Power Conversion Unit Asymmetric Control Wiring for Current Balance
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Solution Overview
Problem
Current power conversion systems face current imbalances due to parasitic resistance and inductance imbalances in both power and control signal wirings of power semiconductor elements connected in parallel, leading to reduced reliability and lifespan.
Innovation Solution
The solution involves a power conversion unit with parallel-connected power semiconductor modules and a control signal wiring circuit board, where the power semiconductor modules are arranged in a predetermined direction, and the control signal wiring distances are equalized to balance the control signals, thereby reducing current imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power semiconductor elements are connected in parallel to increase inverter capacity, then the power converter capacity increases, but current imbalance occurs due to parasitic resistance and inductance differences in power wirings
Solution Approach 1:
The patent applies asymmetry by intentionally designing unequal wiring lengths - specifically making the wiring length from the control signal generation unit to the first power semiconductor element longer than to the second element. This asymmetric design compensates for inherent differences in parasitic resistance and inductance of power wirings, balancing the overall impedance seen by each parallel-connected power semiconductor element and achieving current balance.
2Productivity
If power semiconductor elements are connected in parallel, then output current capacity increases, but current concentrates on elements with smaller parasitic resistance reducing their lifespan
Solution Approach 1:
The patent uses asymmetric wiring length design where the control signal wiring to the first power semiconductor element is intentionally made longer than to the second element. This creates compensating impedance differences that balance the current distribution across parallel-connected elements, preventing current concentration and extending element operational life.
3Ease of manufacture
If control signal wirings have unequal lengths, then installation flexibility improves, but control signal imbalance occurs affecting current distribution
Solution Approach 1:
The patent deliberately employs asymmetric control signal wiring lengths as a design feature rather than avoiding it. By making the wiring to the first power semiconductor element longer than to the second, the patent compensates for parasitic differences in power wirings, transforming what is typically a source of imbalance into a mechanism for achieving current balance.
Data Source
AI summary
An imbalance of control signals between two power semiconductor elements is reduced. A first power semiconductor module and a second power semiconductor module are arranged in a predetermined direction along a surface of a control signal wiring circuit board, each of longitudinal directions of the first power semiconductor module and the second power semiconductor module along the surface of the control signal wiring circuit board is a predetermined direction, and, in a first control signal wiring, a distance between an external control signal terminal and a second control signal terminal is equal to a distance between the external control signal terminal and a first control signal terminal.