Regenerative Braking Control for Hybrid Vehicle Battery

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Solution Overview

Problem

The deterioration of electricity storage devices in hybrid vehicles is accelerated by high current charge and discharge cycles and frequent power variations, which existing technologies fail to adequately address.

Innovation Solution

A charging/discharging control system that includes a motor/generator, an electricity storage device, an AC/DC conversion unit, and a control device, which restricts the magnitude of DC power from regenerative braking to suppress the deterioration of the electricity storage device by adjusting the supply current based on the charge state and braking period.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high current charge and discharge cycles are used to meet power demands, then the productivity and power response are improved, but the electricity storage device deteriorates faster

Engineering Contradiction:

Improvepower response capabilityVSAvoidelectricity storage device lifespan

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent dynamically changes the charge/discharge current parameters based on the operating conditions. The control device adjusts the current magnitude according to the charge state (SOC) of the electricity storage device, vehicle speed, and power demand, thereby optimizing both productivity and reliability under different operating conditions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic control of charge/discharge operations. The control device continuously monitors the charge state and adjusts the current profile in real-time, transitioning between different charge/discharge rates based on immediate system conditions, which prevents static high-current operation that causes deterioration

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If frequent charge and discharge operations are performed to respond to power variations, then the adaptability to power demands is improved, but the deterioration of the electricity storage device accelerates

Engineering Contradiction:

Improveresponse to power variationsVSAvoidelectricity storage device durability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements periodic charge/discharge cycles with varying intensity. The control device schedules charge/discharge operations based on predicted power demands and current state, creating optimized periodic patterns that meet adaptability requirements while preventing excessive frequency that would cause deterioration

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies partial charge/discharge actions rather than always operating at maximum capacity. The control device determines appropriate current levels based on actual power needs and state constraints, applying only the necessary charge/discharge magnitude required, thereby reducing unnecessary stress on the electricity storage device

Inventive Principle:

Principle #16Partial or excessive action

3Use of energy by moving object

If regenerative braking charges the electricity storage device at high power, then the energy recovery efficiency is improved, but the charge state becomes unstable and causes deterioration

Engineering Contradiction:

Improvebraking energy recoveryVSAvoidcharge state stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent implements feedback control for regenerative braking charging. The control device continuously monitors the charge state during regenerative braking and adjusts the charging current in real-time based on the measured SOC, preventing excessive or unstable charge states while maximizing energy recovery within safe operating limits

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies beforehand cushioning by setting upper limits on charge state during regenerative braking. The control device pre-establishes maximum charge thresholds and adjusts charging parameters in advance to prevent the charge state from becoming too high or unstable, thereby cushioning against potential deterioration from extreme charging conditions

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 system effectively suppresses the deterioration of the electricity storage device by controlling the charge and discharge processes, reducing the risk of rapid capacity loss and extending the device's lifespan.

Implementation Method 1

an AC (alternating current)/DC (direct current) conversion unit for performing AC/DC conversion processing between the AC power of the motor/generator and the DC power of the electricity storage device

Methodology Applied

Scientific EffectAC/DC conversion:

Data Source

PatentUS9580067B2Charging/discharging control system for electricity storage device

Publication Date: 2017.02.28 PANASONIC ENERGY CO LTD

AI summary

Charging/discharging control system for an electricity storage device includes motor/generator, electricity storage device, AC/DC conversion unit for performing AC/DC conversion processing between the AC power of motor/generator and the DC power of electricity storage device, and control device for controlling the charge and discharge of electricity storage device via AC/DC conversion unit. During charge control, in accordance with the charge state of electricity storage device, control device restricts the magnitude of the DC power that is obtained by converting the generation power generated by the regenerative braking of motor/generator at the deceleration and is supplied to electricity storage device.