Power Conversion Circuit Layout for Compact Electric Power Steering
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Solution Overview
Problem
The challenge is to densely mount redundant power conversion circuits on a mounting substrate for an electric power steering device without increasing the radial size of the ECU housing, as conventional methods either lengthen the axial dimension or enlarge the outside dimensions.
Innovation Solution
The solution involves arranging two positive-electrode-side power lines and two negative-electrode-side power lines adjacent to each other on the mounting substrate, with power conversion circuits positioned on both sides and output terminals located outward of the power conversion circuits, allowing for a shorter wiring length and smaller mounting area, thus preventing radial size increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two power conversion circuits are mounted on separate mounting substrates, then redundancy is achieved, but the axial length of the ECU housing becomes long
Solution Approach 1:
Two separate mounting substrates are merged into a single mounting substrate, allowing both power conversion circuits to be mounted on the same substrate. This combines spatial resources and eliminates the axial space required for stacking separate substrates, thereby reducing the axial length of the ECU housing while maintaining redundancy through dual circuit implementation on the same substrate.
Solution Approach 2:
The arrangement transitions from a vertical stacking configuration (separate substrates stacked axially) to a planar distribution configuration (circuits arranged radially on the same substrate). By changing from axial dimension utilization to radial dimension utilization, the patent achieves redundancy without increasing axial length, effectively resolving the contradiction between reliability and axial dimension.
2Length of moving object
If two power conversion circuits are mounted on the same mounting substrate, then axial length is reduced, but the radial length of the ECU housing becomes long
Solution Approach 1:
The power lines are arranged in a flexible, adaptive configuration rather than rigid fixed positions. The positive-electrode-side and negative-electrode-side power lines are positioned to optimize space utilization, allowing the circuits to be compactly arranged on the mounting substrate without excessive radial extension, thus reducing radial length while maintaining electrical functionality.
Solution Approach 2:
The patent changes the spatial arrangement parameters of the power lines and circuits on the mounting substrate. By optimizing the positioning of positive and negative power lines and arranging circuits between them, the design achieves compact radial dimensions. The output terminals are positioned outward of the circuits, optimizing the radial layout to minimize the overall radial footprint of the ECU housing.
3Ease of manufacture
If power conversion circuits are arranged with long wiring, then mounting is simpler, but the mounting area increases and radial size increases
Solution Approach 1:
The power line arrangement is dynamically optimized to balance wiring complexity and space utilization. Rather than using simple but lengthy wiring routes, the patent employs a compact radial arrangement where positive and negative power lines are positioned adjacently and extend outward in an organized manner. This dynamic optimization reduces the mounting area and radial size while maintaining manufacturing feasibility through systematic wire routing.
Data Source
AI summary
Disclosed is an electric driving device in which: two positive-electrode-side power lines (32, 33) are arranged from an outer peripheral side to an inner side of a mounting substrate (19); power conversion circuits (36, 37; 44, 45; 46, 47) are arranged on both sides of the mounting substrate, with respect to the positive-electrode-side power lines, to perform drive control of an electric motor; and output terminals (52, 53) are arranged on the mounting substrate at a location outward of the power conversion circuit so as to establish a connection to the electric motor. As the power conversion circuits are disposed from the center to the periphery of the mounting substrate, it is possible to decrease the wiring length and circuit mounting area of the mounting substrate (19) and suppress a radial size increase of the mounting substrate on which the redundant power conversion circuits are mounted.