Rail Vehicle Traction Lock Control Signal Blocking Circuit
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Solution Overview
Problem
Existing traction lock systems in rail vehicles face challenges in ensuring high operational reliability and safety, particularly in preventing unintentional jerky movements during station stops, which can damage components and pose safety risks, with current solutions either disrupting power supply or risking damage to semiconductor switches during torque prevention.
Innovation Solution
A method and device that incorporate a control signal blocking circuit with a freely programmable FPGA module to manage test request signals and ensure orderly power converter shutdown, using redundant signal paths and self-testing to prevent damage to semiconductor switches, allowing for hardware-based locking without altering software or microcomputer algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hardware gate circuit is used to block control signals to the power converter, then operational reliability is improved, but the risk of damaging semiconductor switches increases due to uncoordinated control signals
Solution Approach 1:
The patent applies preliminary action by implementing a self-test function that checks the signal path between the control unit and the power converter before actual operation. The test request signal is sent through the same signal path that will carry control signals, allowing the system to detect potential failures in advance and prevent damage to semiconductor switches by identifying open circuits or other defects before they cause harm during normal operation.
Solution Approach 2:
The patent implements feedback by reading back the signal state from the control signal path and comparing it with the expected state. The readback channel monitors whether control signals are properly transmitted from the control unit through the signal path to the power converter, and if a discrepancy is detected (indicating a fault), the system can take corrective action to prevent damage to semiconductor switches while maintaining the hardware-based blocking function.
2Reliability
If standstill monitoring is used to detect and prevent unwanted movement, then safety is improved, but the response time is delayed until a jerk occurs
Solution Approach 1:
The patent applies preliminary action by continuously monitoring the signal path integrity through self-testing, rather than waiting for a jerk or movement anomaly to occur. The test request signal is periodically sent through the control signal path to detect open circuits or faults before they can cause unwanted movement, enabling the system to prevent safety issues before they manifest as physical problems.
3Reliability
If the main switch is opened to interrupt power supply at each station stop, then unwanted propulsion is prevented, but power supply to ancillary units is also eliminated
Solution Approach 1:
The patent extracts the traction blocking function from the main power switch by implementing a dedicated control signal blocking circuit in the control signal path. This separate hardware gate circuit specifically blocks control signals to the power converter without affecting the main power supply to ancillary units, isolating the safety function from the main power management and allowing selective blocking of only the traction-related control signals.
Data Source
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AI summary
Method for blocking the traction of a stationary rail vehicle, wherein a traction block (1) comprises a control signal blocking circuit (9) arranged in a control signal path (10) connecting a control unit (6) to a drive unit (22), wherein the control unit (6) generates a test request signal (13) depending on a traction block request signal (3) generated by a device (2) and received via a first signal path (5), which is fed via a second signal path (12) on the one hand to a freely programmable circuit (20) arranged in a section of the control signal path (10) connecting the control unit (6) and the control signal blocking circuit (9) and on the other hand, via a delay element (16), to the control signal blocking circuit (9) with a time delay.wherein the signal state of a section of the control signal path (10) located between the control signal blocking circuit (9) and the drive unit (22) is read back from the control unit (6) by means of a feedback channel (23), and wherein the freely programmable circuit (20) is configured to block control signals (8) generated by the control unit (6) when a traction lock request signal (3) is present, so that the drive unit (22) is not damaged.