Power Conversion Device Eddy Current Inductance Reduction
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Solution Overview
Problem
Existing power conversion devices have limited effectiveness in reducing parasitic inductance associated with semiconductor recovery currents, which affects the efficiency of power conversion.
Innovation Solution
A power conversion device design that includes a circuit body with a first and second switching element, conductor portions, a metal member, and a relay conductor plate, where an eddy current is induced in the metal member and relay conductor plate by the recovery current, effectively canceling the magnetic flux and reducing inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a metal member is arranged only on the outer face of one insulating board, then the device structure is simple, but the inductance reduction effect with respect to recovery current is small
Solution Approach 1:
The single metal member is divided into two separate metal members: one arranged on the outer face of the first insulating board and another on the outer face of the second insulating board. This segmentation allows each metal member to independently generate eddy currents that counteract the magnetic flux from recovery current, thereby enhancing the overall inductance reduction effect while maintaining structural simplicity
Solution Approach 2:
The solution transitions from a single-plane metal member configuration to a dual-plane configuration by placing metal members on both the first and second insulating boards. This dimensional expansion creates two opposing magnetic flux cancellation zones that work synergistically to reduce parasitic inductance more effectively than a single metal member could achieve
2Volume of moving object
If the circuit body size is reduced for compactness, then the device becomes more compact, but the inductance reduction effect may be compromised
Solution Approach 1:
Metal members are strategically positioned on the outer faces of the insulating boards where they can most effectively counteract the magnetic flux generated by recovery current. This localized placement ensures optimal inductance reduction at critical areas without requiring overall circuit body expansion, maintaining compact dimensions while achieving reliable inductance control
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 significantly enhances the reduction of inductance with respect to recovery currents, improving the efficiency of the power conversion process and allowing for a more compact and cost-effective power conversion device.
Implementation Method 1
an eddy current is induced at the metal member and the relay conductor plate by a recovery current flowing through the conductor portions
Implementation Method 2
The direction of the magnetic flux generated around this induced current is opposite to the direction of the magnetic flux generated by the recovery current flowing through each conductor plate of the upper and lower arm circuits. Thus, the magnetic fluxes cancel each other
Data Source
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AI summary
The effect of decreasing the inductance, which cancels the recovery current generated upon the switching operation of the switching element, is enhanced. Provided are a circuit body which has first and second switching elements constituting upper and lower arm circuits and a conductor portions, a metal member, and a relay conductor portion which is arranged to face the metal member with the circuit body interposed therebetween and electrically connected to a terminal connected to any one of conductor portions. An eddy current is induced at the metal member and the relay conductor portion by the recovery current flowing through the conductor portions according to the switching operation of the first and second switching elements.