Fuel Cell Voltage Synchronization via Offset Compensation

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Solution Overview

Problem

Fuel cell vehicles face challenges in achieving precise control and performance due to voltage differences among high voltage components, leading to derating issues during regenerative braking and cold starts, which result in reduced energy recovery, increased vibration, and prolonged cold start times.

Innovation Solution

A method for synchronizing voltages of high voltage components in real-time, involving a default voltage synchronization step and a real-time voltage synchronization step, where auxiliary controllers correct voltages based on stored offset values and a target offset value calculated by the main controller, ensuring all components operate within a unified voltage range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If voltage control is performed based on minimum permissible voltage during cold start to increase heat generation, then cold start time is reduced, but control precision deteriorates due to voltage differences among components

Engineering Contradiction:

Improvecold start timeVSAvoidvoltage control precision

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by performing voltage synchronization before cold start operation. The system pre-calculates and stores offset values for each voltage measuring device based on their differences, so that when cold start occurs, the correct compensated voltage values are already available, enabling both rapid response and precise control.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of voltage measurement by introducing offset compensation. Each voltage measuring device applies its specific offset value to compensate for measurement differences, transforming the raw voltage readings into synchronized, comparable values that enable precise control during cold start and other operations.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If regenerative braking is performed when voltage difference exists among components, then energy recovery is attempted, but control precision deteriorates causing derating and reduced energy recovery

Engineering Contradiction:

Improveenergy recoveryVSAvoidvoltage control precision

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent changes the voltage measurement parameters by applying offset compensation to each measuring device. This ensures that all controllers work with synchronized voltage values, preventing derating caused by measurement discrepancies and maximizing regenerative braking energy recovery.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If voltage synchronization is performed using traditional methods waiting for vehicle start-up completion, then system stability is maintained, but response time increases and control precision is reduced

Engineering Contradiction:

Improvevoltage control precisionVSAvoidsynchronization time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs voltage synchronization in advance during system initialization, before vehicle start-up completion. It pre-measures voltage differences among all measuring devices, calculates offset values, and stores them for immediate use, eliminating the need to wait for start-up completion before synchronization can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent prepares offset compensation values in advance to cushion against voltage measurement differences that would otherwise cause control imprecision. By having these compensation values ready beforehand, the system can immediately achieve precise voltage control without waiting for traditional synchronization methods.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If derating is performed to protect high voltage components when voltage reaches maximum or minimum, then component reliability is improved, but control precision deteriorates due to voltage differences

Engineering Contradiction:

Improvecomponent protectionVSAvoidvoltage control precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the voltage measurement parameters by applying offset compensation to each measuring device. This ensures that all controllers have synchronized voltage values, allowing accurate determination of when derating should occur and preventing premature or delayed protection actions, thus maintaining both reliability and control precision.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10270110B2Method for synchronizing voltage of fuel cell vehicle

Publication Date: 2019.04.23 HYUNDAI MOTOR CO LTD

AI summary

A method for synchronizing voltages of a fuel cell vehicle may synchronize the voltages of high voltage components in real time regardless of the completion of vehicle start-up in order to improve performance and control precision within a full range of operable voltages. The method includes a default voltage synchronization step in which, when the fuel cell vehicle starts, the voltages of the high voltage components are corrected based on an offset value, stored in advance in multiple auxiliary controllers for controlling the high voltage components, and the corrected voltages are further corrected according to a default voltage synchronization command of a main controller; and a real-time voltage synchronization step in which, after the default voltage synchronization step, the main controller transmits a target offset value to the auxiliary controllers, and the auxiliary controllers correct the voltages based on the target offset value.