Dual-Winding Voice Coil Motor Thrust Ripple Compensation
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Solution Overview
Problem
The existing servo drive control systems for voice coil motors in ultra-high precision servo control fields face challenges with thrust ripple in PWM power converter schemes, leading to reduced control performance and increased complexity, especially with high switching frequencies that increase costs and reduce stability.
Innovation Solution
A dual-winding voice coil motor structure is introduced, where secondary windings are added to compensate for the thrust ripple of main windings, using independent controlled voltage sources and H-shaped full-bridge drive circuits to synchronize the operation of main and secondary windings, thereby reducing thrust ripple and improving system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PWM power converter scheme is adopted to improve control flexibility and response speed, then control performance is improved, but thrust ripple increases and influences control precision
Solution Approach 1:
The patent converts the harmful thrust ripple generated by PWM switching into a compensatable signal. By detecting the ripple and using secondary windings to generate counteracting forces, the system transforms the PWM-induced disturbance into a controllable parameter that can be actively compensated, thereby maintaining both PWM benefits and control precision.
Solution Approach 2:
The patent introduces secondary windings as intermediary elements between the main windings and the load. These secondary windings generate compensating forces that mediate the harmful effects of PWM thrust ripple, allowing the system to enjoy PWM benefits while maintaining control precision through the intermediary compensation mechanism.
2Manufacturing precision
If switching frequency is increased to reduce thrust ripple, then thrust ripple is reduced to 5% of original, but switching loss increases 20 times and system cost increases
Solution Approach 1:
Instead of using high switching frequency to reduce thrust ripple (which causes high switching loss), the patent converts the thrust ripple itself into a useful signal for compensation. The secondary windings detect and compensate the ripple at the original low switching frequency, achieving thrust ripple reduction without the energy penalty of high-frequency switching.
Solution Approach 2:
The patent changes the approach parameter from switching frequency to winding configuration and control strategy. By maintaining low switching frequency but introducing secondary windings with compensating control, the system achieves thrust ripple reduction through parameter optimization rather than frequency increase, avoiding the associated energy losses.
3Manufacturing precision
If high switching frequency is used to reduce thrust ripple, then control performance is improved, but system stability is greatly reduced
Solution Approach 1:
The patent converts the harmful thrust ripple into a compensatable parameter rather than trying to eliminate it through high-frequency switching. This approach maintains system stability by working with the ripple signal constructively, using secondary windings to generate counteracting forces that stabilize the system while achieving smooth thrust output.
Solution Approach 2:
The patent uses periodic compensation action through secondary windings that operate in sync with the PWM switching cycle. By applying compensating forces at the same frequency and phase as the thrust ripple, the system achieves stable operation with reduced ripple without the instability caused by high-frequency switching.
4Stability of the object's composition
If linear power amplifier scheme is adopted to eliminate thrust ripple, then output thrust stability is improved, but current response has overshoot and the system cannot meet high overload and high acceleration requirements
Solution Approach 1:
The patent merges the advantages of both linear power amplifier and PWM schemes. The primary windings use PWM for high power and fast response, while secondary windings provide linear-like thrust ripple compensation. This combination achieves both high overload capability and smooth output thrust stability that neither scheme alone can provide.
Solution Approach 2:
The patent segments the drive system into primary windings for power delivery and secondary windings for precision control. This segmentation allows each subsystem to optimize for its specific function - primary windings handle high power PWM operation while secondary windings provide stable thrust compensation, achieving both high power and high stability simultaneously.
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 significantly reduces thrust ripple, enhances precision control, improves system stability, and decreases energy loss while lowering the cost of the drive controller, even at lower switching frequencies.
Implementation Method 1
The voice coil motor (VCM) is a motor designed according to Lorentz force theory and used for directly switching the electrical signal into the beeline displacement
Data Source
AI summary
A thrust compensation system of a dual-winding voice coil motor, which is used for driving the voice coil motor having secondary windings arranged between each pair of main windings, wherein the main windings are the main working windings of the voice coil motor and used for providing the output electromagnetic force required by the driving system of the voice coil motor; the secondary windings are compensation windings and used for providing the thrust ripple opposite to the main windings and compensating the thrust ripple of the main windings, so that the resultant force of the output thrust of the main windings and the secondary windings of the voice coil motor is constant. The scheme provided by this invention not only greatly reduces the thrust ripple of the servo system of the voice coil motor, but also realizes the ultra-high precision control of the servo drive system of the voice coil motor when the system is under low switching frequency, improves the stability of the system, reduces the system loss, and greatly reduces the cost of the drive controller.