Leakage Current Compensation Device for Vehicle Chargers

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Solution Overview

Problem

Existing solutions for compensating leakage currents in vehicle chargers are inefficient, particularly due to the complexity and cost of digital signal processing at low and high frequencies, and the need for effective frequency range evaluation.

Innovation Solution

A compensation device using a differential current measurement device, signal generation devices with analog filters, and an amplifier to generate and feed compensation currents, combining analog and digital signal processing for efficient frequency evaluation and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If digital signal processing is used for compensation current generation, then flexibility and control capability are improved, but device complexity and cost increase significantly at low and high frequencies

Engineering Contradiction:

Improvecontrol capabilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the signal processing task into two distinct parts: an analog signal processing unit for initial compensation current specification and a digital control unit for monitoring and optimization. This segmentation allows each unit to operate in its optimal frequency range and complexity level, reducing overall system complexity while maintaining control capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an analog intermediate stage (analog filter and analog signal processing) that acts as a mediator between the differential current measurement and the final compensation current generation. This analog intermediary processes signals in the time domain before digital processing, reducing the computational burden on digital circuits and lowering overall system complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If analog signal processing is used for compensation current generation, then device complexity and cost are reduced, but flexibility and adaptability are limited

Engineering Contradiction:

Improvecircuit complexityVSAvoidcontrol flexibility

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent merges analog and digital signal processing approaches into a hybrid architecture. The analog section handles real-time compensation current specification with low complexity, while the digital control unit provides monitoring, diagnostic functions, and adaptive optimization. This combination achieves both low device complexity and high adaptability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control unit is designed with multi-functionality, serving both as a monitor of the compensation device operation and as an optimizer that can adjust compensation parameters. This universal control architecture enhances adaptability without requiring separate dedicated circuits for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If frequency filters are applied in signal processing, then relevant frequency ranges are evaluated effectively, but device complexity increases

Engineering Contradiction:

Improvefrequency evaluation precisionVSAvoidfilter circuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex analog filter circuits with a digital filtering approach implemented in the control unit. Instead of using multiple analog filter stages to achieve precise frequency evaluation, the system uses digital signal processing algorithms that provide the same frequency selectivity with simpler hardware requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11366176B2Compensation device for leakage currents

Publication Date: 2022.06.21 DR ING H C F PORSCHE AG

AI summary

A compensation device for compensating leakage currents has a differential current measurement device, a first signal generation device, an amplifier and a feeder device. The first signal generation device is designed to generate a first compensation current specification signal (I_COMP_S1) suitable for the compensation from the first signal (I_DIFF) from the differential current measurement device by way of analog signal processing and to feed this first compensation current specification signal (I_COMP_S1) to the amplifier in analog or digitized form. The amplifier is designed to generate a compensation current (I_COMP) on the basis of the first compensation current specification signal (I_COMP_S1), and the feeder device is designed to allow the compensation current to be fed in at at least one of the active conductors.