Reconfigurable Battery Voltage Control for Inverter-Free Regenerative Braking

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Solution Overview

Problem

Existing electric bicycle systems with regenerative braking face challenges due to the need for complex and costly inverters to manage voltage differences between the motor and battery, leading to significant energy losses and high production costs, limiting the adoption of regenerative braking technology.

Innovation Solution

A reconfigurable battery system with processor-controlled switches that dynamically reconfigure series-connected battery cells to adjust voltage output, eliminating the need for an inverter by ensuring the battery voltage is lower than the motor voltage during charging, allowing regenerative energy to be efficiently transferred back to the battery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inverter is used to manage voltage differences between motor and battery during regenerative braking, then regenerative charging can be achieved, but energy losses increase and production costs increase

Engineering Contradiction:
Improveregenerative braking functionalityVSAvoidenergy loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes the inverter component from the system by implementing a direct connection between the motor and battery. The motor directly charges the battery during regenerative braking without requiring voltage conversion through an inverter, thereby eliminating the energy losses and costs associated with inverter operation while maintaining regenerative charging functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If an inverter is used to manage voltage differences between motor and battery during regenerative braking, then regenerative charging can be achieved, but production costs increase

Engineering Contradiction:
Improveregenerative braking functionalityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent eliminates the inverter component from the system architecture, directly connecting the motor to the battery. This removal of the inverter significantly reduces production costs by eliminating the need to manufacture, import, and install expensive inverter equipment, while still enabling regenerative charging through direct motor-to-battery energy transfer.

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If battery voltage is kept lower than motor voltage during charging, then regenerative energy transfer is efficient, but voltage control complexity increases

Engineering Contradiction:
Improveenergy lossVSAvoidvoltage control complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements dynamic reconfiguration of battery cell connections using switches that can change the series/parallel arrangement of battery cells based on operating conditions. This dynamic reconfiguration allows the battery voltage to adapt and remain lower than motor voltage during regenerative charging, optimizing energy transfer efficiency while the control system manages the switching operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameters of the battery system by reconfiguring the connection topology of battery cells (series to parallel or vice versa) through controlled switches. This parameter change allows the battery voltage to be dynamically adjusted to maintain it below motor voltage during charging, enabling efficient regenerative energy transfer without requiring a fixed voltage ratio.

Inventive Principle:
Principle #35Parameter changes

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 solution enables efficient regenerative braking without the need for an inverter, reducing energy losses and production costs, while allowing for flexible voltage control and extended battery life through optimized charging and discharging cycles.

Implementation Method 1

a reconfigurable battery, having at least one bank of battery cells made from a statically joined plurality of series connected battery cells

Methodology Applied
Scientific EffectBattery (electricity): Battery (electricity)

Implementation Method 2

At least one processor controlled switch electrically reconfigures the battery cells by coupling a first voltage pole of a battery cell to the first electrical output connection and a second voltage pole of a battery cell to the second electrical output connection to provide a reconfigurable battery output voltage

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP2812992B1Reconfigurable battery
Publication Date: 2021.06.30 LEE CHONG UK
  • EP2812992B1 patent drawingFigure 1
  • EP2812992B1 patent drawingFigure 2~3
  • EP2812992B1 patent drawingFigure 4

AI summary

A reconfigurable battery has at least one bank of statically joined series connected battery cells, each cell including a positive and a negative pole. The poles connect through switches to respective output connections. Activating a set of processor controlled switches reconfigures at least some of the battery cells into a configuration to provide a voltage across the output connections. The output battery voltage may vary intermediately between zero volts and the maximum voltage produced by the series connected battery cells. An alternative configuration of switches divides groups of series connected battery cells into separate battery banks that permit other battery cell configurations. Duty cycle modulation of the switches allows intermediate control of output voltage with reduced switching transients. Reconfigurable battery cells used in combination with an electric motor permit selectable speed control and battery regeneration schemes matched to motor output.