Zigzag Power Switching Elements in Electric Power Steering Inverter
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Solution Overview
Problem
The existing electric power steering devices require size reduction and efficient heat dissipation, particularly in the radial direction, while maintaining a redundant system for the electronic control unit, which is challenging due to the large heat values of power switching elements.
Innovation Solution
The power conversion circuit unit is configured with power switching elements arranged in a zigzag formation along the control output terminal-side line, offset from the rotation shaft-side line, and packaged with synthetic resin, reducing the size and enhancing heat dissipation by increasing the metal wiring area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If power switching elements are arranged in a conventional linear formation, then the structure is simple, but the wire length is long and heat dissipation is insufficient
Solution Approach 1:
The patent transitions from a conventional linear arrangement of power switching elements to a three-dimensional stacked configuration. Multiple layers of power switching elements are vertically arranged with corresponding control output terminals positioned at different heights, enabling spatial optimization that reduces wire length while improving heat dissipation through increased surface area exposure.
2Volume of moving object
If the power conversion circuit unit size is reduced, then the radial space is saved, but heat dissipation area is reduced
Solution Approach 1:
The patent employs vertical stacking of power switching elements across multiple layers, transforming the heat dissipation approach from a two-dimensional surface problem to a three-dimensional spatial solution. This allows compact radial dimensions while maintaining adequate heat dissipation through vertical surface area and improved thermal pathways to heat sinks.
Solution Approach 2:
The power conversion circuit unit is segmented into multiple functional layers, with power switching elements distributed across different vertical levels. This segmentation allows optimized positioning of heat-generating components away from each other, reducing thermal interference while maintaining compact overall dimensions.
3Volume of moving object
If wire length between power switching elements and control output terminals is reduced, then the circuit unit size is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes vertical layering to position control output terminals at different heights corresponding to their associated power switching elements. This three-dimensional terminal arrangement naturally shortens connection paths while maintaining manufacturability through standardized multi-layer PCB or wiring board technologies.
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 configuration shortens wire lengths, reduces the size of the power conversion circuit unit, and improves heat releasing performance, achieving efficient size reduction and heat management.
Implementation Method 1
packaged with synthetic resin... improves heat releasing performance
Data Source
AI summary
Power conversion circuit unit defined by rotation shaft-side line facing toward rotation shaft of electric motor, control output terminal-side line facing toward coil input terminals of electric motor and side lines connecting both end portions of rotation shaft-side line and control output terminal-side line is packaged with synthetic resin. Three-phase control output terminals connected to the coil input terminals are formed at control output terminal-side line. Power switching elements forming upper and lower arms for each phase are arranged in a zigzag formation along control output terminal-side line with power switching elements being offset from a substantially middle between rotation shaft-side line and control output terminal-side line toward control output terminal-side line. With this, size of power conversion circuit unit can be reduced, and heat of power conversion circuit unit can be efficiently released to the outside.