A power device includes: a DC voltage output circuit that generates a DC internal power voltage from external supply power; a capacitor that is connected to the internal power voltage; and a voltage supply control circuit that monitors a voltage level of the internal power voltage and that, when detecting a drop in the internal power voltage, cuts off supply of the internal power voltage. The power device supplies internal power to a load. The power device supplies, to a first load that is a part of the load, the internal power voltage, and supplies, to a second load that is a load other than the first load, the internal power voltage via the voltage supply control circuit.

A system for the resilience of an electric submersible pumping system to a transient power interruption includes a power backup connected to the variable speed drive of the pumping system. A method for controlling the electric submersible pump during the transient power interruption includes connecting a variable speed drive to a power source, charging one or more rechargeable batteries within the power backup, and connecting the power backup to the variable speed drive. The method continues with the steps of operating the motor with the variable speed drive, detecting a disruption in AC power from the power source to the variable speed drive, and applying power from the power backup to the variable speed drive to operate the motor during the transient interruption in electrical power.

A power device includes: a DC voltage output circuit that generates a DC internal power voltage from external supply power; a capacitor that is connected to the internal power voltage; and a voltage supply control circuit that monitors a voltage level of the internal power voltage and that, when detecting a drop in the internal power voltage, cuts off supply of the internal power voltage. The power device supplies internal power to a load. The power device supplies, to a first load that is a part of the load, the internal power voltage, and supplies, to a second load that is a load other than the first load, the internal power voltage via the voltage supply control circuit.

An intelligent power module and a controller for an air conditioner are provided. For the intelligent power module, an adjust circuit is additionally provided between a respective drive circuit and a respective IGBT transistor. The adjust circuit detects a change in the voltage of a low voltage power supply of the intelligent power module in real time, and disables the output of the module when the voltage is detected to be too low due to fluctuation of the low voltage power supply. This operation releases the charge accumulated in the IGBT transistor, when energy storage of a drive motor causes charge accumulation of the IGBT transistor. The adjust circuit can continue releasing the charge when the low voltage power supply is restored to normal, to prevent the operating reliability of the module from being affected by the impact of the charge on internal circuits of the module.

A capacitor capacitance estimation device including processing circuitry to segment a section signal into a plurality of signals and to generate a plurality of pieces of frequency domain data by converting each of the plurality of signals obtained by the segmentation into a plurality of component values in a frequency domain. Each of the plurality of signals having a predetermined duration. The processing circuitry further configured to extract a component value of a frequency corresponding to a carrier frequency from the plurality of component values in each of the plurality of pieces of frequency domain data, to use the extracted component value as a value at time corresponding to the corresponding one of the extracted signals, and to generate time-series data representing a plurality of the extracted component values in a time series, to estimate a capacitance of a capacitor from processed and filtered time-series data.

The present disclosure relates to a drain pump driving apparatus and a laundry treatment machine including the same. A drain pump driving apparatus according to an embodiment of the present disclosure includes: a converter; an inverter to output converted AC voltage to a drain pump motor; an output current detector to detect an output current flowing in the motor; and a controller to control the inverter, wherein in case in which the speed of the motor increases and the output current flowing in the motor decreases during a predetermined period among an operation period of the drain motor, the controller controls the inverter to be turned off. Accordingly, it is possible to protect internal circuit elements in case the motor loses its synchronism.

A method for determining a resonance frequency of a mechanical system including an electric motor coupled to a mechanical load, the method including: starting the motor by providing a supply voltage using a motor controller; once the electric motor is running at a predefined target rotational speed, applying a first excitation signal comprising a voltage pulse superimposed to the supply voltage; measuring a mechanical response of the mechanical system, using a measurement system coupled to the motor; and analyzing the measured response, to determine at least one resonance frequency of the mechanical system.

A system for the resilience of an electric submersible pumping system to a transient power interruption includes a power backup connected to the variable speed drive of the pumping system. A method for controlling the electric submersible pump during the transient power interruption includes connecting a variable speed drive to a power source, charging one or more rechargeable batteries within the power backup, and connecting the power backup to the variable speed drive. The method continues with the steps of operating the motor with the variable speed drive, detecting a disruption in AC power from the power source to the variable speed drive, and applying power from the power backup to the variable speed drive to operate the motor during the transient interruption in electrical power.

A free piston Stirling refrigerator of the present invention has a cylinder provided inside a casing; a piston and a displacer that are provided in a way such that they are capable of reciprocating inside the cylinder; a linear motor for reciprocating the piston; and a control unit for controlling the operation of the linear motor. Particularly, the control unit has an inverter circuit for generating an alternating current with a given frequency and then supplying the alternating current to the linear motor; a current detection circuit for detecting the current outputted from the inverter circuit; and a control circuit for controlling the output from the inverter circuit based on a turbulence in the current detected by the current detection circuit. Thus, collisions between the piston and the displacer (i.e. hitting) can be restricted through an inexpensive configuration and a simple control.

A functional safety system with high reliability is provided. The functional safety system includes power source apparatuses VS1 and VS2, voltage monitoring apparatuses VM1 and VM2, semiconductor devices SC1 and SC2, interruption circuits IN1 and IN2, and a motor MT. A the voltage converting circuit DA1 of the voltage monitoring apparatus VM1 generates a detected voltage VA1 from a power source voltage VDD1 on the basis of a switching signal VC1, and a voltage converting circuit DA2 of the voltage monitoring apparatus VM1 generates a detected voltage VA2 from the power source voltage VDD1 on the basis of a switching signal VC1.