Coil-Free Power Ripple Filter for Electric Vehicle Electronics

Solution Overview

Problem

Existing electric vehicles face issues with large, heavy, and costly induction coils used to filter frequency ripples in the motor power electronics system, which are disruptive and inefficient.

Innovation Solution

A coil-free power ripple filter is implemented using two line sections with a conductor core and insulator, connected to the vehicle ground with low-ohmic resistance, providing effective shielding and damping in the 10 Hz to 150 kHz range without the need for a damping coil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If induction coils are used to filter ripples in the motor power electronics system, then the electrical ripples are smoothed, but the filter becomes large, heavy and costly

Engineering Contradiction:

Improveripple filtering effectivenessVSAvoidfilter weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent extracts the essential filtering function from traditional induction coils by removing the coil structure entirely. The solution uses two straight conductor cores with insulator coatings instead of coiled structures, maintaining ripple filtering effectiveness while dramatically reducing weight and volume. This extraction of the core function (electrical conduction and shielding) from the conventional coil form factor resolves the contradiction between filtering effectiveness and weight.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the geometric parameters of the filter components by using straight conductor cores instead of coiled structures. The insulator coating thickness is specified as 0.5-2.0 mm to provide adequate shielding. By changing from a three-dimensional coiled structure to linear conductors with controlled insulation thickness, the filter achieves comparable electrical performance with significantly reduced mass and volume.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If induction coils are used to filter ripples, then the electrical ripples are smoothed, but the device complexity and cost increase

Engineering Contradiction:

Improveripple filtering effectivenessVSAvoidfilter structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential filtering function from traditional induction coils by removing the coil structure entirely. The solution uses two straight conductor cores with insulator coatings instead of coiled structures, maintaining ripple filtering effectiveness while dramatically reducing weight and volume. This extraction of the core function (electrical conduction and shielding) from the conventional coil form factor resolves the contradiction between filtering effectiveness and weight.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The filter is segmented into two independent conductor cores, each with its own insulator coating and ground connection. This segmentation allows for simplified manufacturing and assembly compared to a single complex coil structure, while maintaining the necessary filtering capability through the combined effect of both conductors.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If thick insulator coating is used for shielding, then the shielding damping is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improveshielding damping effectivenessVSAvoidinsulator application complexity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent changes the geometric parameters of the filter components by using straight conductor cores instead of coiled structures. The insulator coating thickness is specified as 0.5-2.0 mm to provide adequate shielding. By changing from a three-dimensional coiled structure to linear conductors with controlled insulation thickness, the filter achieves comparable electrical performance with significantly reduced mass and volume.

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

This solution results in a compact, lightweight, and cost-effective power ripple filter that effectively shields and dampens low-frequency ripples, eliminating the need for a damping coil and allowing for modular integration into the electric vehicle's electronics system.

Implementation Method 1

The motor power electronics system of an electric vehicle operates at high voltages of more than 100 V. Thus, a skin effect is produced at electrical conductor cores and conductor insulators. This skin effect causes what is known as shielding damping.

Methodology Applied

Scientific EffectSkin effect: Skin Effect

Data Source

PatentUS11148535B2Electric vehicle

Publication Date: 2021.10.19 DR ING H C F PORSCHE AG

AI summary

An electric vehicle (10) has a traction battery (16), an electric traction motor (12) and a motor power electronics system (14) that feeds electrical energy to the traction motor (12) and is electrically connected to the traction battery (16). A coil-free, two-wire power ripple filter (20) having two line sections (22, 22′) is arranged between the motor power electronics system (14) and the traction battery (16). Each two line section each is formed by a conductor core (28) and a conductor insulator (24). Each conductor insulator (24) has a thickness (D) of at least 1.0 mm and each is connected conductively to the vehicle ground (30) by way of an electrical ground connection (31, 32). The ohmic resistance of the ground connection (31, 32) between the conductor insulator (24) and the vehicle ground (30) is in each case at most 10 mOhms.