Regenerative Motor Control Using Pedal-Speed Feedback
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Solution Overview
Problem
Conventional electrically assisted vehicle systems fail to perform regeneration control in conformity with the rider's intention, leading to inefficient energy collection and unnatural vehicle behavior due to inaccuracies in calculating regenerative braking forces based on unknown vehicle mass and frictional resistances.
Innovation Solution
A motor driving control apparatus that adjusts regenerative braking force based on vehicle acceleration, speed, and pedal-rotation converted speed, using a regeneration control unit to correct the braking force according to the coincidence degree of pedal-rotation converted speed with vehicle speed, and increasing the braking force when acceleration or speed exceeds predetermined values for enhanced energy collection and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If regenerative braking force is calculated using estimated mass and frictional resistances, then the system can perform automatic regeneration without rider input, but the calculation accuracy deteriorates due to unknown actual mass and resistance values
Solution Approach 1:
The system compares the calculated acceleration with the actual acceleration (derived from vehicle speed changes) to detect discrepancies. When the absolute value of acceleration difference exceeds a threshold, the system determines the vehicle is on an inclined road and adjusts regeneration control accordingly. This feedback mechanism eliminates the need for accurate mass and resistance estimates.
Solution Approach 2:
The patent introduces acceleration difference as an intermediary parameter to indirectly detect inclination conditions. Instead of directly calculating inclination resistance (which requires accurate mass and resistance data), the system uses acceleration difference as a mediator to infer road slope and adjust regeneration control.
2Productivity
If large regenerative braking force is applied to frequently charge the battery in urban running, then energy collection increases, but the rider must perform extra work when the braking force is excessive
Solution Approach 1:
The regenerative braking force is dynamically adjusted based on real-time running conditions. The system increases regeneration amount when acceleration difference is small (flat road, urban running) and decreases it when acceleration difference is large (steep incline, headwind). This dynamic adjustment optimizes energy collection while maintaining rider comfort.
Solution Approach 2:
The system changes the regeneration control parameter (regeneration amount) based on the acceleration difference threshold. When |actual acceleration - calculated acceleration| < threshold, larger regeneration is applied; when the difference exceeds the threshold, smaller regeneration is applied. This parameter change adapts the system to varying road conditions.
3Loss of energy
If regenerative braking force is increased to extend running distance, then energy collection improves, but vehicle stability deteriorates when the braking force conflicts with rider intention
Solution Approach 1:
The system continuously monitors acceleration difference as feedback to detect when regeneration conflicts with rider intention. When the difference exceeds the threshold, indicating the rider is actively controlling the vehicle (e.g., climbing a hill), the system reduces or suspends regeneration to maintain stability and align with rider intent.
Solution Approach 2:
The system preemptively adjusts regeneration control when acceleration difference indicates potential conflict with rider intention. By detecting the threshold condition beforehand, the system prevents instability before it occurs, rather than reacting after the problem arises.
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 enables regenerative control that aligns with the rider's intention, improving energy collection efficiency and maintaining stable vehicle speed, thereby extending the assisted running distance and ensuring safety by dynamically adjusting regenerative braking forces.
Implementation Method 1
causing the motor to perform regeneration when detecting, by the sensor, a brake operation by a rider to collect kinetic energy of the vehicle to the battery
Data Source
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AI summary
This motor driving control apparatus includes (A) a driving unit that drives a motor, and (B) a regeneration control unit that controls the driving unit so as to generate a regenerative braking force in accordance with a vehicle acceleration, a vehicle speed and a pedal-rotation converted speed that is obtained fromapedal rotation.