Spindle Motor Power Generation via Phase and Amplitude Control
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Solution Overview
Problem
Existing data storage devices face challenges in efficiently converting the spindle motor into a power generator during power failures, as they rely on back electromotive force (BEMF) voltage for commutation and power assistance, which is not optimal for maximizing power generation.
Innovation Solution
The spindle motor is configured into a power generator by adjusting the phase and amplitude of the periodic driving voltage to ensure the current flowing through its windings is substantially opposite in phase from the sinusoidal BEMF voltage, allowing for efficient power generation during power failures, such as when the supply voltage falls below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spindle motor uses BEMF voltage for commutation and power assistance during power failure, then the motor can operate without external power, but the power generation efficiency is not maximized
Solution Approach 1:
The patent changes the operating parameters of the spindle motor by adjusting the phase and amplitude of the driving voltage applied to the windings. Specifically, it sets the driving voltage phase to be substantially opposite to the BEMF voltage phase, which transforms the motor into an efficient power generator mode. This parameter adjustment allows the motor to maximize power generation while maintaining reliability during power failures.
2Power
If the phase and amplitude of driving voltage are adjusted to maximize power generation, then power generation efficiency increases, but the control complexity increases
Solution Approach 1:
The patent employs feedback control by detecting the BEMF voltage generated by the spindle motor and using this information to adjust the phase and amplitude of the driving voltage. The control circuit monitors the BEMF signal and automatically adjusts the driving parameters to maintain optimal power generation conditions, thereby managing control complexity through intelligent feedback mechanisms.
Solution Approach 2:
The spindle motor system uses its own BEMF voltage output to control its own operation during power failure. The BEMF signal generated by the motor's rotation is fed back to the control circuit, which then adjusts the driving voltage parameters accordingly. This self-service approach allows the system to maximize power generation without requiring complex external control systems.
3Reliability
If the spindle motor operates in generator mode during power failure, then it can sustain critical operations, but the supply voltage may drop below target level
Solution Approach 1:
The control circuit continuously monitors the supply voltage level and uses this feedback to adjust the driving voltage parameters applied to the spindle motor windings. When the supply voltage drops below the target level, the control circuit modifies the phase and amplitude of the driving voltage to increase power generation, thereby maintaining the supply voltage at the required level for critical operations.
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 configuration maximizes the power generated by the spindle motor, enabling it to sustain critical operations like completing write operations and unloading the head, while maintaining the supply voltage at a target level, thus ensuring reliable power down operations.
Implementation Method 1
measuring a zero-crossing frequency of a back electromotive force (BEMF) voltage generated by the windings of the spindle motor
Implementation Method 2
a periodic current flowing through each winding is substantially opposite in phase from a sinusoidal back electromotive force (BEMF) voltage generated by each winding
Data Source
AI summary
A data storage device is disclosed comprising a disk, a spindle motor configured to rotate the disk, wherein the spindle motor comprises a plurality of windings, and a head actuated over the disk. The windings of the spindle motor are commutated based on a commutation sequence while applying a periodic driving voltage to each winding, wherein the periodic driving voltage comprises an operating amplitude during normal operation. When a supply voltage falls below a threshold, the spindle motor is configured into a power generator by at least adjusting the amplitude and a phase of the periodic driving voltage so that a periodic current flowing through each winding is substantially opposite in phase from a sinusoidal back electromotive force (BEMF) voltage generated by each winding.