Spindle Motor Speed Control for Rotating Storage Power Reduction

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Solution Overview

Problem

Conventional rotating storage devices face high power consumption and latency issues due to constant spindle motor operation and shutdown processes, particularly in portable devices where power efficiency and quick data access are critical.

Innovation Solution

A speed control system that dynamically manages the operational speed of rotating storage devices by selecting between operating, standby, and shutdown modes based on usage, reducing power consumption while minimizing latency through predetermined speed settings and using back electromotive force (bemf) for spindle motor speed monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the spindle motor maintains constant operating speed, then data access speed is improved, but power consumption increases

Engineering Contradiction:

Improvedata access speedVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The spindle motor speed is made dynamic rather than constant. The system transitions between multiple speed states (operating speed for data access, standby speed for low-power idle state, and shutdown mode for complete stop) based on usage patterns, allowing the motor to adapt its rotation speed to actual needs rather than maintaining constant high-speed operation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements periodic speed changes based on inactivity detection. After a predetermined period of no data access operations, the spindle motor automatically reduces speed to standby level or shuts down, and quickly restarts when data access is needed again, creating a periodic cycle between high-performance and low-power states

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If the spindle motor shuts down completely, then power consumption is reduced, but access latency increases

Engineering Contradiction:

Improvepower consumptionVSAvoidaccess latency

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The system performs preliminary action by maintaining the spindle motor at a reduced standby speed (greater than zero) after a first predetermined inactivity period, rather than shutting down completely. This preliminary partial operation prepares the motor for quick resumption of full operation when data access is needed, reducing the spin-up time and associated latency while still achieving significant power savings compared to constant high-speed operation

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the spindle motor operates at high speed continuously, then data access performance is maintained, but power consumption increases

Engineering Contradiction:

Improvedata access performanceVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The system changes the operational parameters of the spindle motor based on usage conditions. Instead of operating at a single fixed high speed, the motor operates at different speed parameters (high operating speed for active data access, reduced standby speed for idle periods, and zero for shutdown) depending on whether data access is currently needed, thereby optimizing the balance between performance and power consumption

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system effectively reduces power consumption and latency by transitioning to lower standby speeds during inactivity and quickly returning to operational speeds upon demand, enhancing the performance and efficiency of rotating storage devices in portable devices.

Implementation Method 1

The speed monitoring module determines a speed of the rotating storage device based on back electromotive force (bemf) of a spindle motor that rotates the rotating storage device

Methodology Applied

Scientific EffectBack electromotive force (bemf): Electromagnetic Induction

Data Source

PatentUS8638519B1Speed control systems and methods for decreasing power consumption in rotating storage devices

Publication Date: 2014.01.28 MARVELL ASIA PTE LTD

AI summary

A system including a monitoring module configured to monitor whether, during a first predetermined period, at least one of a read operation, a write operation, or a seek operation is performed on a platter of a storage device in response to the platter of the storage device rotating at a first speed. A speed control module is configured to rotate the platter of the storage device at a second speed in response to none of the read operation, the write operation, or the seek operation being performed on the platter of the storage device during the first predetermined period. The second speed is (i) less than the first speed, and (ii) greater than zero. None of the read operation, the write operation, or the seek operation is performed on the platter of the storage device in response to the platter of the storage device rotating at the second speed.