Modular High-Voltage AC-DC Converter for Electrostatic Precipitators
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Solution Overview
Problem
High-voltage DC power supplies for electrostatic precipitators face challenges in scalability, fault tolerance, and efficiency due to high-frequency operations leading to partial discharges and increased stress on transformer components, particularly in modular designs where load sharing and magnetic coupling issues arise.
Innovation Solution
A high-voltage AC-DC converter with multiple secondary windings and individual magnetic cores, each connected to a high-voltage rectifier, allowing for modular scalability and reduced magnetic coupling, increasing fault tolerance and efficiency by minimizing material usage and stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single secondary transformer winding is used, then the structure is simple, but the fault tolerance and scalability are limited
Solution Approach 1:
The patent divides the single secondary winding into multiple secondary windings (at least two), where each winding is connected to a separate high-voltage rectifier. This segmentation allows the system to maintain functionality even if one winding or rectifier fails, thereby improving fault tolerance while managing complexity through modular design
2Power
If modular design is implemented for scalability, then the power handling capability increases, but the load sharing control and magnetic coupling issues arise
Solution Approach 1:
The patent implements modular design by providing at least two secondary windings with individually associated high-voltage rectifiers, allowing independent scaling of power capacity. Each module (winding + rectifier) can be added or removed to scale power handling capability without affecting other modules, simplifying load sharing through natural independence
Solution Approach 2:
The patent reduces magnetic coupling issues by arranging secondary windings in spatial separation (different dimensions), where each secondary winding is wound around its own magnetic core or positioned to minimize mutual inductance. This dimensional separation allows modular scaling while minimizing unwanted magnetic interactions between modules
3Volume of moving object
If high-frequency operation is used, then the transformer size is reduced and power density increases, but partial discharges and component stress increase
Solution Approach 1:
The patent divides the high-voltage output into multiple secondary windings, each with its own rectifier, thereby segmenting the high-frequency AC fields. This segmentation reduces the voltage stress and partial discharge activity in each individual winding compared to a single high-voltage winding, while maintaining the compact high-frequency transformer design
Solution Approach 2:
The patent introduces individual high-voltage rectifiers as intermediary components between each secondary winding and the load. These rectifiers convert high-frequency AC to DC at lower voltage levels before combination, reducing the high-frequency AC stress and partial discharge risks in the transformer windings while maintaining efficient power transfer
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 enhances the fault tolerance and efficiency of high-voltage power conversion systems, reducing material needs and component stress, leading to a more cost-effective and compact design capable of handling higher power with reduced operational losses.
Implementation Method 1
The transformer 10, consisting of the primary winding 18 and the secondary winding 19, adapts the input voltage (mains) to the load 12 (ESP, 50-150kV). The secondary alternating voltage of the transformer 10 is rectified by a high voltage rectifier 11 and fed to the load 12.
Implementation Method 2
The output of the bridge 8 (high frequency AC voltage) is connected, via a resonant tank 9, to the primary of a transformer 10. The resonant tank 9 comprises an inductor 16 and a capacitor 17 in series and together with the primary winding 18 these elements basically define the resonance frequency of the resonant tank, which correspondingly can only reasonably be operated around this resonance frequency.
Implementation Method 3
The secondary alternating voltage of the transformer 10 is rectified by a high voltage rectifier 11 and fed to the load 12.
Data Source
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AI summary
The disclosure pertains to a high-voltage AC-DC converter converting alternating current (1-3) into high-voltage direct current to be provided to a load (12), e.g. for use as an electrostatic precipitator. The converter comprises at least one transformer (10), wherein the transformer comprises at least one primary winding (18, 22-25) on the AC-side and at least two secondary windings (27) on the DC-side. The converter further comprises at least one rectifier (6) rectifying alternating input current, comprising at least one transistor bridge (8) converting the resulting direct current into alternating current, the transformer (10) transforming the resulting alternating current, and comprising at least two high-voltage rectifiers (11, 29) connected to each of the secondary windings (27), wherein the output voltage of the high-voltage rectifiers (11, 29) is connected in series.