Hybrid Vehicle Power Circuit for Stable DC-DC Input Without Battery

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Solution Overview

Problem

In hybrid power vehicles, the voltage output by a motor during power generation is not controlled when the power battery is disconnected, leading to unstable voltage fluctuations, which affects the DC-DC converter and results in significant losses due to uncontrollable rectification.

Innovation Solution

A power system that includes an engine, a power motor, a power battery, a DC-DC converter, an auxiliary motor, and a voltage stabilizing circuit, where the auxiliary motor is connected with the engine, power motor, and DC-DC converter, and the voltage stabilizing circuit stabilizes the DC output to the DC-DC converter, ensuring stable input voltage even when the power battery is disconnected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the power battery is disconnected, then the system can operate independently of the battery, but the voltage output by the motor during power generation becomes uncontrollable and fluctuates greatly

Engineering Contradiction:
Improveoperation independence from power batteryVSAvoidvoltage stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent introduces a voltage stabilizing circuit as an intermediary component between the motor and the DC-DC converter. This circuit actively regulates the voltage output from the motor, preventing fluctuations from reaching the DC-DC converter. The stabilizing circuit acts as a mediator that decouples the voltage instability issue from the rest of the system, allowing the power battery to be disconnected while maintaining stable operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If brake rectification mode is adopted, then the system can handle high counter electromotive force, but the output voltage cannot be controlled when power battery is disconnected

Engineering Contradiction:
Improvecounter electromotive force handling capabilityVSAvoidoutput voltage controllability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The voltage stabilizing circuit serves as an intermediary that sits between the brake rectification mode and the DC-DC converter. It allows the system to operate in brake rectification mode for handling high counter electromotive force while simultaneously regulating the output voltage to remain controllable and stable, even when the power battery is disconnected.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The voltage stabilizing circuit dynamically adjusts operating parameters such as switching duty cycle and rectification mode to maintain controlled output voltage. By changing these parameters in real-time based on system conditions, the circuit ensures that both high counter electromotive force and controlled output voltage can coexist.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If uncontrollable rectification is adopted, then the system can operate without voltage control, but the loss is very large

Engineering Contradiction:
Improveoperation simplicityVSAvoidrectification loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The voltage stabilizing circuit acts as an intermediary that maintains operational simplicity while reducing energy losses. It provides automatic voltage regulation without requiring complex manual intervention, and by stabilizing the voltage before it reaches the DC-DC converter, it prevents the large losses that would otherwise occur during uncontrolled rectification.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration maintains low-speed electric balance and smoothness, stabilizes the input voltage of the DC-DC converter, and ensures normal operation, reducing losses and improving vehicle performance.

Implementation Method 1

an auxiliary motor, connected with the engine and respectively connected with the power motor, the DC-DC converter and the power battery

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a voltage stabilizing circuit, connected between the auxiliary motor and the DC-DC converter and configured to perform voltage stabilizing treatment on the DC output to the DC-DC converter

Methodology Applied
Scientific EffectVoltage stabilization:

Implementation Method 3

a high voltage can be directly reduced by the DC-DC converter to a low voltage such as 12V so as to supply power to the low-voltage apparatus

Methodology Applied
Scientific EffectElectromagnetic transformation: Electromagnetic Induction

Data Source

PatentEP3604023B1Hybrid electric vehicle and power system thereof
Publication Date: 2024.05.29 BYD CO LTD
  • EP3604023B1 patent drawingFigure 1~2a
  • EP3604023B1 patent drawingFigure 2b
  • EP3604023B1 patent drawingFigure 2c

AI summary

This application discloses a hybrid power vehicle and a power system thereof, wherein the power system includes: an engine, outputting power to a wheel of the hybrid power vehicle through a clutch; a power motor, outputting driving force to the wheel of the hybrid power vehicle; a power battery, supplying power to the power motor; a DC-DC converter; an auxiliary motor, respectively connected with the engine, the power motor, the DC-DC converter and the power battery; and a voltage stabilizing circuit, connected between the auxiliary motor and the DC-DC converter and configured to perform voltage stabilizing treatment on the DC output to the DC-DC converter when the auxiliary motor generates power, thereby maintaining the low-speed electric balance and low-speed smoothness of the entire vehicle, stabilizing the input voltage of the DC-DC converter, and ensuring the normal work of the DC-DC converter.