HVDC Electronic Valve Topology for Thermal Stress Relief
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Solution Overview
Problem
The safety valve in high voltage direct current (HVDC) power transmission systems experiences high thermal stress due to continuous DC current flow, leading to a reduced lifespan and increased cooling needs, which is disadvantageous.
Innovation Solution
An electronic valve apparatus with multiple parallel chains of devices, each with an asymmetric transfer function, is used to distribute the thermal load, reducing the burden on individual devices and incorporating controllable switching devices and energy storage elements to manage current flow and detect faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single safety valve is used to block DC current flow in one direction, then the valve can effectively prevent reverse current flow, but the valve experiences high thermal stress and reduced lifespan
Solution Approach 1:
The patent divides the single safety valve into multiple parallel chains of devices (first device chain and second device chain), where each chain contains series-connected devices with asymmetric transfer functions. This segmentation distributes the thermal load across multiple devices, reducing stress on individual components while maintaining the overall current blocking capability of the safety valve system.
2Reliability
If a single safety valve carries full DC current continuously, then the valve provides adequate protection, but cooling requirements and thermal management complexity increase
Solution Approach 1:
By segmenting the current path into multiple parallel chains, each carrying a portion of the total DC current, the thermal load is distributed across multiple devices. This reduces the cooling requirements for each individual device and simplifies the overall thermal management system, while still providing adequate protection capability.
Solution Approach 2:
The patent combines multiple device chains in parallel to form a unified safety valve system that collectively handles the full DC current. The merged system provides redundant protection paths and distributes thermal loads, reducing the complexity of cooling requirements compared to a single valve handling all current.
3Temperature
If multiple parallel chains of devices are used to distribute thermal load, then thermal stress on individual devices is reduced, but the device complexity and number of components increases
Solution Approach 1:
The safety valve is segmented into multiple parallel chains, with each chain containing series-connected devices. This segmentation reduces thermal stress on individual devices by distributing the current load, while the modular chain structure allows for manageable complexity through standardized repeating units.
Solution Approach 2:
The patent changes the structural parameter from a single valve to multiple parallel chains, fundamentally altering how thermal load is distributed. This parameter change enables reduced thermal stress on individual devices while the systematic arrangement of chains keeps the overall complexity manageable through repetition of standardized units.
Data Source
AI summary
An electronic valve apparatus for a high voltage direct current, HVDC, power transmission system. The electronic valve apparatus includes a first device chain including a number of first devices connected in series between an input node and an output node. Each of the first devices has an asymmetric transfer function configured substantially to block current flow through the device in a first direction, and the first devices are connected such that they all block current flow in the same direction. The electronic valve apparatus also includes a second device chain including a number of second devices connected in series between the input node and the output node. Each of the second devices has an asymmetric transfer function configured substantially to block current flow through the device in a first direction, and the second devices are connected such that they all block current flow in the same direction.