HVDC Converter Energy-Based Braking Control for Overcharge Prevention
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Solution Overview
Problem
Conventional controllers for power dissipating arrangements in HVDC power transmission networks are slow and can lead to excessive charging of power converters during instantaneous power decreases, such as faults or load changes, which can cause damage.
Innovation Solution
A controller that determines parameters associated with the power converter, such as energy levels, to generate control signals for the power dissipating arrangement, specifically a dynamic braking system, to manage energy transfer and dissipate excess energy effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional controller based on DC voltage is used to control the power dissipating arrangement, then the control system is simple, but the response speed is slow and excessive charging of the power converter occurs
Solution Approach 1:
The controller determines an energy level of the power converter and compares it to a reference energy level to generate an energy difference signal before the power converter becomes excessively charged. This preliminary action allows the power dissipating arrangement to be activated in advance, preventing the harmful condition rather than reacting to it after it occurs.
Solution Approach 2:
The controller continuously monitors the energy level of the power converter and uses this feedback to adjust the control signal to the power dissipating arrangement. The energy difference between the actual and reference energy levels forms the basis for dynamic adjustment of the dissipation rate, creating a closed-loop control system that responds rapidly to changing conditions.
2Reliability
If the power dissipating arrangement responds slowly to power decreases, then the control system is simpler to implement, but the power converter suffers excessive charging and potential damage
Solution Approach 1:
By comparing the determined energy level to a reference energy level to generate an energy difference signal, the system takes preliminary protective action before the power converter reaches dangerous charge levels. This advance detection and response mechanism protects the power converter from excessive charging and potential damage.
Solution Approach 2:
The invention replaces conventional DC voltage-based control with an energy-level-based control system. This substitution enables more accurate monitoring of the power converter's actual energy state, allowing for precise control of the power dissipating arrangement to protect against excessive charging while maintaining system reliability.
3Measurement precision
If conventional DC voltage-based control is used, then the control method is straightforward, but it cannot quickly detect and respond to energy imbalances in the power converter
Solution Approach 1:
The invention substitutes DC voltage measurement with energy level measurement of the power converter. This replacement provides more precise detection of the converter's actual energy state, enabling accurate identification of energy imbalances. The energy level is determined by measuring capacitor voltages and calculating the corresponding energy, which directly reflects the converter's charging state.
Solution Approach 2:
The controller continuously determines the energy level and compares it to a reference level, creating a feedback mechanism that precisely detects energy imbalances. The energy difference signal provides real-time information about the converter's energy state, enabling rapid and accurate detection of conditions requiring intervention.
Data Source
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AI summary
There is provided a controller (200), and a method, for controlling a power dissipating arrangement (230) connected to a converter station (160), wherein the converter station (160) comprises a power converter (120) that is connected to a power transmission medium (130). The controller (200) is configured to: determine a parameter associated with the power converter (120); use the parameter to determine a control signal (203) for the power dissipating arrangement (230); and provide the control signal (203) to the power dissipating arrangement (230). The power dissipating arrangement (230) is configured to use the control signal (203) to control a switching of the power dissipating arrangement (230) to dissipate energy from the power transmission medium (130) and reduce a transfer of energy between the power transmission medium (130) and the power converter (120).