Auxiliary Coil Flyback Transformer for Choke Current Management
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Solution Overview
Problem
Existing power conversion apparatuses face inefficiencies and potential circuit damage due to inrush currents and avalanche currents, leading to performance deterioration and component breakdown, particularly in the absence of current limiting resistors.
Innovation Solution
A power conversion apparatus with a choke coil, auxiliary coil, and rectifier element, where the auxiliary coil functions as a flyback transformer to manage currents and prevent excessive flow, thereby reducing stress on switching elements and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a two-way converter includes a choke coil without current limiting resistors to reduce system cost and size, then system cost and size are reduced, but inrush current and avalanche current cause performance deterioration and component breaking
Solution Approach 1:
The patent introduces an auxiliary coil magnetically coupled to the choke coil that acts as an intermediary to manage avalanche current. When the main switching elements are turned off, the auxiliary coil generates a counter-electromotive force that opposes the avalanche current, preventing damage to the switching elements while maintaining system compactness without current limiting resistors
Solution Approach 2:
The patent converts the harmful avalanche current into a beneficial effect by using the auxiliary coil to generate a counter-electromotive force. The avalanche current that would normally damage components is transformed into a controlled magnetic flux in the auxiliary coil, which then produces a protective counter-voltage to limit the current and protect the switching elements
2Power
If switching elements are turned off to decrease current flowing through the choke coil, then current is decreased, but counter-electromotive force from avalanche current causes switching element deterioration
Solution Approach 1:
The auxiliary coil is pre-configured with specific winding direction and magnetic coupling to the choke coil, creating a preliminary protective mechanism. When the main switching elements are turned off, the auxiliary coil automatically generates a counter-electromotive force that opposes the avalanche current before it can damage the switching elements, providing preemptive protection
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 effectively restricts performance deterioration and breaking of circuit components by managing currents and efficiently supplying power, while maintaining high conversion efficiency.
Implementation Method 1
The auxiliary coil L14 is magnetically coupled to the choke coil L13. The auxiliary coil is wound in a direction so that an excitation current in the output side circuit flows from a negative electrode of the output side circuit to a positive electrode of the output side circuit when an excitation current of the direct current power source flows from a positive electrode of the direct current power source to a negative electrode of the direct current power source through the choke coil.
Data Source
AI summary
A power conversion apparatus includes a power conversion circuit, a choke coil, an auxiliary coil, and a rectifier element. The choke coil is disposed between the power conversion circuit and an input side direct current power source. The auxiliary coil is magnetically coupled to the choke coil and is connected in parallel with an output side circuit. The auxiliary coil is wound in a direction so that an excitation current flows from a negative electrode to a positive electrode of the output side circuit when an excitation current flows from a positive electrode to a negative electrode of the direct current power source through the choke coil. The rectifier element is series connection with the auxiliary coil, and cuts off power supply from the direct current power source to the output side circuit through the auxiliary coil and power supply from the output side circuit to the input side.