High-Voltage Discharge Circuit Control for Vehicle Intermediate Circuits

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Solution Overview

Problem

Conventional high-voltage vehicle electrical systems lack efficient methods and devices for discharging intermediate circuits, particularly those with capacitors, to safely manage voltage levels and minimize power loss.

Innovation Solution

A method and device that determine the voltage across a high-voltage intermediate circuit and control a discharge circuit based on predefined operating ranges, adjusting current flow to minimize power loss and ensure safe discharge, with options to increase or decrease current inversely proportional to voltage and limit currents to prevent overloading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a discharge circuit is continuously active to ensure safe voltage discharge, then safety is improved, but power loss increases

Engineering Contradiction:

ImprovesafetyVSAvoidpower loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The discharge circuit's current flow is dynamically adjusted based on real-time voltage measurements. The control unit monitors the intermediate circuit voltage and modulates the discharge circuit operation accordingly, transitioning from continuous discharge to conditional discharge based on voltage thresholds, thereby reducing unnecessary power consumption while maintaining safety

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the discharge circuit based on voltage levels. When voltage is within the operating range, the discharge circuit is deactivated or operated at minimal current. When voltage exceeds thresholds, the discharge circuit parameters are adjusted to increase current flow, optimizing both safety and energy efficiency

Inventive Principle:

Principle #35Parameter changes

2Speed

If the discharge circuit operates with high current to quickly reduce voltage, then discharge speed is improved, but power loss increases

Engineering Contradiction:

Improvedischarge speedVSAvoidpower loss

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The discharge circuit operates periodically rather than continuously, activating only when voltage exceeds predefined thresholds and deactivating when voltage returns to the operating range. This periodic operation reduces overall power loss while maintaining adequate discharge speed when needed

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The discharge circuit applies high current only partially - specifically when voltage exceeds the upper threshold - rather than maintaining high current continuously. This partial action provides sufficient discharge speed during critical moments while minimizing energy loss during normal operating conditions

Inventive Principle:

Principle #16Partial or excessive action

3Loss of energy

If voltage is continuously monitored and discharge circuit controlled to minimize power loss, then energy efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvepower lossVSAvoidcontrol complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The control unit implements feedback control by continuously monitoring intermediate circuit voltage and adjusting discharge circuit operation based on measured values. This closed-loop feedback mechanism optimizes power loss reduction while maintaining manageable complexity through automated voltage-based decision logic

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control unit serves multiple functions: it monitors voltage, determines whether voltage is within operating ranges, activates the discharge circuit when needed, and modulates current levels. This multi-functionality consolidates control complexity into a single device rather than requiring separate systems for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 efficiently manages high-voltage discharge in vehicle systems, minimizing power loss and ensuring safe operation by dynamically controlling the discharge current based on voltage levels, thereby extending the lifespan of components and enhancing safety.

Implementation Method 1

a switchable resistor which is used to dissipate the charge

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11577611B2Method and device for discharging a high-voltage intermediate circuit of a vehicle with a discharge unit

Publication Date: 2023.02.14 ROBERT BOSCH GMBH

AI summary

The invention relates to a method (400) for discharging a high-voltage intermediate circuit (110) with a discharge circuit (120), wherein the high-voltage intermediate circuit (110) comprises an intermediate circuit capacitor (130), having the steps of: ascertaining (410) the voltage (U_ZK) of the high-voltage intermediate circuit (110); and actuating (420) the discharge circuit (120) on the basis of the ascertained voltage (U_ZK).