Modular Resonant Converter for Electrostatic Precipitator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resonant converters for high-voltage DC applications, such as electrostatic precipitators, face inefficiencies due to optimized performance at a single operating point, poor load sharing in modular designs, and increased conduction losses from circulating currents and quasi-sinusoidal waveforms, which limit their scalability and power handling capability.
Innovation Solution
The implementation of a modular series loaded resonant converter system where multiple units share a common resonant tank, with a series loaded resonant tank comprising a capacitor connected directly to the transformer's primary winding and individual inductors for each unit, to maintain equal load sharing and prevent circulating currents, allowing for scalable and efficient power handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resonant converters are optimized for a single operating point, then switching losses are minimized, but performance degrades with wide range input voltage and load power variations
Solution Approach 1:
The resonant tank is divided into multiple segments, each with its own switching unit (e.g., H-bridge circuits). Each segment can be independently controlled and switched on or off based on load requirements. This segmentation allows the converter to maintain optimal resonance conditions for active segments while adapting to varying power demands, thus resolving the contradiction between minimizing switching losses and maintaining adaptability across wide operating ranges.
Solution Approach 2:
The converter employs dynamic control of switching frequencies and duty cycles for each segment. The switching frequency can be dynamically adjusted to track the resonant frequency of the tank, while the duty cycle modulates power delivery. This dynamic adaptation allows the system to maintain optimal performance across varying input voltages and load conditions, resolving the contradiction between fixed-point optimization and wide-range versatility.
2Power
If modularizing is used to increase power handling capability, then scalability is improved, but load sharing among modules becomes difficult to control
Solution Approach 1:
The system incorporates feedback control mechanisms that monitor the output current and voltage of each modular segment. Based on this feedback, the control system adjusts the switching parameters of each module to achieve balanced load sharing. This feedback control simplifies the complexity of coordinating multiple modules while enabling scalable power handling, as each module automatically adapts its contribution based on real-time system conditions.
Solution Approach 2:
Each modular segment is designed with self-regulating characteristics where the resonant tank naturally distributes current among active modules. The segments autonomously adjust their switching patterns based on local conditions and overall system state, reducing the need for complex centralized control. This self-service approach enables easy scalability while maintaining simple load sharing, as modules naturally balance their contributions without intricate coordination protocols.
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 approach ensures equal load sharing among modules, reduces circulating currents, and maintains efficiency across a range of input voltages and load powers, enhancing the converter's scalability and power handling capabilities while minimizing switching losses.
Implementation Method 1
The resonant tank 9 comprises an inductor 16 and a capacitor 17 in series and together with the primary winding 18 these elements are basically defining the resonance frequency of the resonant tank
Implementation Method 2
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)
Implementation Method 3
The three phase mains with the three phases 1-3 which can be individually switched by switches 4, is rectified by a six-pulse rectifier 6 e.g. comprising diodes 5
Data Source
Figure 1
Figure 2~2b
Figure 3
AI summary
The disclosure pertains to a high-voltage AC-DC converter converting alternating input current (1-3) into high-voltage direct current to be provided to a load (12), e.g. for use of powering an electrostatic precipitator. Said converter comprises a unit (22) for the conversion of the alternating (AC) input current into high frequency alternating (AC) current, at least one transformer (10) for adapting the high frequency alternating (AC) current to requirements of the load (12), wherein between said unit (22) and said transformer (10) there is provided a series loaded resonant tank. Modularizing of the topology is achieved in that there are at least two units (22) for the conversion of the alternating (AC) input current into high frequency alternating (AC) current connected to the same transformer (10).