Resonant Drive Circuit Phase Offset for Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resonant systems face challenges in maintaining stability due to component characteristics that drift with time, age, and temperature, affecting the control of resonant modes and efficiency in feedback control circuits.
Innovation Solution
A drive circuit with a feedback loop system that modifies the excitation signal amplitude and phase to maintain constant feedback signal amplitude, using a digital phase lock loop and automatic gain control, along with a drive amplitude reduction circuit employing a gradient descent algorithm to optimize the excitation signal phase and reduce amplitude, thereby stabilizing the resonant motion of a scanning mirror in a scanning laser projector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control circuit components are used to control resonant frequency, then resonant mode control is achieved, but component characteristics drift with time, age, and temperature causing instability
Solution Approach 1:
The patent employs a feedback control circuit that continuously monitors the resonant system's actual resonant frequency and adjusts the excitation signal accordingly. The feedback loop compares the actual frequency with the desired frequency and dynamically compensates for component drift, thereby maintaining stable resonant mode control despite changes in component characteristics over time or with temperature variations.
Solution Approach 2:
The system dynamically changes the parameters of the excitation signal (frequency, amplitude, or phase) based on real-time feedback from the resonant system. By continuously adjusting these parameters, the system compensates for component characteristic drift and maintains optimal resonant operation under varying conditions.
2Reliability
If excitation signal amplitude is increased to maintain resonant motion, then resonant frequency control is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of the excitation signal amplitude based on real-time feedback from the resonant system. Rather than using a fixed high amplitude, the system continuously adapts the amplitude to the minimum level required to maintain stable resonant motion, thereby reducing unnecessary power consumption while preserving control reliability.
Solution Approach 2:
The resonant system itself provides information about its state through the feedback signal, allowing the control circuit to automatically adjust the excitation amplitude. The system self-regulates by using the resonant response to determine the optimal drive level, eliminating the need for external intervention or conservative over-driving.
3Use of energy by moving object
If phase offset is used to reduce excitation signal amplitude, then power consumption decreases, but phase variations may affect resonant frequency and efficiency
Solution Approach 1:
The feedback control circuit monitors the resonant system's response and dynamically adjusts the phase offset to maintain optimal resonant operation. By continuously measuring the system's actual frequency and phase, the feedback loop compensates for any phase variations that might otherwise degrade performance, ensuring that power reduction does not compromise resonant frequency stability.
Solution Approach 2:
The system dynamically changes multiple parameters of the excitation signal (amplitude, phase, and frequency) in a coordinated manner based on feedback. By adjusting these parameters together rather than independently, the system achieves power reduction through optimized phase relationships while maintaining resonant frequency stability and overall system efficiency.
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 solution ensures a stable and efficient resonant motion of the scanning mirror, maintaining constant feedback signal amplitude and reducing power consumption, while minimizing the impact of phase variations on resonant frequency and efficiency.
Implementation Method 1
When trying to control a resonant system at a peak of a resonant mode
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A drive circuit (170) for a resonant system provides an excitation signal (173) having an amplitude (513) and a phase. The resonant system provides a feedback signal (175) representing an oscillation amplitude. The amplitude of the excitation signal is reduced for a substantially constant feedback signal amplitude by modifying the excitation signal phase.