Direct Drive Power Control via Impedance Synthesizer
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Solution Overview
Problem
Direct drive power control systems face challenges in managing power delivery stability, especially with nonlinear loads like LED lighting, due to voltage fluctuations from the utility grid, which can lead to damage or operational issues, and require efficient and cost-effective solutions for impedance control and protection.
Innovation Solution
The implementation of a voltage-controlled impedance synthesizer combined with pulse-width-modulation (PWM) techniques to control impedance and duty cycle, allowing for fine-tuned power delivery and protection mechanisms, including over-voltage and over-current protection, while reducing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If direct drive is used to eliminate power conversion components, then energy efficiency is improved and cost is reduced, but stability of power supply voltage becomes uncertain and load may be damaged by voltage fluctuations
Solution Approach 1:
The patent introduces an intermediary control system between the power supply and the load. This control system includes voltage detection means, current detection means, and control means that adjusts switching element duty cycles based on detected voltage and current levels. The intermediary controller manages the direct drive connection to prevent damage from voltage fluctuations while maintaining the efficiency benefits of direct drive architecture.
2Device complexity
If direct drive is used without galvanic isolation, then system cost is reduced and EMI is minimized, but protection against voltage fluctuations and over-current conditions becomes more difficult
Solution Approach 1:
The patent implements feedback control by continuously detecting voltage and current levels and using this information to adjust the switching element duty cycles. The control means responds to detected voltage fluctuations and current conditions by modifying switch operation, providing real-time protection without requiring complex isolation components. This feedback mechanism maintains safety while preserving the cost advantages of direct drive.
Solution Approach 2:
The control system provides self-protection capabilities by automatically detecting harmful conditions and adjusting its operation accordingly. The system monitors its own operating parameters and takes corrective action through duty cycle adjustment, eliminating the need for external protection circuits or complex isolation hardware while maintaining protection against voltage and current anomalies.
Data Source
AI summary
A power control circuit comprising a power supply and a load, the load being synthesized from an impedance synthesizer comprising two-terminal impedance elements connected in series and grouped in impedance modules. The impedance elements in each impedance module are of equal value, while those between the modules bear ratios uniquely defined according to the numbers of impedance elements in the impedance modules. A number of switches associated with said impedance elements short out a selected number of the impedance elements under the control of a first analog signal which may be preprocessed by an analytic function. The analog signal is converted to digital signals by an analog-to-digital converter, then level shifted to control the switches associated with the impedance elements, whereby the amount of power delivered to the load is controllable by the first analog signal. Pulse-width-modulation is deployed to further control the power by a second analog signal, with additional benefit of overload protection.