Marvell International Limited

Agency for Science, Technology and Research

Quan Jiang

Chao Bi

Song Lin

Mengjun Liu

Nay Lin Htun Aung

Hla Nu Phyu

Zhimin Yuan

Bo Liu

Li Wang

Siang Huei Leong

Chun Lian Ong

Weiya Xi

Khai Leong Yong

Jianzhong Shi

Kui Cai

Kheong Sann Chan

Pantelis Sophoclis Alexopoulos

Zhi Yong Ching

Qide Zhang

Budi Santoso

Jing Zhang

Moulay Rachid Elidrissi

Chiew Leong Wong

Zhimin He

Guchang Han

Tiejun Zhou

Ming Chou Lin

Jiang Feng Hu

Leonard Gonzaga

Ke Gan

Wuzhong Lin

Wee Kiat Lim

Sufui Sophia Tan

Yansheng Ma

Yin Quan Yu

Kannan Sundaravadivelu

Ningyu Liu

Jianqiang Mou

Boon Long Ibrahim See

Venkataramanan Venkatakrishnan

Song Ling

Cheng Peng Tan

Yin Qian Yu

Chong Wee Lee

Phyu Hla Nu

Wei Hua

Cheng Su Soh

Shengkai Yu

In various embodiments, a method of controlling a motor and motor control system may be provided. The method may include applying exciting pulse-width-modification (PWM) or continuous sinusoidal voltages to a motor. The method may further include measuring one or more the applied exciting voltages to the motor. The method may further include measuring one or more currents from the motor. The method may also include calculating one or more back electromotive force (BEMF) voltages based on the one or more currents. The method may include adjusting the exciting voltages based on the one or more back electromotive force (BEMF) voltages and the phase angle difference between the calculated back EMF voltages and the measured currents. The motor control system may include the various detecting circuits of the exciting voltages and the motor currents from the motor with low pass filters.

Motor control system and method of controlling a motor

A spindle motor for a hard disk drive includes a base and a bearing assembly coupled to the base. The bearing assembly includes a sleeve configured to rotatably support a shaft therein. A rotor hub is affixed to the shaft so as to be rotatable with the shaft about a rotational axis. A stator is arranged in between the rotor hub and the base. A first magnet is arranged over the stator and on a bottom surface of the rotor hub. In particular, the rotor hub includes a body portion, a peripheral wall portion extending from the body portion in a direction towards the base, and a flange portion having a disk seating surface configured for supporting one or more disks thereon. The peripheral wall portion is configured to at least partially surround the stator in a radial direction. There is also provided a method of fabricating the spindle motor and a hard disk drive incorporating the spindle motor.

Spindle motor for hard disk drive and method of fabrication thereof

According to an embodiment of the present invention, a data storage device comprising a motor having a stator is disclosed. The stator may include a substrate having a first surface and a second surface opposite to the first surface; and a n-phase winding arrangement having n phase windings; wherein each phase winding comprises m flat fractional-pitch coils arranged on the first surface of the substrate such that the coils are spaced apart uniformly along a closed loop and connected in series; wherein each coil together with an angular section of the substrate between the coil and an adjacent coil of the same phase winding defines a stator pole-pair; and wherein m is an integer larger than 1.

Data storage device

A magnetic disk drive device for rotary driving a magnetic disk may be provided. The magnetic disk drive device may include a drive motor for rotary driving the magnetic disk. The drive motor may include a motor hub which has motor hub support portion with a screw-type motor hub engaging portion, and a motor hub support surface for supporting the magnetic disk. The magnetic disk drive device may also include a clamp disk including a clamp disk support portion with a screw-type clamp disk engaging portion complementary to the motor hub engaging portion, and a clamp disk support surface for supporting the magnetic disk.

Magnetic disk drive device, magnetic disk assembly and methods of forming the same

A low profile spindle motor for supporting and rotating media disk or disks of a hard disk drive includes a plurality of stator teeth, a winding layer which may be formed by printed circuit board or the like, and a rotor. The plurality of stator teeth are disposed in an annular region surrounding an axis of rotation of the motor, and have projected ends for increasing the tooth area facing a magnet ring of the rotor. The winding layer has a plurality of windings disposed surrounding the axis of rotation. Each winding is coupled to one of the plurality of stator teeth. The magnet ring is positioned radially spaced apart and coplanar with the annular region. The magnet ring has magnetic poles annularly distributed to generate magnetic fluxes along radial direction. Spindle motor formed according to the invention has a low profile, improved performance and manufacturability.

Low profile spindle motor

A runout measurement system is proposed for measuring the runout of a moving surface of a device having a rotating body, such as a mass storage device () (e.g. a hard disk drive) having a rotor which in use includes a rotating recording medium. A sensor () interacting with the moving surface obtains a displacement signal. The displacement signal is sampled by a sampling unit () controlled by a unit () which initiates sampling based on both a signal indicating a ZCP and the clock signal of a high frequency (e.g. 20 MHz) clock (). Simultaneously, the same clock () is used by a counterto measure the spacing between one or more ZCP times. This permits the correspondence between the sampling times and the angular position of the rotor to be found with a high accuracy which depends upon the clock frequency, and thereby allows calculation of repeatable runout (RRO) and non-repeatable runout (NRRO).

Runout measurement for devices having a rotating body

A low profile permanent magnet synchronous motor with segment structure. In accordance with this invention, a stator assembly for an electromagnetic motor is provided. The stator assembly has a first stator core and a second stator core that couple windings. Teeth extend outward from each stator core and through the windings to contact the other stator core.

Low profile permanent magnet synchronous motor with segment structure

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Singapore, Singapore

Quan Jiang