A power conversion device includes an inverter, a current detector, a frequency analysis processor, a storage, a determination unit, a reference rotational rate change unit, and a rate controller. The determination unit determines a frequency at which a signal component having a magnitude exceeding a prescribed value has been detected among frequency components of a load current, generates restriction information for excluding a reference rotational rate for a rotational rate corresponding to the detected frequency based on a determination result after the determination, and causes the storage to store the generated restriction information. The reference rotational rate change unit changes a reference rotational rate of an electric motor so that mechanical resonance of the detected frequency is avoided based on the stored restriction information. The rate controller controls a rotational rate of the inverter using the changed reference rotational rate. The electric motor is driven at the controlled rotational rate.

According to various embodiments, an electronic device may comprise a housing, a plate coupled to the housing to reciprocate, a flexible display including a first portion disposed on the plate and a second portion extending from the first portion and exposed to an outside or retracted into an inside of the housing as the plate reciprocates, a motor configured to move the plate, at least one electronic component, a battery, and at least one processor. The at least one processor may be configured to identify an event for triggering a movement of the plate, identify a first power of the battery and a second power for controlling the flexible display and the at least one electronic component, based on the event, identify a third power for controlling the motor, based on the first power and the second power, and provide the motor with a signal corresponding to the third power.

A robot apparatus equipped with a driving source includes a power transmission module configured to transmit power to the driving source, a power reception module configured to receive the power transmitted by the power transmission module, and a control device configured to control a power transmission start timing in such a manner that the power reception module receives predetermined power at a timing at which the driving source operates.

The present invention relates to a method for controlling a tool string having a downhole self-propelling wireline tool having wheels rotated by means of hydraulics and connected to projectable arm assemblies projected by hydraulics, comprising running a downhole self-propelling wireline tool into a wellbore, the downhole self-propelling wireline tool being connected to a second end of a wireline, and a first end of the wireline being connected to a power supply, the downhole self-propelling wireline tool having a tool body and a plurality of wheels rotated by means of hydraulics, and each wheel being connected to a projectable arm assembly projectable from the tool body by means of hydraulic fluid from a first hydraulic pump, the downhole self-propelling wireline tool having an electric motor rotating at an operational rotational speed for driving the first pump; supplying electric power to the downhole self-propelling wireline tool to operate the downhole self-propelling wireline tool at a first speed to urge the downhole self-propelling wireline tool through the wellbore at a first force; determining a motor output torque of the electric motor; determining a maximum allowable motor rotational speed based on the motor output torque; and comparing the operational rotational speed with the maximum allowable motor rotational speed, wherein the method further comprises adjusting the operational rotational speed of the electric motor based on the comparison in order to adjust the first speed to a second speed if the operational rotational speed is higher than the maximum allowable motor rotational speed. The invention also relates to a hydraulically driven downhole self-propelling wireline tool configured to perform the method.

A computer implemented method for controlling commutation of a brushless DC (BLDC) motor. The method includes controlling a switching array to drive the BLDC motor at a first commutation, receiving and monitoring power consumption signals indicating power consumption of the BLDC motor, determining whether the power consumption exceeds a first threshold value, and controlling the switching array to drive the BLDC motor at a second commutation when the power consumption exceeds the first threshold value.

A method for providing grid-forming control of a double-fed wind turbine generator connected to an electrical grid includes receiving at least one control signal associated with a desired total power output or a total current output of the double-fed wind turbine generator. The method also includes determining a contribution of at least one of power or current from the line-side converter to the desired total power output or to the total current output of the double-fed wind turbine generator, respectively. The method also includes determining a control command for a stator of the double-fed wind turbine generator based on the contribution of at least one of the power or the current from the line-side converter and the at least one control signal. Further, the method includes using the control command to regulate at least one of power or current in the stator of the double-fed wind-turbine generator.

A method for providing grid-forming control of a double-fed wind turbine generator connected to an electrical grid includes receiving at least one control signal associated with a desired total power output or a total current output of the double-fed wind turbine generator. The method also includes determining a contribution of at least one of power or current from the line-side converter to the desired total power output or to the total current output of the double-fed wind turbine generator, respectively. The method also includes determining a control command for a stator of the double-fed wind turbine generator based on the contribution of at least one of the power or the current from the line-side converter and the at least one control signal. Further, the method includes using the control command to regulate at least one of power or current in the stator of the double-fed wind-turbine generator.

A power detecting device includes a vehicle driving system, a battery detecting module and a controlling module. A first stator winding and a second stator winding are synchronized and connected in parallel with each other. A first end of a first current sensor is coupled to a first-phase winding end of the first stator winding for measuring a first-phase current. A first end of a second current sensor is coupled to a second-phase winding end of the first stator winding for measuring a second-phase current. The battery detecting module is coupled to a first power supply for measuring a current signal and a voltage signal. A controller generates a first power according to the current signal and the voltage signal and generates a second power according to a plurality of data from a database. The controller compares the first power with the second power to generate a detecting result.

A method and a ventilator system designed to carry out the method. The method is used to ascertain a current operating point of a ventilator unit having a ventilator and at least one filter. By determining the current operating point, a conclusion can also be drawn regarding the degree of clogging of the filter. It can also be identified whether the filter is present or not. At multiple points in time, a power value for the electrical power of the ventilator can be ascertained. In accordance with the current speed of the ventilator, a power characteristic curve can be selected from a characteristic map or calculated on the basis of a reference characteristic curve which describes the relationship between the electrical power of the ventilator and the pressure differential of the ventilation unit. The power characteristic curve therefore does not only relate to the ventilator but rather to the entire ventilator unit. This allows clear and sufficiently precise determination of the current operating point A of the ventilator unit.

A laundry treatment machine includes a washing tub, a washing tub motor, a water level sensor, a drain pump, a motor to operate the drain pump, a converter to output DC power, an inverter to convert the DC power into AC power, and a controller to, when power consumed by the motor during a drainage operation does not reach first power, perform control to increase a speed of the motor or the power consumed by the motor, and when the power consumed by the motor during the drainage operation reaches the first power and remains within a first range corresponding to the first power and then falls from the first range, output a drainage completion message. Accordingly, it is possible to quickly and accurately determine the completion of the operation of the drain pump. Therefore, it is possible to shorten the drainage time and reduce the waste of power.