Abstract: A memory device and a dynamic garbage collection method thereof are provided. The method includes receiving a minimum operating speed, ascertaining a reference valid page count ratio (VPC), using a maximum operating speed, the minimum operating speed, and a garbage collection speed, the reference VPC ratio being ascertained by the following formula 1 and determining whether to perform a garbage collection, using the reference VPC ratio and a current average VPC ratio. <Formula 1> Vr=Gp (Jp?Mp)/(Jp*Mp+(Gp*(Jp?Mp))) Here, Vr is the reference VPC ratio, Gp is the garbage collection speed, Jp is the maximum operating speed, and Mp is the minimum operating speed.

Abstract: A method of operating a storage device including a non-volatile memory includes receiving a write command from a host in a first state, receiving write data from the host in a second state, and transitioning an operation state from the second state to one of the first state and a third state based on a write mode chosen. The write command is received in the first state, and the received write data is programmed to the non-volatile memory in the third state.

Abstract: A sealing structure for a turbine includes a recessed portion formed around a rotary body and having an annular shape, an annular packing body fixed in a coupling groove of a stationary body, a support member disposed at a central portion of the packing body, a brush seal, one end of which is fixed to the support member while the other end of the brush seal is disposed in the recessed portion, and a tooth portion disposed in at least one side of the packing body.

Abstract: Disclosed herein is an apparatus for reactor power control of a steam turbine power generation system including a reactor, a high-pressure turbine to which steam is supplied from the reactor through a main steam pipe, a low-pressure turbine to which the steam discharged from the high-pressure turbine is supplied via a moisture separator reheater, a branch pipe branched from the main steam pipe to be connected to the moisture separator reheater, a generator connected to the low-pressure turbine, a condenser for condensing the steam discharged from the low-pressure turbine, a condensate pump for feeding condensate condensed by the condenser, and feed water heaters for heating the condensate, the apparatus including a branch pipe control valve provided on the branch pipe and a control unit for controlling an opening degree of the branch pipe control valve.

Abstract: A method of operating a storage device includes receiving a write task from a host device. The method also includes storing the write task in a task queue included in the storage device. A write execution command is received from the host device. The method includes executing the write task in response to the write execution command and performing an internal management operation of the storage device after the write task is stored in the task queue and before the write execution command is received.

Abstract: The present disclosure relates to a structure for a rotor for removing bearing oil, including a rotor shaft disposed in a casing of a turbine and an annular oil scattering structure formed between an oil deflector and a bearing supporter on the rotor shaft in a circumferential direction to scatter bearing oil flowing from the bearing supporter toward the oil deflector along a surface of the rotor shaft.

Abstract: A sealing structure for a turbine includes a recessed portion formed around a rotary body and having an annular shape, an annular packing body fixed in a coupling groove of a stationary body, a support member disposed at a central portion of the packing body, a brush seal, one end of which is fixed to the support member while the other end of the brush seal is disposed in the recessed portion, and a tooth portion disposed in at least one side of the packing body.

Abstract: A turbine includes a rotor shaft having a plurality of rotating blades mounted on the rotor shaft, a bearing assembly rotatably supporting the rotor shaft, a casing forming a passage of a fluid and to include a space in which the rotating blades are disposed so that thermal energy of the fluid is converted into mechanical energy by rotation, a foundation fixedly supporting the bearing assembly, and a packing device installed in the rotor shaft for sealing between the casing and the rotor shaft and supported by the foundation. The casing comprises a connection unit extended toward the packing device and fixed to the casing so that a location of the connection unit is relatively changed with respect to the packing device. Accordingly, there is an advantage in that the leakage of a fluid is reduced because a clearance between the packing device and the rotor shaft is reduced.

Abstract: Disclosed herein is an apparatus for reactor power control of a steam turbine power generation system including a reactor, a high-pressure turbine to which steam is supplied from the reactor through a main steam pipe, a low-pressure turbine to which the steam discharged from the high-pressure turbine is supplied via a moisture separator reheater, a branch pipe branched from the main steam pipe to be connected to the moisture separator reheater, a generator connected to the low-pressure turbine, a condenser for condensing the steam discharged from the low-pressure turbine, a condensate pump for feeding condensate condensed by the condenser, and feed water heaters for heating the condensate, the apparatus including a branch pipe control valve provided on the branch pipe and a control unit for controlling an opening degree of the branch pipe control valve.

Abstract: An interior permanent magnet type brushless direct current (BLDC) motor includes a stator having a plurality of slots and a stator coil wound on the slots. The interior permanent magnet type brushless direct current (BLDC) motor also includes a rotor that rotates with respect to the stator and that has a rotor core and a plurality of permanent magnets positioned in the rotor core. The rotor has a notch that is cut off between adjacent permanent magnets.

Abstract: A rotor of an electric motor includes lamination core formed by laminating a plurality of individual cores, and at least one pair of magnet members that generate rotating torque by electromagnetic interaction with a stator, are provided at the lamination core such that a magnetic sensor can sense magnetic flux, and have magnetic poles opposite to each other, such that a position of the rotor of the electric motor can be accurately detected and a process of manufacturing the electric motor can be simplified.

Abstract: A motor driver system includes an excess current sensing device configured to compensate a sensing value depending on a temperature of a motor, and to output the compensated sensing value, the sensing value being obtained from a current value associated with the motor; and a controller configured to stop the motor when the compensated sensing value exceeds a preset excess value.

Abstract: A synchronous reluctance motor comprises a stator and a rotor, the rotor comprising: a rotation shaft; a first core having a shaft hole for inserting the rotation shaft at a center thereof, and having a plurality of first flux barrier groups arranged along a circumferential direction of the shaft hole and spacing from each other; and a second core having a receiving hole larger than the shaft hole at a center thereof, and stacked at one side of the first core in an axial line direction. A length of the rotor protruding from a supporting portion can be decreased without reducing a stacked thickness thereof, and a vibration occurrence in a horizontal direction with respect to the rotation shaft can be reduced, thereby enhancing a reliability of the synchronous reluctance motor.

Abstract: A motor driver system and its control methods are discussed. Even when a command magnetic flux decreases as a motor operates in a field weakening region, a current angle can be maintained always below a limit value, thereby obtaining the stability of the motor control.

Abstract: A synchronous reluctance motor is described. The synchronous reluctance motor includes a core configured to rotate about a central axis and having first and second groups of flux barriers formed therein. Each flux barrier is defined as an opening in the core. Each of the first and second groups includes a first flux barrier and a second flux barrier with the second flux barrier disposed outside the first flux barrier in a radial direction from the central axis of the core. Each of the second flux barriers of the first and second groups has at least two connection parts crossing the opening of the second flux barrier.

Abstract: A motor driver system includes an inverter configured to apply a three-phase voltage to a motor; an inverter driver configured to generate a reference voltage to the inverter to control a motor speed to follow a reference speed; and a motor protector configured to control the inverter driver so that a value of the reference voltage is equal to or lower than a predetermined voltage value.

Abstract: An interior permanent magnet type brushless direct current (BLDG) motor includes a stator having a plurality of slots and a stator coil wound on the slots. The interior permanent magnet type brushless direct current (BLDC) motor also includes a rotor that rotates with respect to the stator and that has a rotor core and a plurality of permanent magnets positioned in the rotor core. The rotor has a notch that is cut off between adjacent permanent magnets.

Abstract: A rotor of a synchronous reluctance motor is provided. The rotor may include a laminated core including a plurality of laminated silicon steel sheets being equally divided into a plurality of regions with respect to a central portion of the plurality of silicon steel sheets. Each of the plurality of regions may include a plurality of barriers. Guide pin holes may be formed between adjacent regions so as to receive guide pins therethrough to align the plurality of silicon steel sheets and end caps provided at opposite ends thereof. Rivets may penetrate receiving holes formed at corresponding barriers in each of the respective regions so as to couple the laminated core and the end caps.

Abstract: A motor driver system includes an excess current sensing device configured to compensate a sensing value depending on a temperature of a motor, and to output the compensated sensing value, the sensing value being obtained from a current value associated with the motor; and a controller configured to stop the motor when the compensated sensing value exceeds a preset excess value.

Abstract: A rotor of a flux barrier type synchronous reluctance motor comprises: a rotation shaft; a rotor core formed as a plurality of steel plates are laminated to one another, the steel plate having a shaft hole for inserting the rotation shaft, a plurality of flux barrier groups spaced from one another in a circumferential direction and having a plurality of flux barriers spaced from one another in a radial direction, and a coupling hole penetratingly-formed between the adjacent two flux barrier groups; and a coupling member inserted into the coupling hole and fixing the steel plate. Accordingly, a fabrication cost and an entire weight of the motor are decreased, and a fabrication process is facilitated with a shortened fabrication time. Also, a large coupling intensity is obtained and a magnetic saturation does not occur, thereby preventing a function degradation of the motor.