor is preferably configured such that the amplitude spectrum of the stator current is determined in order to analyse the stator current. It is advantageous that the compaction of the concrete is not monitored using sensors which are exposed to harsh ambient conditions during operation of the slipform paver.

A method of controlling an induction generator is provided connected to a utility grid, the method including: receiving an actual grid frequency; and controlling rotor windings of the generator by a rotor control signal having a rotor winding reference frequency being set in dependence of the actual grid frequency.

A method of controlling an induction generator is provided connected to a utility grid, the method including: receiving an actual grid frequency; and controlling rotor windings of the generator by a rotor control signal having a rotor winding reference frequency being set in dependence of the actual grid frequency.

A method of a control system (2200) controls an inductance motor in a blower including an impeller and volute using a pressure compensation control system. The control system may be implemented in a respiratory pressure therapy device. The control system may include a sensor configured to provide a pressure signal indicative of the pressure of a flow of fluid produced by the blower. A measured pressure may be compared to a set pressure to determine a pressure error. A slip frequency may be adjusted as a function of the pressure error in an attempt to eliminate or minimise the pressure error.

An electronic control unit includes calculating a slip frequency of a rotating electric machine from a torque instruction value to the rotating electric machine and a target value of output efficiency to the rotating electric machine, calculating a frequency of the instruction signal from the slip frequency and a rotational frequency of the rotating electric machine, the slip frequency being changed by changing the target value of the output efficiency with the torque instruction value maintained and changing the slip frequency so as to change the frequency of the instruction signal to out of an inverter lock frequency band when the frequency of the instruction signal is included in the inverter lock frequency band.

An electronic control unit includes calculating a slip frequency of a rotating electric machine from a torque instruction value to the rotating electric machine and a target value of output efficiency to the rotating electric machine, calculating a frequency of the instruction signal from the slip frequency and a rotational frequency of the rotating electric machine, the slip frequency being changed by changing the target value of the output efficiency with the torque instruction value maintained and changing the slip frequency so as to change the frequency of the instruction signal to out of an inverter lock frequency band when the frequency of the instruction signal is included in the inverter lock frequency band.

An inverter controller is provided. The controller according to an exemplary embodiment of the present disclosure generates a compensation voltage to compensate an inverter command voltage using motor torque current and motor information, and apply the compensation voltage to the command voltage.

An inverter controller is provided. The controller according to an exemplary embodiment of the present disclosure generates a compensation voltage to compensate an inverter command voltage using motor torque current and motor information, and apply the compensation voltage to the command voltage.