Regenerative Motor Control Using Wheel and Crank Speed Differentials
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Solution Overview
Problem
Existing regenerative control techniques for power-assisted vehicles limit regenerative power recovery to specific riding states, such as brake operation or prescribed crank rotation values, missing opportunities for wider-range regenerative charging.
Innovation Solution
A regenerative controller for electric motors that uses sensors to detect wheel and crank speeds, enabling regenerative operation based on speed differentials, allowing for broader application of regenerative charging across various riding states without requiring intentional brake operation or specific crank rotation thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If regenerative control is performed only when the rider operates the brakes, then the control system is simple, but regenerative power recovery opportunities are limited
Solution Approach 1:
The regenerative control system dynamically adjusts its operation based on real-time detection of crank rotation speed and vehicle speed. The control unit continuously monitors these parameters and activates regenerative control when the crank rotation speed is below a first threshold and the vehicle speed is above a second threshold, creating a dynamic control strategy that adapts to varying riding conditions rather than relying on static brake operation detection
Solution Approach 2:
The system implements feedback control by using sensors to detect crank rotation speed and vehicle speed, then feeding this information back to the control unit which decides whether to activate regenerative control. This closed-loop feedback mechanism enables the system to automatically identify appropriate regenerative opportunities based on actual riding state, expanding power recovery beyond simple brake operation triggers
2Productivity
If regenerative control is performed when crank rotation amount is below a prescribed value, then regenerative charging is enabled in some states, but regenerative control is not performed when crank rotation amount is the prescribed number or higher
Solution Approach 1:
The system uses multiple threshold parameters (first threshold for crank rotation speed, second threshold for vehicle speed) to define regenerative control activation conditions. By changing and combining multiple parameters rather than relying on a single crank rotation threshold, the system achieves broader adaptability across different riding states including coasting, descending, and low-cadence pedaling scenarios
Solution Approach 2:
The regenerative control system is designed to function universally across multiple riding states by detecting both crank rotation speed and vehicle speed. It can activate regenerative charging during coasting (crank not rotating), descending (crank rotating slowly), and low-cadence pedaling, making the system versatile and applicable to a wide range of riding conditions rather than being limited to specific crank rotation ranges
3Productivity
If regenerative control is performed during coasting period, then power recovery opportunities increase, but it may cause discomfort to the rider
Solution Approach 1:
The system carefully selects and adjusts threshold parameters to ensure regenerative control activates only in appropriate conditions. By setting the first threshold for crank rotation speed and the second threshold for vehicle speed at optimal values, the system enables power recovery during coasting and descending while avoiding activation during normal pedaling, thus maintaining rider comfort
Solution Approach 2:
The dual-parameter feedback mechanism (monitoring both crank rotation speed and vehicle speed) provides accurate detection of rider intent and riding state. This feedback allows the system to distinguish between intentional coasting (where regeneration is appropriate) and normal pedaling (where regeneration should be avoided), thereby maintaining rider comfort while maximizing power recovery opportunities
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 increases the opportunities for regenerative power recovery, enhancing the efficiency of power-assisted vehicle operation by utilizing regenerative charging in more riding scenarios, thereby extending the riding distance on a single charge and improving riding comfort.
Implementation Method 1
the power generated by the motor can regeneratively charge the battery
Data Source
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AI summary
[Problem] To increase the opportunities for recovering regenerative power by wide-range regenerative control in various running states of a power-assisted vehicle. [Solution] A regenerative controller for an electric motor includes: a wheel rotation detection unit provided on a vehicle and detecting a rotation amount of a wheel that is driven via a crank rotated by human power; a crank rotation detection unit that detects a rotation amount of the crank; and a controller that calculates a first value based on the rotation amount of the wheel, a second value based on the rotation amount of the crank, and control information based on at least the second value among the first value and the second value for regenerative control of a power storage device regeneratively charged by an electric motor that supplies driving power to the wheel, the controller controlling a regeneration amount of the electric motor in accordance with the control information.