18-Pulse ATRU Balancing Resistor Control Across Wide Frequency Range
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Solution Overview
Problem
Existing auto-transformer rectifier unit (ATRU) systems, particularly in aircraft, face challenges in maintaining optimal power flow balance across a wide frequency range due to fixed balancing resistors, leading to inefficiencies and increased harmonic distortion.
Innovation Solution
A self-adjusting balancing resistor system that uses a controller to dynamically adjust resistance based on measured output current imbalances or changes in input frequency, ensuring equal power flow through all diode bridge rectifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed balancing resistor is used in the ATRU system, then the power flow balance is optimized at a specific frequency (around 600 Hz), but the power flow balance deteriorates when operating at other frequencies within the 360 Hz to 800 Hz range
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed balancing resistor with a dynamically adjustable resistor whose resistance value changes based on the operating frequency. The controller receives frequency signals from the ATRU system and automatically adjusts the resistor value to maintain optimal power flow balance across the entire 360 Hz to 800 Hz frequency range, transforming a static component into a dynamic adaptive element.
Solution Approach 2:
The patent implements feedback by using the controller to monitor the operating frequency of the ATRU system and adjust the balancing resistor accordingly. The controller receives frequency information and provides feedback control to maintain balanced power flow through all diode bridge rectifiers, creating a closed-loop control system that adapts to frequency variations.
2Adaptability or versatility
If the ATRU system operates across a wide frequency range (360 Hz to 800 Hz), then the system versatility is improved, but maintaining optimal power flow balance becomes more difficult with a fixed resistor value
Solution Approach 1:
The patent applies parameter changes by varying the resistance value of the balancing resistor according to the operating frequency. The controller adjusts the resistor parameter (resistance value) to compensate for frequency changes, ensuring that the power flow balance is maintained across the entire 360 Hz to 800 Hz range. This dynamic parameter adjustment resolves the conflict between wide frequency operation and reliable power flow balance.
3Object-generated harmful factors
If an 18-pulse converter configuration is used, then harmonic distortion is reduced further, but power flow imbalance occurs between the three phases with a fixed balancing resistor
Solution Approach 1:
The patent applies dynamics by making the balancing resistor adjustable rather than fixed, allowing it to adapt to the specific requirements of the 18-pulse converter configuration across different frequencies. This dynamic adjustment ensures that all three phases maintain balanced power flow while benefiting from the reduced harmonic distortion characteristics of the 18-pulse system.
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 solution maintains balanced power flow across a broader frequency range, reducing power losses and improving power quality, thereby minimizing the need for additional filtering and simplifying system design.
Implementation Method 1
a balancing resistor is usually provided to the bypass bridge
Data Source
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Figure 5
AI summary
An auto-transformer rectifier system comprising an 18-pulse (or multiple of 18-pulse) autotransformer rectifier unit ATRU having three, or a multiple of three, diode bridge rectifiers (5a, 5b, 5c) and a balancing resistor (40) to balance the power flow through the diode bridge rectifiers, wherein the balancing resistor has a variable resistance, and further comprising a controller (80) configured to identify imbalances between power flows of the respective diode bridge rectifiers and to adjust the resistance of the balancing resistor in response to the detected imbalance.