Bipolar Power Converter Control With Unequal Active Power Commands
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Solution Overview
Problem
In bipolar power conversion systems where the first-pole and second-pole power converters have different functions and characteristics, such as self-excited and separately-excited types, existing technologies fail to operate the system appropriately due to these differences.
Innovation Solution
The system employs a control device that sets different active power command values for the first-pole and second-pole power converters, allowing for tailored operation based on their distinct functions and characteristics, and includes a common control device to manage communication between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the same active power command value is applied to both first-pole and second-pole power converters, then the control system is simple, but the system cannot operate appropriately according to the different functions and characteristics of each converter type
Solution Approach 1:
The patent applies local quality by setting different active power command values for the first-pole and second-pole power converters based on their specific characteristics. The control device identifies the converter types (self-excited or separately-excited) and assigns appropriate command values to each pole, allowing each converter to operate optimally according to its local properties rather than applying a uniform control strategy to both.
2Loss of energy
If different active power command values are set for first-pole and second-pole power converters, then the system operates more appropriately according to converter differences, but the control system becomes more complex
Solution Approach 1:
The patent implements parameter changes by adjusting the active power command values as control parameters based on the identified converter types. The control device modifies these parameters dynamically - setting specific command values for self-excited converters versus separately-excited converters - to optimize power loss while maintaining manageable system complexity through automated parameter selection.
3Ease of manufacture
If the bipolar HVDC system uses facilities with different installation timings and types, then the system can be established incrementally, but the first-pole and second-pole HVDC have different functions and characteristics that complicate operation
Solution Approach 1:
The patent applies dynamics by implementing a flexible control strategy that adapts to the specific configuration of each pole. The control device dynamically identifies the converter types and adjusts the active power command values accordingly, allowing the system to operate effectively whether poles are installed simultaneously or at different times, and whether they use different converter types (self-excited or separately-excited).
Data Source
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AI summary
In a power conversion system (10) according to one embodiment, a first power converter (11) is connected between a first AC power system (9), and a first DC main line (13A) and a DC return line (13B). A second power converter (12, 15) is connected between the first AC power system (9), and the DC return line (13B) and a second DC main line (13C). A first control device (33) controls the first power converter (11) in accordance with a first active power command value. A second control device (34) controls the second power converter in accordance with a second active power command value. A common control device (32) sets the first active power command value and the second active power command value by distributing a command value of total active power output from the entire power conversion system (10) to the first AC power system (9). The common control device (32) makes the first active power command value and the second active power command value different from each other.