Power Converter Inrush Suppression via Leakage Inductance Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power conversion apparatuses face challenges in suppressing inrush current, which leads to electromagnetic interference and increased power consumption, especially during the initial operation when the capacitor is not charged.
Innovation Solution
A power conversion apparatus and control method that utilize a transformer-based auxiliary circuit to provide leakage inductance energy, allowing a switching circuit to control conduction paths between an inrush suppression component and an output capacitor, switching from a high-impedance path to a low-impedance path after initial operation to reduce inrush current and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thermal resistor with NTC is connected between the full-bridge rectifier and the capacitor to suppress inrush current, then inrush current is suppressed, but power consumption becomes too high
Solution Approach 1:
The patent applies a switching circuit that dynamically changes the conduction path based on the charging state of the output capacitor. During initial power-on, the switching circuit directs current through the inrush suppression component. After the capacitor is charged, the switching circuit switches to a low-impedance path, dynamically adapting the circuit configuration to eliminate continuous power loss while maintaining inrush suppression capability.
Solution Approach 2:
The patent extracts the inrush suppression function from the main power conduction path by using a separate auxiliary circuit with a transformer. The transformer-based auxiliary circuit provides a dedicated path for inrush current suppression that can be independently controlled, allowing the main power path to operate with low impedance during normal operation without continuous power loss.
2Stability of the object's composition
If a capacitor with large capacitance is used to filter DC signal and provide stable output voltage, then output stability is improved, but inrush current increases at initial operation
Solution Approach 1:
The patent introduces a transformer-based auxiliary circuit as an intermediary between the AC-to-DC conversion circuit and the output capacitor. This auxiliary circuit with leakage inductance acts as a buffer that limits inrush current while still allowing the large capacitance capacitor to perform its voltage stabilization function effectively.
Solution Approach 2:
The patent segments the power conduction path into multiple paths: a first conduction path through the inrush suppression component for initial power-on, and a second conduction path through the switching circuit for normal operation. This segmentation allows the large capacitance capacitor to be charged safely while maintaining voltage stability during operation.
3Object-affected harmful factors
If a thermal resistor with higher equivalent high impedance value is used to dissipate inrush current energy, then inrush current suppression is improved, but power consumption increases and performance is reduced
Solution Approach 1:
The patent uses a switching circuit to dynamically change the impedance characteristics of the conduction path. During initial power-on, the circuit presents high impedance through the inrush suppression component to limit inrush current. After the output capacitor is charged, the switching circuit transitions to a low-impedance path, optimizing power conversion performance and eliminating continuous power loss.
Solution Approach 2:
The patent implements periodic control of the switching circuit based on the charging state of the output capacitor. The switching circuit is activated during initial power-on to provide inrush suppression, then deactivated during normal operation to minimize power loss, creating a periodic on-off pattern that balances inrush suppression with 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
Effectively suppresses inrush current during booting and reduces power consumption by switching to a low-impedance conduction path after the output DC power stabilizes, without requiring additional control signals, thus simplifying circuit design and improving performance.
Implementation Method 1
The transformer-based auxiliary circuit provides a leakage inductance energy
Implementation Method 2
a thermal resistor having a Negative Temperature Coefficient (NTC) is usually connected between the full-bridge rectifier and the capacitor having the large capacitance
Data Source
AI summary
A power conversion apparatus and control method thereof are provided. The power conversion apparatus includes an output capacitor, an AC-to-DC conversion circuit, a transformer-based auxiliary circuit, an inrush suppression component and a switching circuit. The AC-to-DC conversion circuit is configured to convert an AC power into a DC power. The auxiliary circuit provides a leakage inductance energy. The inrush suppression component provides a first conduction path, and the switching circuit provides a second conduction path. When the switching circuit cuts off the second conduction path in response to the leakage inductance energy, the AC-to-DC conversion circuit conducts the DC power to the output capacitor via the first conduction path. When the switching circuit turns on the second conduction path in response to the leakage inductance energy, the AC-to-DC conversion circuit conducts the DC power to the output capacitor via the second conduction path.