Electric Safety Braking Device for Track-Bound Vehicles
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Solution Overview
Problem
Existing electric safety braking devices for track-bound vehicles are unreliable due to the risk of malfunction in emergency conditions, requiring large mechanical brakes that are costly, energy-intensive, and environmentally polluting, with limited controllability and independence from electrical disturbances.
Innovation Solution
An electric safety braking device with a control unit and semiconductor switches that vary resistance from infiniteness to theoretical zero, allowing controlled braking without mechanical assistance, and operating independently of electrical power supply malfunctions, using a combination of step-down and step-up switches and semiconductor devices like IGBTs to maintain constant braking torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a purely mechanical safety braking device is used, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the purely mechanical safety braking system with an electric braking system that uses the electric machine as a generator. The electric machine converts kinetic energy directly into electrical energy, which is then dissipated through resistors. This substitution eliminates the need for complex mechanical braking components while maintaining safety braking functionality, thereby reducing device complexity and cost.
Solution Approach 2:
The electric machine serves dual purposes: it acts as a motor during normal operation and as a generator during safety braking. By utilizing the same component for both propulsion and braking, the system eliminates the need for separate dedicated braking mechanisms, reducing overall system complexity while maintaining reliability.
2Force
If a large mechanical brake is used for safety braking, then braking force is improved, but weight and energy consumption increase
Solution Approach 1:
The patent replaces heavy mechanical brake components with an electric braking system that generates braking force through electromagnetic induction. The electric machine, when operated as a generator, produces electromagnetic torque that opposes rotation, providing effective braking force without the need for large mechanical brake assemblies, thereby reducing weight.
Solution Approach 2:
The system changes the operating parameters of the electric machine to achieve braking. By controlling the electrical resistance connected to the machine terminals and adjusting the generator mode operation, the system can vary braking force dynamically without being constrained by fixed mechanical brake capacity, enabling effective braking with lighter components.
3Force
If a large mechanical brake is used for safety braking, then braking force is improved, but energy consumption and environmental impact increase
Solution Approach 1:
The patent converts the harmful effect of kinetic energy that needs to be dissipated during braking into useful electrical energy. Instead of simply dissipating energy as heat through friction, the system generates electrical energy through electromagnetic induction, which can then be dissipated through resistors or potentially recovered and stored, thereby reducing overall energy consumption and environmental impact.
Solution Approach 2:
The replacement of mechanical friction-based braking with electric braking eliminates energy losses associated with friction and mechanical wear. The electric braking system converts kinetic energy directly into electrical energy with higher efficiency, reducing the total energy consumption required for safe braking operations.
4Ease of operation
If conventional electric braking with converter control is used, then controllability is improved, but reliability deteriorates due to component malfunction risk
Solution Approach 1:
The patent extracts the safety braking function from the conventional converter-controlled electric braking system. By using the electric machine as a self-contained generator that directly connects to resistors through simple switching devices, the system removes the complex converter control electronics that are prone to malfunction, thereby improving reliability while maintaining basic controllability through the switching mechanism.
Solution Approach 2:
The safety braking system is segmented into independent, simple components: the electric machine as generator, discrete switching devices, and resistors. This segmentation eliminates the need for complex integrated converter control, reducing the number of potential failure points while maintaining the ability to control braking through the switching devices.
5Device complexity
If resistance is kept constant in electric braking, then simplicity is improved, but controllability deteriorates at low speeds
Solution Approach 1:
The patent introduces dynamic resistance control into the electric braking system through switching devices that can connect or disconnect resistors based on operating conditions. This dynamic adjustment allows the system to maintain optimal braking torque across a wide speed range, including low speeds, by adapting the electrical resistance to match the generator output characteristics, thereby improving controllability without excessive complexity.
Solution Approach 2:
The system changes the electrical resistance parameter dynamically during braking operation. By controlling the switching devices to connect or disconnect resistors, the system can adjust the total resistance to maintain constant braking torque as speed varies, particularly improving performance at low speeds where constant resistance would be ineffective.
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 reliable, controlled, and efficient braking under emergency conditions, reducing the need for large mechanical brakes, maintaining braking torque at low speeds, and minimizing energy consumption and environmental impact.
Implementation Method 1
an electric permanent magnet machine configured to be connected to an electric power source through a converter configured to control said machine by Pulse Width Modulation for propulsion of the vehicle
Implementation Method 2
a resistive braking torque production assembly comprising a connection of electric terminals of the electric machine including at least one dissipative resistor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electric safety braking device for an electric track-bound vehicle comprising an electric permanent magnet machine (2) has a resistive braking torque production assembly comprising a connection (17) of terminals (14-16) of the electric machine through rectifying diodes (7) of a converter (4) including a dissipative resistor (18). A control unit (26) is configured to control means configured to vary the resistance of the connection (17) to keep this resistance infinitely high when not braking through said device and to accomplish braking through the device by varying this resistance to control the intensity of the current from the electric machine through said diodes and by that the braking torque applied to wheels through the device.