Ballast Transformer Segmentation for Discharge Lamp Ignition
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Solution Overview
Problem
Current ballasts for discharge lamps in vehicles are bulky due to high transformation ratios, leading to significant leakage elements and overvoltages, and require costly diodes for 1000V rectification, which complicates production and increases costs.
Innovation Solution
A ballast design incorporating a transformer with a main winding, secondary winding, and auxiliary winding, combined with a voltage multiplier circuit using two capacitors and diodes, reduces transformation ratios and eliminates the need for high-voltage diodes, allowing for efficient generation of ignition voltage with lower component stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a high transformation ratio transformer is used to generate high voltage for discharge lamp ignition, then the ignition voltage is sufficient, but the transformer volume becomes very large and leakage elements increase significantly
Solution Approach 1:
The patent divides the voltage multiplication function into multiple stages using a cascade connected structure. Instead of using a single transformer with high transformation ratio, the invention employs multiple transformers with lower transformation ratios connected in cascade, where each stage contributes to the overall voltage multiplication. This segmentation reduces the volume of individual transformers while achieving the required high ignition voltage through cumulative effect.
Solution Approach 2:
The patent transitions from a single-stage voltage transformation approach to a multi-stage cascade configuration. By adding the dimension of multiple stages connected in series, the system achieves high voltage output without requiring any single transformer to have excessive transformation ratio, thus avoiding the volume and leakage problems associated with high-ratio transformers.
2Stress or pressure
If a high transformation ratio transformer is used to create sufficient ignition voltage, then the lamp can be ignited, but significant leakage elements cause overvoltages in the switching unit and interfere with DC/DC converter control
Solution Approach 1:
By segmenting the voltage multiplication into multiple low-ratio transformer stages, the patent reduces leakage inductance in each stage. This segmentation prevents the accumulation of significant leakage elements that would otherwise cause overvoltages and control interference in the DC/DC converter, while still achieving the required ignition voltage through the cascade connection.
3Stress or pressure
If rectifier diodes are dimensioned for 1000V to handle the high voltage from the transformer, then adequate voltage handling is achieved, but production problems and costs increase
Solution Approach 1:
The patent segments the voltage stress across multiple lower-voltage diodes in the cascade configuration. Each diode in the multi-stage system handles a portion of the total voltage rather than the full 1000V, allowing the use of standard, readily available diodes with lower voltage ratings. This significantly improves ease of manufacture and reduces costs compared to using specialized 1000V-rated diodes.
4Stress or pressure
If a transformer with more than 20 turns in secondary windings is used to achieve the required voltage, then ignition voltage is obtained, but the transformer occupies very large volume
Solution Approach 1:
The patent applies segmentation by dividing the total voltage multiplication requirement into multiple stages, each with fewer turns in the secondary windings. Instead of one transformer with 20+ turns, the cascade configuration uses multiple transformers with fewer turns each, reducing the volume of individual components while achieving the same overall voltage transformation through series connection.
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 design reduces the overall volume of the transformer, minimizes leakage elements, and uses standard diode sizing, enhancing reliability, reducing costs, and ensuring reliable ignition of discharge lamps with lower component stress and improved electromagnetic compatibility.
Implementation Method 1
The repetitive interruption of the latter by the switching unit induces at the terminals of the two secondary windings of the transformer respectively two high voltages
Implementation Method 2
each rectifier comprising a diode and a capacitor. The repetitive interruption of the latter by the switching unit induces at the terminals of the two secondary windings of the transformer respectively two high voltages each rectified by the diode
Implementation Method 3
each rectifier comprising a diode and a capacitor. The repetitive interruption of the latter by the switching unit induces at the terminals of the two secondary windings of the transformer respectively two high voltages each rectified by the diode and filtered by the capacitor
Data Source
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AI summary
The ballast (BLST) has a direct current/direct current (DC/DC) voltage converter (Ccc) for supplying a rectified DC voltage (Vout) and including a transformer (TR1) that has main, secondary and auxiliary windings (n1-n3). The transformer supplies the rectified voltage. A voltage multiplier circuit (MU) of the converter supplies an ignition voltage (Vignit), where a voltage difference between the ignition and rectified voltages creates a starting voltage for a discharge lamp (LA).