Super Capacitor Module for Elevator Emergency Rescue and Energy Recovery
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Solution Overview
Problem
Current lift systems face two major issues: they are unusable during emergencies like power failures, posing safety risks to passengers, and they have low operation efficiency due to energy dissipation during braking, with rechargeable batteries offering limited reliability and energy-saving inefficiencies.
Innovation Solution
A device utilizing a super-capacitor module for emergency backup power and energy management, including a DC-DC converter, DC-AC inverter, switch circuit, and energy management system to store and reuse braking energy, ensuring stable power supply and efficient energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rechargeable battery is used as backup supply for emergency stopping-at-right-floor-level, then the lift can operate during power failure, but the service lifetime is limited and charging time is long
Solution Approach 1:
The patent changes the energy storage parameter from rechargeable battery to super-capacitor module, which has different electrical characteristics including higher power density and faster charging/discharging rates, thereby resolving the contradiction between emergency operation capability and service lifetime
Solution Approach 2:
The patent replaces the electrochemical battery system with a super-capacitor electrical energy storage system, utilizing different physical principles (electrical double-layer capacitance vs. electrochemical reactions) to achieve improved reliability and duration for emergency lift operation
2Reliability
If braking energy is dissipated by braking resistor, then the DC bus voltage can be controlled, but energy is wasted
Solution Approach 1:
The patent converts the harmful effect of excessive DC bus voltage into a beneficial energy storage opportunity by directing braking energy to charge the super-capacitor module, thereby simultaneously controlling voltage and recovering energy that would otherwise be wasted
Solution Approach 2:
Instead of discarding braking energy through the resistor, the patent recovers this energy by routing it through the DC-DC converter to charge the super-capacitor module, transforming waste energy into useful stored energy for later use
3Loss of energy
If feedback energy is output to power grid via inverter, then energy is recovered effectively, but harmonics pollute the power grid
Solution Approach 1:
The patent introduces the super-capacitor module as an intermediary energy storage device between the braking energy source and the power grid, allowing energy recovery without direct grid connection that would cause harmonic pollution
Solution Approach 2:
The patent extracts the energy recovery function from the grid-connected inverter system and places it in an isolated super-capacitor charging system, separating the energy storage function from grid interaction to eliminate harmonic pollution while maintaining recovery efficiency
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
Provides reliable emergency power and efficient energy reuse, enabling lifts to safely stop at the nearest floor during power failures and optimizing energy usage by storing and reusing feedback energy.
Implementation Method 1
a super-capacitor module configured to store energy comprising backup energy for emergency stopping-at-right-floor-level of the lift and feedback energy generated by a traction motor during braking
Implementation Method 2
a DC-DC converter connected to the super-capacitor module and a motor drive for driving the traction motor of the lift, and configured to convert a voltage level of the super-capacitor module into a voltage level of a DC bus of the motor drive
Implementation Method 3
a DC-AC inverter connected to the DC-DC converter, and configured to convert DC power output from the DC-DC converter into AC power
Data Source
AI summary
An elevator automatic rescue and energy-saving control method, the method comprising: when the power grid supplies power normally, selecting a single current in a three-phase power grid (9) as an AC power supply for an elevator control system (10); controlling a DC-DC converter (2) to charge the super capacitor module (1) connected to the DC-DC converter to a specified standby electric energy level; and when the power grid is suddenly interrupted, selecting to use the electric energy stored in the super capacitor module (1) as a rescue electric energy for a traction motor (7) and the elevator control system (10). The described method uses a super capacitor module, so that a stable and reliable elevator rescue power supply is provided when the power grid is suddenly interrupted, and the regenerative electric energy dissipated during elevator braking operation is stored and utilized during elevator operation, thereby conserving energy.