Reactive Current Voltage Control in HVDC Power Modules
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Solution Overview
Problem
In high voltage direct current (HVDC) power transmission and reactive power compensation systems, existing technologies face challenges in efficiently managing reactive current demands, leading to increased material and power loss costs due to fixed target voltage references and high overvoltage requirements.
Innovation Solution
A controller for power electronic devices that adjusts the target voltage reference of energy storage devices based on reactive current demands, allowing for reduced module counts by increasing the target voltage in capacitive conditions and decreasing it in inductive conditions, using look-up tables or real-time calculations to optimize voltage settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed target voltage reference is used in power electronic devices, then the device can maintain stable operation, but the number of modules required increases leading to higher material costs and power losses
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed target voltage reference to a dynamic adjustment mechanism. The controller continuously monitors reactive current demand and adjusts the target voltage reference in real-time based on operating conditions. This dynamic approach allows the system to use fewer modules while maintaining stability, as the voltage reference adapts to match actual load requirements rather than maintaining a constant conservative value.
Solution Approach 2:
The patent implements parameter changes by modifying the target voltage reference value based on reactive current demand. The controller changes this critical parameter dynamically - increasing it when capacitive reactive current demand rises and decreasing it when inductive reactive current demand increases. This parameter adaptation enables the system to reduce module count while preserving reliable operation across varying operating points.
2Reliability
If the target voltage reference is increased to meet high overvoltage requirements, then the system can handle capacitive reactive current demand, but material costs and power loss capitalization increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the target voltage reference based on reactive current demand characteristics. When capacitive reactive current demand increases, the controller increases the target voltage reference to maintain overvoltage handling capability. When inductive reactive current demand increases, the controller decreases the reference. This dynamic parameter adjustment allows the system to meet overvoltage requirements only when necessary, reducing unnecessary power losses and material costs associated with always-designing for maximum overvoltage capability.
3Power
If more modules are used in the power electronic device, then the device can handle higher power demands, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies dynamics by implementing a flexible control strategy that adjusts the target voltage reference in real-time. This dynamic control enables fewer modules to handle higher power demands by optimizing their utilization. The controller monitors reactive current demand and adjusts operating parameters to maximize the efficiency and capacity of each module, reducing the total module count needed while maintaining or enhancing power handling capability.
Solution Approach 2:
The patent implements parameter changes that allow existing modules to operate more effectively across different power levels. By adjusting the target voltage reference based on reactive current demand, the system optimizes module utilization and can handle varying power demands without requiring additional modules. This parameter adaptation reduces device complexity and manufacturing costs while preserving power handling capability.
Data Source
Figure 1a
Figure 1b~1c
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AI summary
There is provided a controller for a power electronic device, the power electronic device comprising at least one module, the or each module including at least one switching element and at least one energy storage device, the or each switching element and the or each energy storage device in the or each module arranged to be combinable to selectively provide a voltage source, wherein the controller is programmed to adjust a target voltage reference of the or each energy storage device of the or each module responsive to a reactive current demand of the power electronic device.