Power Module Triangular Layout for Oscillation Suppression
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Solution Overview
Problem
Power modules experience oscillations due to PETT and IMPATT phenomena, which can lead to malfunction and breakage of semiconductor elements, and existing methods to suppress these oscillations are inadequate, especially when semiconductor elements with different impurity concentrations are used.
Innovation Solution
A power module design featuring two semiconductor elements with electrodes on both surfaces, connected by flat-plate-shaped electrically conductive metal patterns and capacitive elements arranged in a triangular configuration, where the metal patterns have a thickness equal to or greater than twice the skin depth for specific resonance frequencies, reducing vibrations caused by PETT and IMPATT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power semiconductor elements are connected and driven in parallel, then power conversion capability is improved, but oscillations occur due to LC resonance and parameter differences
Solution Approach 1:
A damping resistor is introduced as an intermediary component connected in series with each power semiconductor element. This damping resistor acts as a mediator that suppresses oscillations and equalizes current distribution among parallel-connected elements, preventing harmful resonances while maintaining the power conversion capability of the parallel configuration.
Solution Approach 2:
The invention changes the electrical parameters of the circuit by introducing resistive elements with specific resistance values in series with each power semiconductor element. This parameter modification alters the circuit's impedance characteristics, damping factor, and current distribution, thereby suppressing oscillations and improving stability without sacrificing power handling capability.
2Reliability
If damping resistors are connected in series with power semiconductor elements, then oscillations are suppressed and current is equalized, but voltage loss increases due to the resistance
Solution Approach 1:
The damping resistors are designed with resistance values that are sufficient to suppress oscillations and equalize current distribution, but not excessively large to cause significant voltage loss. The resistance values are optimized to provide just enough damping effect while minimizing energy loss, representing a balanced partial action rather than full or excessive resistance.
Solution Approach 2:
The resistance values of the damping resistors are carefully selected and optimized to achieve the desired balance between oscillation suppression and voltage loss. By adjusting this critical parameter, the invention minimizes energy loss while maintaining effective damping of oscillations and equalization of current among parallel elements.
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 design effectively disperses vibration currents across multiple paths, preventing concentration and thus suppressing oscillations and ensuring stable operation even when semiconductor elements have different characteristics.
Implementation Method 1
a capacitive element disposed, on the same plane, between the first electrically conductive metal pattern and the second electrically conductive metal pattern and forming a capacitance between the first electrically conductive metal pattern and the second electrically conductive metal pattern
Implementation Method 2
the first electrically conductive metal pattern and the second electrically conductive metal pattern each have a thickness that is equal to or larger than two times a depth of a skin through which current flows owing to skin effect generated by the first resonance frequency, the second resonance frequency, and the third resonance frequency of current paths
Data Source
AI summary
Two semiconductor elements and a capacitive element are located at vertices of a triangle. A first shortest path between the semiconductor elements, and a second shortest path and a third shortest path between the capacitive element and the two respective semiconductor elements, satisfy (first shortest path)≥(second shortest path) and ((first shortest path)2+(second shortest path)2)≥(third shortest path)2. A first electrically conductive metal pattern and a second electrically conductive metal pattern each have a thickness that is equal to or larger than two times a depth of a skin through which current flows owing to skin effect generated according to frequency characteristics of current paths having: a first resonance frequency obtained from capacitances and inductances between the semiconductor elements; a second resonance frequency between one of the semiconductor elements and the capacitive element; and a third resonance frequency between another one of the semiconductor elements and the capacitive element.