Transformer Rectifier Control for Stable LED DC Distribution
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Solution Overview
Problem
Existing power distribution systems face challenges in providing stable direct current to LED loads, particularly in maintaining efficiency and stability against impedance changes, and in controlling the level of direct current without producing unsuitable voltage harmonics.
Innovation Solution
The system employs a rectifier connected to a transformer's secondary winding, with capacitors providing reactance to compensate for the primary winding's reactance and a switch to control the direct current level, using field-effect transistors controlled by a further secondary winding to manage voltage and current efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rectifier is connected to a transformer's secondary winding to provide direct current to LED loads, then power distribution is achieved, but stability against impedance changes and efficiency are compromised
Solution Approach 1:
The patent applies parameter changes by introducing capacitors that provide reactance to compensate for the primary winding's reactance. This changes the electrical parameters of the circuit to achieve both stability against impedance changes and improved rectifier efficiency. The capacitors modify the reactance parameters to create a compensated system that maintains performance under varying load conditions.
2Ease of operation
If a switch is used to control the level of direct current, then current control is achieved, but voltage harmonics are produced in the cable
Solution Approach 1:
The patent uses an intermediary approach by introducing a switch that is controlled by a further secondary winding. This intermediary control mechanism allows for smooth current regulation without the abrupt switching that causes voltage harmonics. The further secondary winding acts as a mediator to provide controlled gating signals that prevent harmful harmonic generation while maintaining current control capability.
Solution Approach 2:
The patent replaces mechanical or direct switching mechanisms with a field-effect transistor-based switching system controlled by electromagnetic induction from a further secondary winding. This substitution eliminates the harsh electrical transients associated with conventional switching, thereby controlling direct current levels without producing unsuitable voltage harmonics in the cable.
3Use of energy by moving object
If field-effect transistors are controlled by a further secondary winding to manage voltage and current, then efficiency is improved, but device complexity increases
Solution Approach 1:
The further secondary winding serves multiple functions: it controls the field-effect transistors for efficient voltage and current management, and simultaneously provides the gating signals needed for synchronized operation. This multi-functionality reduces the need for separate control circuits, thereby improving energy efficiency while limiting the increase in device complexity.
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 enhances the stability and efficiency of direct current supply to LED loads, allows for controlled direct current levels without voltage harmonics, and provides cost-effective and energy-efficient power distribution.
Implementation Method 1
a rectifier operatively connectable to a secondary winding of a transformer whose primary winding is for carrying a high-frequency alternating current
Implementation Method 2
a first capacitor operatively connectable to the secondary winding; and a second capacitor operatively connectable, at least partly via the rectifier, to the secondary winding, wherein the first and second capacitors together provide a reactance referred to the primary winding which substantially compensates for the reactance of the primary winding
Implementation Method 3
a rectifier operatively connectable to a secondary winding of a transformer
Implementation Method 4
The apparatus may comprise an inductor configured to smooth a current originating from the rectifier
Implementation Method 5
a switch configured to periodically interrupt a current originating from the rectifier, thereby reducing an average level of the direct current provided to the load
Implementation Method 6
The rectifier comprises field-effect transistors controlled by a further secondary winding of the transformer
Data Source
Figure 1~2
Figure 3a~4
Figure 5~6
AI summary
Several aspects of power distribution systems are described. One aspect relates to apparatus for providing a direct current to a load at first and second main outputs. The apparatus comprises: a synchronous rectifier operatively connectable to a secondary winding of a transformer whose primary winding is for carrying high-frequency alternating current, the synchronous rectifier having first and second outputs, wherein the synchronous rectifier comprises first and second switches and a control circuit comprising: a further secondary winding of the transformer, a control port configured to control the first and second switches of the synchronous rectifier and thereby to turn the synchronous rectifier on and off, and a subcircuitry configured to provide a voltage to the control port. The first and second rectifier outputs are directly connected to the first and second main outputs respectively. The subcircuitry is connected to the first and second main outputs.