Dual Spindle Motor Control Using BEMF for HDD Power Management
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Solution Overview
Problem
Current hard disk drive technology faces challenges in increasing areal density and power efficiency, particularly in high-capacity disk drives used in enterprise and cloud computing environments, where existing single spindle motor designs consume excessive power and lack fine control over disk stacks.
Innovation Solution
The implementation of dual spindle motors and dual spindle motor control systems, where each spindle motor controls a separate stack of disks, allowing for independent power management, reduced power consumption, and staggered spin-ups to minimize peak power usage, along with the use of a single Power Large Scale Integrated (PLSI) circuit to drive both motors, reducing component needs and die space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single spindle motor is used to control all disk stacks, then the device complexity is reduced, but the power consumption increases and fine control over individual disk stacks is lost
Solution Approach 1:
The patent divides the single spindle motor system into multiple independent spindle motors, with each motor controlling a specific stack of disks. This segmentation allows independent power management of each motor, enabling the system to activate only the motors needed for current operations, thereby reducing overall power consumption while maintaining control capability.
2Use of energy by moving object
If multiple spindle motors are implemented for fine control over disk stacks, then power efficiency improves, but the device complexity increases
Solution Approach 1:
The control system is designed to universally manage multiple spindle motors using a unified control architecture. The controller can selectively activate and manage different numbers of spindle motors based on operational requirements, making the system adaptable to various workload scenarios while maintaining efficient power management.
3Productivity
If all spindle motors spin up simultaneously to maximize data access capability, then the productivity increases, but the peak power consumption increases
Solution Approach 1:
The system implements staggered spin-up sequences where spindle motors are activated at different times rather than simultaneously. This periodic action allows the system to achieve the required data access capability by activating motors in stages, thereby reducing peak power consumption while still meeting productivity requirements.
4Quantity of substance
If disk stacks are arranged concentrically or coaxially to increase capacity, then the areal density improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent segments the disk stacks into separate groups, each controlled by its own dedicated spindle motor. This segmentation allows each motor to independently control its assigned stacks, reducing the cumulative impact of alignment variations and making the system more tolerant of manufacturing tolerances while maintaining high areal density.
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
This approach enhances areal density, reduces power consumption, and optimizes power usage by allowing one spindle motor to be in low-power mode when not in use, while maintaining high performance by controlling spindle speeds based on detected back electromotive force (BEMF) voltages, thereby improving overall disk drive efficiency and capacity.
Implementation Method 1
one or more processing devices configured to detect back electromotive force (BEMF) voltages generated by the first spindle motor and the second spindle motor
Data Source
AI summary
Various illustrative aspects are directed to a data storage device comprising a first spindle motor configured to rotate one or more disks in a first stack of disks, a second spindle motor configured to rotate one or more disks in a second stack of disks, and one or more processing devices configured to detect back electromotive force (BEMF) voltages generated by the first spindle motor and the second spindle motor. In other aspects the one or more processing devices can control speeds of the first spindle motor and the second spindle motor based on the detected BEMF voltages.