Kabushiki Kaisha Toshiba

Shigen Yasunaka

Shinji Takakura

Yoshiyuki Ishihara

Satoshi Kuwahara

According to one embodiment, an inverter device configured to be capable of switching an on or off state of each of a plurality of switching elements, on the basis of a control command signal, and operable as a single-phase inverter, includes: a pulse width modulator configured to set a voltage value at a time when one of the switching elements is set to the on state to a first voltage, and set a voltage value at a time when the other three of the switching elements are set to the on state to a second voltage larger than the first voltage, in operation as the single-phase inverter; and a detection unit configured to detect the control command signal in operation as the single-phase inverter.

Inverter device and method for detecting heat dissipation characteristics of inverter device

According to an embodiment, an inspection apparatus inspects an inverter circuit including three pairs of arms. The apparatus includes a current controller and a control signal generator. The current controller generates a control output for controlling a current to be output by the inverter circuit. The control output enables the current to approach a target value of the current. The control signal generator generates a first control signal for controlling ON/OFF of a first arm as one of the three pairs of arms based on the control output, a second control signal for fixing a second arm paired with the first arm, in an OFF-state, and a third control signal for fixing at least part of arms other than the first arm and the second arm in an ON-state.

Inspection apparatus, inspection method, and inverter apparatus

According to one embodiment, a correction device is used for an apparatus including a coil and a conductor in a vicinity of the coil. The correction device corrects an influence of a magnetic field generated by the conductor when a current flows through the coil. The correction device includes a first measuring device, a second measuring device, and a control device. The first measuring device measures a first signal of the coil. The second measuring device measures a second signal of the coil, which is different from the first signal. The control device estimates the influence acting on the coil, based on a difference between the first signal filtered by a first filter and the second signal filtered by a second filter. Furthermore, the control device controls a command signal for flowing the current to the coil, based on an estimation result of the influence.

Correction device, correction method, and magnetic resonance imaging apparatus

According to one embodiment, a servo write control apparatus is for a disk apparatus including a read element and a write element located in an outer side of a disk from the read element. The servo write control apparatus detects a plurality of first burst signals recorded in a circumferential direction of the disk by the read element. The servo write control apparatus calculates an offset in a radial direction when the write element writes a second burst signal, based on amplitude values of at least two of the first burst signals used for positioning the read element. The servo write control apparatus adjusts a write position of the second burst signal based on the offset.

Servo write control apparatus and method, and magnetic disk apparatus

According to one embodiment, a hard disk drive includes a head, a voice coil motor, a driving circuit, an identification unit, a storage unit, and an estimation unit. The head is configured to perform write/read of information to a storage medium. The voice coil motor is configured to move the head. The driving circuit is configured to drive the voice coil motor, based on a command signal. The identification unit is configured to identify at least one parameter of a discrete-time model. The discrete-time model represents a transfer function from the command signal to a voltage drop quantity by an inductance of a coil of the voice coil motor. The storage unit is configured to store the parameter. The estimation unit is configured to estimate a back electromotive force of the coil, based on the discrete-time model including the parameter.

Hard disk drive, method for estimating back electromotive force, and method for controlling velocity of head

According to one embodiment, an estimation method comprises measuring and creating. The measuring is configured to measure a head velocity and a terminal voltage of a coil of a voice coil motor at least two times before unload in a control system eliminating an influence caused by a transient response of inductance of the voice coil motor. The calculating is configured to a calculate torque constant and a coil resistance based on command voltages and at least two measured head velocities and terminal voltages of the coil.

Growing community of inventors

Tokyo, Japan

Shigen Yasunaka