E-Bike Drive Power Mapping for Motor Overheating Protection
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Solution Overview
Problem
Existing electric bicycle systems lack effective methods to prevent motor overheating, leading to potential damage, reduced service life, and abrupt shutdowns without warning, which negatively impact user experience.
Innovation Solution
A method that utilizes an overheating protection map in the control unit to determine permissible maximum power based on temperature and gradient, adjusting power output to prevent overheating, with considerations for battery state, path incline, ambient temperature, and GPS position, ensuring gradual power reduction before critical temperatures are reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor is switched off at a lower switch-off temperature to protect the motor, then the motor reliability is improved, but the user experience deteriorates due to abrupt shutdowns without warning
Solution Approach 1:
The control unit performs preliminary action by gradually reducing motor power before the switch-off temperature is reached. This preliminary power reduction serves as a warning to the user, allowing them to adjust their riding behavior to prevent abrupt shutdowns while still protecting the motor from overheating damage.
Solution Approach 2:
The system applies preliminary anti-action by reducing motor power in advance before critical temperatures are reached. This counteracts the potential harmful effect of abrupt shutdowns by preparing the system gradually, thereby protecting both the motor and user experience simultaneously.
2Ease of operation
If the motor power is limited from a temperature lower than cut-off temperature, then the user experience is improved by providing warning, but the motor productivity decreases due to restricted power output
Solution Approach 1:
The control unit dynamically adjusts motor power based on real-time temperature measurements. Instead of applying a fixed power limitation, the system continuously adapts power output to current thermal conditions, thereby minimizing productivity loss while still providing early warning and protection capabilities.
Solution Approach 2:
The system changes operational parameters dynamically by adjusting motor power as a function of temperature. Power reduction is applied progressively as temperature increases, rather than applying a constant limitation, thereby optimizing the balance between user experience and motor productivity throughout the operating range.
3Productivity
If the electric drive operates at high temperature to maintain performance, then the productivity is improved, but the motor reliability deteriorates due to risk of damage and fire
Solution Approach 1:
The control unit implements continuous feedback monitoring of motor temperature and adjusts power output accordingly. This closed-loop control ensures the motor operates within safe temperature boundaries while maximizing performance, automatically reducing power when temperature approaches critical levels to prevent damage or fire hazards.
Solution Approach 2:
The system applies beforehand cushioning by implementing progressive power reduction before critical temperatures are reached. This creates a thermal buffer that prevents the motor from entering dangerous temperature zones, cushioning against potential damage or fire while still allowing high-performance operation within safe boundaries.
Data Source
AI summary
A method for operating a drive of an electric bicycle with a determination of an overheating protection of an electric drive is disclosed. The method includes (i) receiving and/or reading status data, wherein the status data comprises a temperature of the electric drive and a temperature gradient of the electric drive, (ii) receiving an overheating protection map and/or reading the overheating protection map from a memory, wherein the overheating protection map indicates a permissible maximum power of the electric drive as a function of the status data, (iii) determining a permissible maximum power from the overheating protection map by way of the status data, and (iv) outputting a power which is at most the permissible maximum power of the electric drive.