Switching Valve Dynamic Target Voltage for Module Loss Tolerance
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Solution Overview
Problem
Existing switching valves in voltage source converters for HVDC transmission and reactive power compensation often fail to maintain reliable operation when the number of healthy modules decreases, leading to potential system trips and increased capital and operational expenditures.
Innovation Solution
A switching valve configuration with a plurality of modules, each containing at least one switching element and an energy storage device, is controlled by a regulator that selectively adjusts the target voltage of each energy storage device based on the number of healthy modules. This approach allows the switching valve to maintain operation without triggering a system trip, even when the number of healthy modules decreases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of healthy modules decreases, then the reliability of the switching valve deteriorates, but the system traditionally triggers a trip instead of continuing operation
Solution Approach 1:
The patent implements dynamic adjustment of target voltage for energy storage devices based on the number of healthy modules. The regulator continuously adapts the target voltage parameter as modules fail or are taken offline, allowing the switching valve to maintain stable operation across varying operational conditions rather than having a fixed operating point that triggers trips when conditions change.
Solution Approach 2:
The core invention changes the target voltage parameter of energy storage devices dynamically based on the count of healthy modules. When modules are removed from service, the regulator adjusts the target voltage parameter to compensate for the reduced number of modules, maintaining proper energy distribution and preventing system trips that would otherwise occur due to parameter violations.
2Reliability
If redundant modules are added to maintain operation when healthy modules decrease, then reliability improves, but capital and operational expenditure increase
Solution Approach 1:
Instead of adding more physical redundant modules, the invention changes the operational parameters (target voltage) of existing energy storage devices to compensate for module losses. This parameter-based compensation allows the system to maintain reliability with fewer physical components, reducing both capital expenditure on additional modules and operational expenditure on their maintenance.
Solution Approach 2:
The invention creates a virtual redundancy through parameter adjustment rather than physical redundancy. By dynamically adjusting the target voltage parameter, the system effectively replicates the functional capacity of failed modules through control algorithm modifications, eliminating the need for physical duplicate modules to provide backup capacity.
3Ease of operation
If the target voltage of energy storage devices is kept fixed, then control simplicity is maintained, but the switching valve cannot adapt to reduced module conditions
Solution Approach 1:
The regulator transitions from a static control approach with fixed target voltage to a dynamic control approach where the target voltage parameter automatically adjusts based on the number of healthy modules. This dynamic adaptation maintains control simplicity from the operator's perspective while internally adapting parameters to ensure reliable operation under varying module conditions.
Solution Approach 2:
The system implements feedback control by continuously monitoring the number of healthy modules and automatically adjusting the target voltage parameter in response. This closed-loop feedback mechanism maintains reliability by detecting module failures and compensating through parameter adjustment, while keeping the control system transparent and simple to operate without requiring manual reconfiguration.
Data Source
AI summary
There is provided a switching valve for a voltage source converter, the switching valve comprising a plurality of modules, each module including at least one switching element and at least one energy storage device, each switching element and each energy storage device in each module arranged to be combinable to selectively provide a voltage source, the switching valve including a regulator programmed to selectively control the switching of the switching elements to select one or more of the modules to contribute a respective voltage to a switching valve voltage, wherein the regulator is programmed to selectively regulate an energy stored in each energy storage device by controlling the switching of the switching elements to regulate a voltage of each energy storage device towards a target voltage, and the regulator is programmed to vary the target voltage of each energy storage device as a function of a number of healthy modules.