Motor Braking Control Using Capacitor Power After Supply Loss
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Solution Overview
Problem
Existing motor braking control methods fail to maintain effective braking when the power supply is removed, leading to uncontrollable voltage feedback and potential damage to motor components.
Innovation Solution
A motor control device comprising high-side and low-side switches, a capacitor, and a controller that stores kinetic energy in the capacitor after disconnecting from the external power supply, allowing for controlled motor braking by switching the low-side switches according to the supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the low-side switch is turned on to complete motor braking operation, then braking effectiveness is improved, but when power supply is removed the switch cannot remain turned on leading to loss of braking control
Solution Approach 1:
The capacitor stores energy in advance during motor operation, preparing power supply before the external power is disconnected. This preliminary energy storage enables the controller to maintain switch control capability during braking operation even after power disconnect, resolving the contradiction between braking reliability and power supply dependency.
2Loss of energy
If the low-side switch is turned off to stop braking, then power consumption is reduced, but the switch turns off at uncontrollable point in time causing voltage feedback to damage motor components
Solution Approach 1:
The controller continuously monitors the motor state and capacitor voltage level, using this feedback information to determine the optimal timing for turning off the low-side switch. This feedback mechanism ensures the switch is turned off at the precise moment when braking is complete and voltage feedback risk is eliminated, resolving the contradiction between energy efficiency and control precision.
3Duration of action of moving object
If additional components are added to maintain power supply during braking, then braking time is extended, but manufacturing cost and circuit size increase
Solution Approach 1:
The capacitor serves multiple functions: it acts as a power supply during braking when external power is disconnected, and also functions as part of the existing motor control circuitry. By making the capacitor multi-functional rather than adding a dedicated power supply system, the patent extends braking time without significantly increasing device complexity or manufacturing cost.
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 solution enables safe and efficient motor braking by maintaining power supply through stored kinetic energy, preventing voltage feedback and extending braking time without increasing manufacturing costs or circuit size.
Implementation Method 1
the voltage generated by the back electromotive force will be fed back to the power supply
Implementation Method 2
The capacitor is coupled to the set of high-side switches. The controller is coupled to the capacitor
Data Source
AI summary
A motor is coupled to a motor control device including a set of high-side switches, a set of low-side switches, a capacitor and a controller. The set of high-side switches and the set of low-side switches are coupled to the motor. The capacitor is coupled to the set of high-side switches. The controller is coupled to the capacitor, the set of high-side switches and the set of low-side switches. A method of braking the motor includes upon the motor being disconnected from an external power source, the controller receiving a supply voltage from the capacitor, turning on the set of low-side switches, turning off the set of high-side switches, and the controller switching the set of low-side switches according to the supply voltage.