Stacked Semiconductor Chips in Voltage Source Converters
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Solution Overview
Problem
Voltage Source Converters used for high-power applications are bulky due to the large number of series-connected switching elements and energy storing capacitors, leading to increased space requirements for equipment such as valve halls in HVDC plants, and existing solutions do not effectively reduce size or enhance reliability of semiconductor chip connections.
Innovation Solution
The semiconductor chips in the switching elements are arranged in stacks and pressed together using a presspack technique with spring-loaded pressure to ensure reliable electric contact, allowing for a more compact design and reduced equipment size, with optional cooling mechanisms and insulating layers to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high number of switching elements are connected in series to handle high voltages and transmit high powers, then the converter can achieve high power transmission capability and sinusoidal voltage output, but the converter becomes voluminous and requires large valve halls
Solution Approach 1:
The patent implements a nested structure where switching elements are stacked vertically with semiconductor chips arranged in series within each stack. Multiple stacks are connected in parallel, with each stack containing multiple chips nested one above another. This three-dimensional nesting arrangement allows high voltage handling capability to be achieved within a compact volume, eliminating the need for large valve halls while maintaining the required power transmission capability.
2Reliability
If semiconductor chips are connected using conventional methods, then the converter can be assembled, but the connections occupy more space and reduce reliability
Solution Approach 1:
Semiconductor chips are arranged in vertical stacks with each chip nested above another, connected through common bonding pads. This nested arrangement eliminates the need for extensive lateral wiring and reduces the space required for connections while improving reliability through direct vertical bonding paths.
Solution Approach 2:
The patent merges multiple functions into the stack structure: electrical connection, mechanical support, and thermal management are all integrated into the same vertical stack assembly. The common bonding pads serve as both electrical interconnects and mechanical bonding points, reducing the number of separate connection components needed.
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
This approach results in a more compact and reliable Voltage Source Converter, reducing the size of valve halls and improving the quality of alternating voltage output while minimizing losses and harmonic currents, and allows for efficient cooling and reduced connections, making the equipment less costly.
Implementation Method 1
said converter comprises an arrangement configured to apply a pressure to opposite ends of each said stack for pressing said chips towards each other so as to obtain electric contact between semiconductor chips in said stack
Implementation Method 2
said converter comprises means configured to circulate a cooling medium in said channels for cooling said semiconductor chips adjacent to said metal plates
Data Source
Figure 1
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Figure 5~6
AI summary
A Voltage Source Converter having at least one phase leg connected to opposite poles of a direct voltage side of the converter and comprising a series connection of switching elements (7!) including at least one energy storing capacitor and configured to obtain two switching states, namely a first switching state and a second switching state, in which the voltage across said at least one energy storing capacitor and a zero voltage, respectively, is applied across the terminals of the switching element, has semiconductor chips of said switching elements arranged in stacks (S) comprising each at least two semiconductor chips. The converter comprises an arrangement (39) configured to apply a pressure to opposite ends of each stack.