Lifting Magnet Controller Using H-Bridge Energy Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control systems for lifting magnets in scrap metal handling suffer from high voltage spikes, leading to arcing and component wear, requiring expensive and oversized materials, and result in inefficient energy dissipation as a resistor or varistor is used for discharge, which prolongs the 'Drop' phase and reduces system efficiency.
Innovation Solution
The system returns lifting magnet energy to the DC generator during the 'Lift' phase, utilizing a Transient Voltage Suppressor (TVS) to control voltage and employing solid-state devices for switching, allowing for faster discharge and reducing voltage spikes, thereby extending the lifespan of components and reducing 'Drop' time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a resistor or varistor is used to discharge the lifting magnet's energy, then the voltage spike is reduced, but the discharge time increases and energy is wasted as heat
Solution Approach 1:
The patent converts the harmful voltage spike and stored magnetic energy into a beneficial resource by feeding it back to the DC generator. The lifting magnet's energy is transformed back into electrical energy that can be returned to the generator, eliminating waste and reducing discharge time while controlling voltage spikes through the generator's inherent electrical characteristics
Solution Approach 2:
Instead of discarding the lifting magnet's stored energy through resistive dissipation, the system recovers this energy by connecting the lifting magnet back to the DC generator during the discharge phase. This allows the energy to be reused, reducing both discharge time and energy waste
2Object-affected harmful factors
If a resistor or varistor is used to discharge the lifting magnet's energy, then the voltage spike is reduced, but energy is wasted and system efficiency decreases
Solution Approach 1:
The patent converts the harmful voltage spike and stored magnetic energy into a beneficial resource by feeding it back to the DC generator. The lifting magnet's energy is transformed back into electrical energy that can be returned to the generator, eliminating waste and reducing discharge time while controlling voltage spikes through the generator's inherent electrical characteristics
Solution Approach 2:
Instead of discarding the lifting magnet's stored energy through resistive dissipation, the system recovers this energy by connecting the lifting magnet back to the DC generator during the discharge phase. This allows the energy to be reused, reducing both discharge time and energy waste
3Speed
If high resistance resistor or high breakdown voltage varistor is used, then the discharge speed increases, but voltage spikes increase causing arcing and component wear
Solution Approach 1:
The DC generator acts as an intermediary between the lifting magnet and the electrical circuit during discharge. Instead of using a passive resistor or varistor that creates voltage spikes, the generator's electrical characteristics provide a controlled path for energy dissipation, enabling fast discharge without harmful voltage spikes or arcing
4Reliability
If the lifting magnet is discharged through a resistor, then the discharge is controlled, but the voltage decays with current leading to longer discharge time
Solution Approach 1:
The patent changes the electrical parameters of the discharge circuit by connecting the lifting magnet to the DC generator instead of using a fixed resistor. This allows the discharge characteristics to be dynamically controlled through the generator's electrical parameters, achieving both controlled discharge and reduced discharge time
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 approach minimizes voltage spikes, increases the useful life of lifting magnets and associated components, and shortens 'Drop' times, enhancing production efficiency by utilizing a constant voltage source for discharge, thus reducing energy wastage and prolonging component lifespan.
Implementation Method 1
the lifting magnet energy produced during the 'Lift' phase is returned to the DC generator which in turn converts it back into mechanical energy
Implementation Method 2
a Transient Voltage Suppressor (TVS) is provided to control DC generator maximum voltage when current is reversed in the DC generator
Implementation Method 3
A DC current energizes the lifting magnet in order to attract and retain the magnetic materials to be displaced
Implementation Method 4
a magnetic field in the lifting magnet of the same magnitude but in an opposite direction of the residual magnetic field is produced that the two fields cancel each other
Data Source
AI summary
A magnet controller supplied by a DC generator controls a lifting magnet. Four transistors, forming an H bridge, allow DC current to flow in both directions in the lifting magnet. During “Lift”, full voltage is applied to the lifting magnet. During “Drop”, reverse voltage is applied briefly to demagnetize the lifting magnet. At the end of the “Lift” and the “Drop”, most of the lifting magnet energy is returned to the DC generator. A transient voltage suppressor protects against voltage spike generated when current reverses in the generator.