Dual-Motor E-Bike Control with Master-Slave Output Coordination
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Solution Overview
Problem
Existing electric bicycle motor architectures face issues with stability during high-speed cruising and inefficient power distribution due to the placement of the battery and center of gravity, particularly in front-wheel and rear-wheel driving systems.
Innovation Solution
A dual-controller system is implemented, where the front and rear driving motors are controlled by separate devices that perform a master-slave query to determine a master controller, allowing dynamic adjustment of motor output based on sensing information for improved stability and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a front-wheel driving architecture is used, then the battery can be placed on the rear half of the electric bicycle, but the motor cannot effectively apply force when the center of gravity is behind during climbing
Solution Approach 1:
The patent divides the driving system into two independent parts: a front-wheel driving motor and a rear-wheel driving motor, each controlled by separate controllers. This segmentation allows the system to overcome the limitation of single-wheel drive by providing dual-wheel drive capability, enabling effective force application regardless of center of gravity position during climbing while maintaining battery placement flexibility.
2Power
If a rear-wheel driving architecture with in-wheel motor is used, then the output of the rear-wheel motor can be increased due to center of gravity distribution, but the stability is poor during cruising or high-speed cruising in urban areas
Solution Approach 1:
The patent implements independent control of front and rear driving systems through separate controllers that can operate independently or cooperatively. During cruising or high-speed cruising, the front driving motor can be activated to share the driving burden with the rear motor, improving stability while maintaining the high power output capability of the rear-wheel drive system when needed.
3Stability of the object's composition
If two separate driving devices control front and rear driving motors, then the stability of high-speed cruise is improved, but the device complexity increases
Solution Approach 1:
The patent merges the control logic of two driving systems into a coordinated master-slave controller architecture. The master controller manages overall system coordination, power distribution, and communication, while the slave controller executes specific motor control tasks. This merging approach maintains the stability benefits of dual independent control while reducing overall system complexity through integrated control management.
Solution Approach 2:
The master controller performs multiple functions including coordinating front and rear driving motors, managing power distribution from the battery, handling communication between controllers, and implementing safety monitoring. This multi-functionality consolidates what would otherwise require separate control systems, reducing device complexity while maintaining high-speed cruise stability.
4Ease of manufacture
If a master-slave query operation is implemented between front and rear driving devices, then the cost of the driving device is reduced, but the control system complexity increases
Solution Approach 1:
The master-slave query operation enables the control system to automatically determine the master controller role during initialization without requiring external configuration or complex hardwired communication circuits. The controllers autonomously negotiate their roles through a simple query protocol, reducing manufacturing cost while implementing the necessary control hierarchy through self-organization.
Data Source
AI summary
A motor driving system and a motor driving method adapted to an electric bicycle are provided. The motor driving system includes a sensing device, a front driving motor, a rear driving motor, a front driving device, and a rear driving device. The sensing device generates sensing information. The front driving device drives the front driving motor according to the sensing information. The rear driving device drives the rear driving motor according to the sensing information. When the motor driving system is powered-up, the front driving device and the rear driving device respectively perform a master-slave query operation to each other, and it is determined that one of the front driving device and the rear driving device includes a master controller according to a result of the master-slave query operation.