IGBT Rectifier Control for Ultra-Capacitor Inrush Current
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Solution Overview
Problem
Existing rectifiers for charging capacitors, such as diode bridge and Thyristor rectifiers, suffer from high current harmonics, total harmonic distortion, high acoustic noise, and low power factor, while IGBTs fail due to short circuit conditions when charging capacitors with zero charge, and pre-charge resistors are impractical for large capacitor banks.
Innovation Solution
A system using IGBTs controlled by a controller to charge ultra-capacitors, with a power converter, diode bridge rectifier, and current sensors to manage current flow, reducing harmonics and noise, and preventing overcurrent and overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional rectifiers (diode bridge or Thyristor) are used to charge capacitors, then the rectification function is achieved, but high current harmonics and total harmonic distortion (THD) are generated
Solution Approach 1:
The patent changes the operating parameters of the rectifier by using IGBTs with pulse-width modulation (PWM) control instead of traditional diode or Thyristor configurations. This allows precise control of switching timing and duty cycle, transforming the rectification process to minimize harmonic generation while maintaining effective capacitor charging functionality.
2Object-generated harmful factors
If traditional rectifiers are used, then rectification is achieved, but high acoustic noise levels are produced
Solution Approach 1:
The patent reduces acoustic noise by changing the switching parameters and operating frequency of the rectifier circuit. Using IGBTs with optimized PWM switching reduces mechanical vibrations and electromagnetic noise compared to traditional rectifiers, creating a quieter operational environment while maintaining rectification performance.
3Speed
If IGBTs are used to charge capacitors with zero charge, then fast charging is achieved, but the IGBT immediately overheats and fails due to infinite current rise
Solution Approach 1:
The patent implements preliminary protective actions by incorporating pre-charge resistors and current limiting circuits that activate before the main IGBT charging phase. These preliminary measures ensure that when capacitors are initially uncharged, current is limited to safe levels, preventing IGBT overheating while still enabling fast charging once the capacitor voltage reaches safe thresholds.
Solution Approach 2:
The patent introduces intermediary protective components (pre-charge resistors, current sensors, and control circuits) between the power source and the IGBT. These intermediaries monitor and regulate current flow, acting as a buffer that protects the IGBT from direct exposure to potentially damaging inrush currents while maintaining efficient charging operation.
4Reliability
If pre-charge resistors are used to limit current during capacitor charging, then IGBT overheating is prevented, but for large capacitor banks the resistors become very large and expensive
Solution Approach 1:
The patent implements dynamic resistance control where the pre-charge resistance is not fixed but varies during the charging process. The control system dynamically adjusts the resistance value based on real-time monitoring of capacitor voltage and current, using high resistance initially to limit inrush current, then progressively reducing resistance as charging progresses. This dynamic approach allows effective IGBT protection with smaller, more cost-effective resistor components compared to static high-power resistor designs.
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 system reduces harmonics, improves power factor, lowers acoustic noise, and prevents IGBT failure by controlling current flow, making it suitable for charging ultra-capacitors efficiently.
Implementation Method 1
a power converter configured to receive power from a power source... controlling the at least one IGBT to charge an array of ultra-capacitors
Data Source
AI summary
Provided is a system for an insulated-gate bipolar transistor (IGBT) rectifier for charging ultra-capacitors. The system may include a power converter, which may receive power from a power source. A direct current (DC) bus may be connected to the power converter and may receive power from the power converter. At least one IGBT may be connected to the DC bus and may receive power from the DC bus. An array of ultra-capacitors may be connected to the at least one IGBT. At least one controller may control the at least one IGBT to charge the array of ultra-capacitors. A method and computer program product are also disclosed.