IGBT Rectifier Control for Ultra-Capacitor Charging From Zero Voltage
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Solution Overview
Problem
Existing rectifiers for charging capacitors, such as diode bridge rectifiers and Thyristor rectifiers, suffer from high harmonic distortion, acoustic noise, and low power factor, and Insulated-Gate Bipolar Transistors (IGBTs) are not suitable due to potential overheating when charging capacitors from a zero charge state.
Innovation Solution
A system and method using an IGBT rectifier with a power converter, DC bus, and controller to charge ultra-capacitors, incorporating a diode bridge rectifier and pre-charge circuit to manage current and voltage, reducing harmonic distortion and noise, and preventing overheating through controlled current supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IGBT is used to charge capacitor from zero charge state, then charging speed is improved, but IGBT overheating and failure occurs
Solution Approach 1:
The system performs preliminary action by detecting when capacitor voltage is below a threshold (indicating near-zero charge state) and proactively reducing the IGBT duty cycle before excessive current can flow. This preventive measure avoids the overheating and failure that would occur if charging started at full power, thus resolving the contradiction between fast charging and reliability.
2Device complexity
If conventional rectifiers are used, then simplicity is maintained, but harmonic distortion and acoustic noise increase
Solution Approach 1:
The patent replaces conventional mechanical/electronic rectifiers (diode bridge, Thyristor rectifiers) with an IGBT-based controlled rectifier system. This substitution eliminates the high harmonic distortion and acoustic noise inherent in traditional rectifiers while maintaining the essential rectification function, thus resolving the contradiction between device simplicity and harmful factor reduction.
3Reliability
If pre-charge resistors are used to limit current, then IGBT overheating is prevented, but energy waste and cost increase
Solution Approach 1:
The system employs dynamic control of the IGBT duty cycle based on real-time capacitor voltage detection. Instead of using a fixed pre-charge resistor that continuously dissipates energy, the controller dynamically adjusts the IGBT switching ratio - using lower duty cycles when capacitor voltage is low (preventing overheating) and higher duty cycles when voltage is sufficient (reducing energy waste). This dynamic adaptation resolves the contradiction between reliability and energy efficiency.
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 reduces harmonic distortion, acoustic noise, and improves power factor, while preventing overheating during capacitor charging, making it suitable for large ultra-capacitor banks.
Implementation Method 1
the power converter may be configured to convert AC power from the AC power supply to DC power to be supplied to the DC bus
Implementation Method 2
at least one IGBT connected to the DC bus and configured to receive power from the DC bus; controlling the at least one IGBT to charge the 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.