Electric Bicycle Motor Theft Deterrent Using Generator Mode Braking
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Solution Overview
Problem
Traditional lock devices for electric bicycles are ineffective in preventing theft, especially when the battery is removable, as thieves can still break the lock and steal the bike without the battery.
Innovation Solution
A theft deterrent system for electric bicycles with three-phase motors without a freewheel, which uses the motor in a generator mode to power a control circuit, short-circuiting specific phases to create an increased braking force when the battery is removed, and storing energy in a capacitor to enhance braking when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lock devices are used to protect the electric bicycle, then the bicycle structure remains simple and easy to operate, but the theft protection effectiveness is insufficient
Solution Approach 1:
The invention converts the harmful effect of motor rotation (which a thief would use to ride away) into a beneficial braking force. When the motor is rotated without battery power, the control circuit activates electromagnetic braking by short-circuiting motor phases, transforming the thief's attempted movement into a force that opposes and prevents theft.
Solution Approach 2:
The system uses the motor itself as both the power source and the braking mechanism. The motor's rotation during attempted theft generates electrical energy that powers the control circuit, which then activates the motor's electromagnetic braking function. The system serves itself by using the theft attempt's energy to counteract the theft.
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 effectively deters theft by creating a strong electromagnetic braking effect that increases with motor speed, making it difficult for thieves to ride the bike away, and can be powered without a battery, ensuring continuous operation and increased security.
Implementation Method 1
using the motor in a generator mode to power a control circuit in an initial phase of rotating the motor through motion of the vehicle
Implementation Method 2
connecting by the control circuit first and second phases of the three-phase motor continuously to a first power supply line, whereby the first and second phases are short-circuited and cause an increased braking force of the motor
Implementation Method 3
storing energy produced by the motor in a capacitor of the control circuit
Data Source
AI summary
The invention relates to a method for deterring theft of a vehicle having a three-phase electric motor without a freewheel (10), comprising the steps of using the motor in a generator mode to power a motor control circuit (14) in an initial phase of rotating the motor through motion of the vehicle; and, when the power supply level of the control circuit reaches a first threshold (Vmin), connecting by the control circuit first and second phases (b, c) of the three-phase motor continuously to a first power supply line (Vss), whereby the first and second phases are short-circuited and cause an increased braking force of the motor. During this time, the third phase of the motor may be connected to continue to supply energy to the control circuit.