Rail Vehicle Coolant Pump Power Isolation During Emergency Braking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrically drivable vehicles, such as high-speed trains, face challenges in reliable electrodynamic braking during emergency braking due to interference signals in the three-phase AC on-board electrical system affecting the operation of coolant pumps, which are critical for cooling power semiconductors in current converters.
Innovation Solution
The implementation of a second on-board electrical system, preferably a DC voltage system decoupled from the three-phase AC system, ensures reliable power supply to coolant pumps, backed by an electrical charge storage device and connected via a DC chopper and inverter, to prevent cooling failure during prolonged emergency braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coolant pumps are connected to the three-phase AC on-board electrical system, then the system structure is simplified and ease of operation is improved, but interference signals compromise the reliability of coolant pump operation during emergency braking
Solution Approach 1:
The on-board electrical system is segmented into two independent parts: the three-phase AC system for general loads and a separate DC voltage system specifically for coolant pumps. This segmentation isolates the coolant pumps from interference signals in the AC system while maintaining operational simplicity through dedicated power supply architecture.
Solution Approach 2:
A DC voltage electrical system acts as an intermediary between the three-phase AC system and the coolant pumps. The DC system receives power from the AC system through controlled conversion (via DC chopper and inverter) and provides clean, interference-free power to the coolant pumps, mediating the connection while eliminating harmful interactions.
2Reliability
If a second on-board electrical system is introduced to power coolant pumps, then the reliability of cooling during emergency braking is improved, but the complexity of the electrical system increases
Solution Approach 1:
The DC voltage electrical system serves multiple functions: it powers the coolant pumps during normal operation, provides backup power through electrical charge storage devices during emergencies, and can be charged from the three-phase AC system. This multi-functionality justifies the added complexity by consolidating several critical functions into a single integrated system.
Solution Approach 2:
Electrical charge storage devices (batteries) are pre-charged during normal operation to provide backup power capacity. This beforehand cushioning ensures that coolant pumps can continue operating during emergency braking even if the main power supply fails, preventing cooling failure before it occurs.
3Reliability
If coolant pumps are individually fed via a separate electrical system, then the safety integrity level is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The electrical parameters for coolant pump power supply are changed from three-phase AC to DC voltage, and the voltage level is specifically adapted (e.g., 24V DC or other appropriate DC levels). This parameter change simplifies the control architecture and enables the use of solid-state controllers that are more reliable and easier to manufacture than AC motor control systems with interference susceptibility.
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 solution ensures continuous and reliable cooling of power semiconductors, reducing the risk of overheating and hazard situations by isolating coolant pumps from interference signals, thus enhancing the safety integrity level of the vehicle's electrical systems.
Implementation Method 1
connected via at least one battery charger to the output side of at least one DC chopper, in particular a DC/DC converter
Implementation Method 2
an inverter that couples the DC chopper and the three-phase AC on-board electrical system
Implementation Method 3
at least one coolant pump for pumping a coolant that cools the current converter
Implementation Method 4
The second on-board electrical system is preferably backed up by at least one electrical charge storage device
Data Source
AI summary
An electrically driveable vehicle, in particular a rail vehicle, includes an intermediate DC circuit, an in-vehicle, three-phase on-board electrical system fed by the intermediate DC circuit, at least one drive motor fed by a converter, and at least one coolant pump for pumping a coolant that cools the converter. In addition to the in-vehicle three-phase on-board electrical system, the vehicle also has a second on-board electrical system. The at least one coolant pump is connected to the second on-board electrical system.