Common Mode Reactor for Insulated Power Source Leakage Current
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Solution Overview
Problem
High-frequency operation in power conversion devices generates a high-frequency displacement voltage that causes leakage currents through parasitic capacitors in insulated transformers, leading to erroneous operations of switching elements and requiring suppression of these currents.
Innovation Solution
Incorporating a common mode reactor between the high-side insulated power source and the high-side driving circuit to bear the displacement voltage and suppress common mode currents, thereby reducing leakage currents and preventing erroneous operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-frequency switching operation is performed to improve power conversion efficiency, then productivity is improved, but high-frequency displacement voltage generates leakage currents through parasitic capacitors causing erroneous operations and reducing reliability
Solution Approach 1:
A common mode reactor is introduced as an intermediary component between the insulated power source and the high-side switching element. This reactor bears the high-frequency displacement voltage generated during switching operations, preventing it from causing leakage currents through the parasitic capacitor of the high-side switching element, thus eliminating erroneous operations while maintaining high-frequency switching efficiency
2Reliability
If insulated power source is used to electrically insulate high side and low side, then reliability is improved by preventing short-circuiting, but device complexity increases due to additional insulation components
Solution Approach 1:
The common mode reactor is designed to serve multiple functions: it provides electrical insulation between high and low sides, bears high-frequency displacement voltage, and suppresses common mode currents. By consolidating these functions into a single component, the overall device complexity is reduced compared to using separate components for each function
3Reliability
If common mode reactor is added to suppress common mode currents, then reliability is improved by preventing erroneous operations, but device complexity increases due to additional components
Solution Approach 1:
The common mode reactor is merged with the existing insulated power source configuration, combining the insulation function and the common mode suppression function into an integrated system. This merging approach reduces the need for separate additional components and simplifies the overall circuit design 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 common mode reactor effectively inhibits the passage of common mode currents, reducing leakage currents through parasitic capacitors and preventing erroneous operations of high-side switching elements, thus enhancing the reliability of power conversion devices.
Implementation Method 1
a common mode reactor between a high-side insulated power source and a high-side driving circuit on the high side to bear a displacement voltage
Data Source
Figure 1(a)~1(d)
Figure 2(a)~2(c)
Figure 3
AI summary
To suppress a leakage current flowing through a parasitic capacitor of an insulated transformer of a high-side insulated power source resulting from a high-frequency signal generated by a high-frequency operation of a switching element. The present invention suppresses a common mode current using a common mode reactor by focusing on the fact that a leakage current flowing through a parasitic capacitor of an insulated transformer of a high-side insulated power source resulting from a high-frequency signal generated due to an on/off operation of a high-side switching element is the common mode current. The common mode reactor reduces the common mode current and bears the high-frequency signal to prevent the high-frequency signal from being applied to the insulated transformer of the high-side insulated power source, suppress the leakage current flowing through the parasitic capacitor of the insulated transformer, and reduce an erroneous operation of the high-side switching element generated due to the leakage current flowing through the parasitic capacitor of the insulated transformer.