Electric Motor Controller Regenerative Braking Startup
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Solution Overview
Problem
Permanent magnet brushless electric motors experience jitter phase oscillations after shutdown, making it difficult to detect when the rotor has completely stopped, leading to potential reverse startup and the need for undesirable delays before restarting.
Innovation Solution
Implementing a method that uses regenerative braking to capture kinetic energy and store it in a capacitor, with a timer to ensure the rotor has stopped, allowing immediate startup without delays by setting a flag in the motor controller's memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a time delay is built in before start up routines are carried out to ensure the rotor is stationary, then the motor can be started safely without reverse direction, but the start up time is increased and productivity is reduced
Solution Approach 1:
The patent replaces the mechanical/time-based delay system with an electrical sensing system. Instead of waiting a fixed time period to ensure the rotor is stationary, the system uses the rotor position sensor to actively detect the rotor's state and determine when it has come to rest, allowing immediate startup once the condition is confirmed.
Solution Approach 2:
The patent implements feedback by continuously monitoring the rotor position sensor signal to detect when the rotor has stopped oscillating. The controller receives feedback about the rotor's motion state and uses this information to determine the appropriate time to initiate startup routines, eliminating the need for predetermined delay periods.
2Use of energy by moving object
If regenerative braking is performed to recapture kinetic energy, then energy efficiency is improved, but the system complexity increases due to additional control mechanisms
Solution Approach 1:
The patent makes the motor controller multi-functional by having it perform both the regenerative braking energy recapture function and the rotor position detection function. The same controller that manages motor operation also monitors the rotor position sensor and determines when startup is appropriate, eliminating the need for separate dedicated systems for each function.
Solution Approach 2:
The patent merges the energy management function (regenerative braking) with the control function (startup timing determination) into a single integrated process. The controller simultaneously manages energy recapture from the rotor and monitors rotor position to determine startup readiness, combining multiple functions into one unified system.
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
Enables immediate motor startup without unnecessary delays, minimizes energy consumption, and prevents potential damage by monitoring capacitor voltage during regenerative braking.
Implementation Method 1
performing regenerative braking to recapture kinetic energy from the rotor as electrical energy
Implementation Method 2
The recaptured electrical energy may be stored in a capacitor
Data Source
AI summary
A method is described for controlling an electric motor having a rotor. The method is carried out after a shutdown of the motor has been initiated. The method includes starting a timer in a motor controller, performing regenerative braking to recapture kinetic energy from the rotor as electrical energy, and using the recaptured electrical energy from the regenerative braking to power the motor controller. If the timer in the motor controller exceeds a predetermined timer value, a flag is set in memory in the motor controller to indicate that the motor has stopped.