Chopping Converter With Coupled Windings For Short Circuit Protection
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Solution Overview
Problem
Conventional chopping current sources with magnetically coupled windings face challenges in size, cost, and electromagnetic compatibility, particularly in high-frequency applications and aeronautical environments, due to high dependency on load inductance and difficulty in managing short circuits and electromagnetic compatibility.
Innovation Solution
A chopping converter with two windings coupled on a single magnetic core, utilizing diodes and switches to manage voltage and current, allowing for configuration as either a voltage source or current source, and incorporating a smoothing capacitor to reduce size and cost while enhancing compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If chopping current sources use the inductance of the load as energy storage element, then the control is simple and few inductive elements are required, but the dependency on load inductance value is high and short circuit current cannot be limited
Solution Approach 1:
The patent introduces an intermediary inductance element (Lc) between the converter output and the load. This intermediary component serves as a buffer that limits short circuit current while allowing the control system to maintain simplicity. The inductance Lc acts as a mediator that protects the system during faults without complicating the control architecture.
2Volume of stationary object
If chopping frequency is increased to limit passive component size, then converter size is reduced, but electromagnetic compatibility with aeronautic standards becomes difficult to achieve
Solution Approach 1:
The patent extracts the electromagnetic interference problem from the converter by adding output filtering components (capacitor Cc and inductance Lc) that form an LC filter. This separates the high-frequency switching operations from the output, allowing high chopping frequencies to be used while meeting electromagnetic compatibility standards through dedicated filtering.
3Object-affected harmful factors
If output filter is added to meet electromagnetic compatibility standards, then emissions are reduced, but the filter size becomes non-negligible and stability becomes more critical
Solution Approach 1:
The patent optimizes the parameters of the filtering components (capacitor Cc and inductance Lc) to achieve effective electromagnetic filtering with minimal size. By carefully selecting the values of these components based on the chopping frequency and load characteristics, the filter provides adequate emission reduction while keeping the overall converter size compact.
4Reliability
If inductance is added at output to limit short circuit current, then current limitation is achieved, but additional protection devices and demagnetising circuits are required
Solution Approach 1:
The patent combines multiple functions into the output inductance Lc and capacitor Cc: current limitation during short circuits, electromagnetic filtering, and energy storage for continuous output. This merging of functions reduces the need for separate protection devices and demagnetising circuits, simplifying the overall protection system while maintaining reliability.
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 the size and cost of the converter, improves electromagnetic compatibility, and enables higher chopping frequencies, addressing the limitations of conventional designs by effectively managing short circuits and meeting aeronautical standards.
Implementation Method 1
Two windings wound in opposition around a magnetic core
Implementation Method 2
a smoothing capacitor C1 is connected between the output S1P and the earth
Data Source
AI summary
In order to reduce the cost of a chopping converter supplying a continuous voltage at the terminals of a load (Z), a circuit with two windings (Lp, Ls) and a single magnetic core is proposed, according to the present invention, which enables the cost and the size of the circuit to be reduced. It is then necessary to add two diodes (D3, D4) to the circuit, but these elements are inexpensive and of small size.