Multilayer PCB DC-Side Connection for Drive System Vibration Damping

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Solution Overview

Problem

Existing drive systems face challenges in achieving a cost-effective, stable, and compact design for high-power applications, particularly in efficiently connecting the DC-side terminal of a mains-powered rectifier to the inverter in electric motor systems, where mechanical vibrations and high voltages pose issues.

Innovation Solution

A multilayer printed circuit board is used to connect the DC-side terminal of the rectifier to the inverter, featuring layers with different potentials and insulating materials, acting as a low-inductance current-carrying means and capacitor to dampen vibrations and manage high voltages, while allowing for high current transmission and efficient heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If busbars are used to conduct electricity in high-power applications, then high current transmission is achieved, but the structure becomes less compact and more prone to mechanical vibrations

Engineering Contradiction:
Improvecurrent transmission capacityVSAvoidconnection structure compactness
Core Design Contradiction:
Quantity of substanceVSVolume of moving object

Solution Approach 1:

The patent replaces traditional mechanical busbar connections with a printed circuit board (PCB)-based electrical connection system. The PCB with copper traces and vias conducts high currents while providing a compact, integrated structure that eliminates the need for separate busbars and their associated mounting hardware, thus achieving both high current capacity and compactness

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses a composite structure combining the PCB substrate (fr4 material) with copper conductors and solder joints to create a connection system that can handle high-power applications. The composite nature of the PCB (fiberglass reinforcement with resin matrix) provides both mechanical stability and electrical conductivity, replacing traditional metal busbars

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If traditional connection means are used for DC-side terminals, then mechanical stability is achieved, but the structure is less compact and more complex to produce

Engineering Contradiction:
Improvemechanical stabilityVSAvoidconnection structure compactness
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The patent merges the electrical connection function with the mechanical support function into a single integrated PCB structure. The PCB simultaneously provides electrical pathways for current transmission and mechanical mounting for the rectifier and inverter terminals, eliminating the need for separate connection components and reducing overall structural complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The PCB serves multiple functions: it acts as an electrical conductor for high currents, provides mechanical support and mounting for components, offers insulation between different potential terminals, and enables compact integration of the rectifier and inverter. This multi-functionality replaces traditional specialized connection components

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If layers with different potentials are placed directly adjacent to each other, then low inductance is achieved, but high voltage breakdown risk increases

Engineering Contradiction:
ImproveinductanceVSAvoidvoltage breakdown resistance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses thin insulating films (dielectric layers) between adjacent copper traces on the PCB to provide electrical insulation while maintaining close spacing. The insulating film thickness is optimized to prevent voltage breakdown at high voltages (e.g., 1000V) while keeping the inductance low due to the close proximity of opposing current carriers

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the insulation parameter by using PCB material with specific dielectric strength properties (fr4 material) that can withstand high voltages. The trace spacing and insulating film thickness are carefully controlled to achieve the right balance between low inductance (requiring close spacing) and high voltage breakdown resistance (requiring sufficient insulation)

Inventive Principle:
Principle #35Parameter changes

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 solution provides a stable, compact, and cost-effective connection with low inductance and high capacitance, effectively reducing mechanical vibrations and enabling the transmission of high voltages, thus enhancing the reliability and efficiency of the drive system.

Implementation Method 1

Because the plate-shaped interconnects are only slightly spaced apart and acted upon by different potential and therefore form a capacitor. This has a dampening effect on electrically otherwise building up vibrations.

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

Insulating material is arranged between the layers aligned parallel to one another, wherein between adjacent layers, in particular directly adjacent layers, Voltages of up to 1000 volts occur. The insulating material has a corresponding insulation resistance.

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP3491729A1Drive system having a converter
Publication Date: 2019.06.05 SEW EURODRIVE GMBH & CO KG

AI summary

The invention relates to a drive system having a converter, comprising an inverter for feeding an electric motor and comprising a mains-fed rectifier, the direct-voltage-side connection of which provides an intermediate circuit voltage for supplying the inverter, wherein the direct-voltage-side connection of the rectifier is connected to the direct-voltage-side connection of the inverter by means of a multi-layer circuit board.