Motor Controller Regenerative Braking Slope Adjustment

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Solution Overview

Problem

Conventional regenerative braking systems in electric power-assisted vehicles often generate sudden and large regenerative braking forces when both brakes are used simultaneously, leading to rider discomfort and neglecting the relationship between regenerative braking force and rider comfort.

Innovation Solution

A controller system that adjusts the control coefficient based on input from brake sensors, gradually increasing the regenerative braking force according to the rider's instructions by differentiating the slopes of control coefficient change for single and dual brake states, allowing for customizable regenerative braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If regenerative braking force is increased when both brakes are used simultaneously, then regenerative charging efficiency is improved, but rider comfort deteriorates due to sudden large braking force

Engineering Contradiction:
Improveregenerative charging efficiencyVSAvoidrider discomfort
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control coefficient is increased gradually over time before reaching the maximum regenerative braking force, rather than applying full braking force immediately. This preliminary gradual action allows the rider to adapt to the regenerative braking effect, reducing shock and discomfort while still achieving efficient regenerative charging.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control coefficient is made dynamic and time-dependent, changing continuously from an initial value to a maximum value over a predetermined time period. This dynamic adjustment allows the regenerative braking force to evolve smoothly, balancing charging efficiency with rider comfort based on the braking duration and rider response.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If regenerative braking force is increased immediately, then energy recovery is improved, but shock during braking increases

Engineering Contradiction:
Improveenergy recoveryVSAvoidshock during braking
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The system applies a preliminary gradual increase in control coefficient before reaching maximum energy recovery levels. This preliminary phase allows the rider to experience a smooth transition into regenerative braking, reducing shock while still capturing kinetic energy effectively over the braking duration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The gradual increase in control coefficient acts as a cushioning mechanism before the full regenerative braking force is applied. This beforehand cushioning reduces the abruptness of the braking force, minimizing shock to the rider while preparing the system for maximum energy recovery.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Speed

If control coefficient increases rapidly, then regenerative braking response is improved, but rider comfort deteriorates

Engineering Contradiction:
Improvebraking response speedVSAvoidrider comfort
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The control coefficient follows a dynamic time-based progression rather than an instantaneous jump. This dynamic approach maintains responsive braking by achieving the maximum control coefficient within a predetermined time period, while the gradual transition preserves rider comfort through smooth force application.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary gradual adjustment of the control coefficient before reaching the target braking force level. This preliminary action maintains braking responsiveness by ensuring the control coefficient reaches its maximum value within a reasonable time frame, while avoiding abrupt changes that would compromise rider comfort.

Inventive Principle:
Principle #10Preliminary action

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 approach effectively suppresses shocks from sudden regenerative braking forces, enabling a more comfortable riding experience by allowing the regenerative braking force to increase in a manner responsive to the rider's intentions.

Implementation Method 1

a motor 105 that drives the vehicle

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

regenerative charging when only one of either of the brakes is used, is smaller than the electric regenerative braking force generated by the regenerative charging when both of the brakes are used together

Methodology Applied
Scientific EffectRegenerative charging: Electromagnetic Induction

Data Source

PatentEP2711231B1Controller for driving a motor and electric power-assisted vehicle
Publication Date: 2018.05.02 TAIYO YUDEN KK
  • EP2711231B1 patent drawingFigure 1
  • EP2711231B1 patent drawingFigure 2
  • EP2711231B1 patent drawingFigure 3

AI summary

A controller for driving a motor has: an input part that receives, from each of two brake sensors, a signal indicating a corresponding brake is in an ON state or a signal indicating that the brake is in an OFF state; a control coefficient computing part that increases a control coefficient relative to a regeneration target value along a first slope when a first signal indicating only one of the brakes is in an ON state is received from the input part, the control coefficient computing part increasing the control coefficient along a second slope when a second signal indicating both brakes are in an ON state is received from the input part, the second slope rising faster than the first slope; and a control part controlling driving of the motor in accordance with the regeneration target value and the control coefficient computed by the control coefficient computing part.