HVDC Test Circuit Using Series Converter Modules
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Solution Overview
Problem
Existing test circuits for high-power semiconductor elements in HVDC systems are inflexible and dependent on mains frequency, limiting the ability to simulate real operating conditions and requiring significant hardware adjustments for different frequency applications.
Innovation Solution
A test circuit utilizing voltage-controlled power converter modules in series to create a flexible high-voltage source, combined with voltage-commutated power converter modules connected to a high-current transformer, allowing independent control of voltage and current for precise simulation of operating conditions, regardless of mains frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional test circuits with resonant circuits and high-current circuits are used, then high voltage and high current can be generated, but the test conditions are dependent on mains frequency and require hardware adjustments for different frequencies
Solution Approach 1:
The test circuit is divided into two independent series connections, each with its own voltage source. The first series connection (claim 1) generates high voltage through voltage-controlled converter modules, while the second series connection (claim 2) generates high current through voltage-commutated converter modules connected to a high-current transformer. This segmentation allows each connection to be optimized independently, eliminating the need for frequency-dependent resonant circuits and enabling frequency-independent operation.
Solution Approach 2:
The patent creates a universal test circuit that can operate at different frequencies (50 Hz, 60 Hz, or other frequencies) without requiring hardware adjustments. The voltage-controlled and voltage-commutated converter modules can be controlled to generate the required voltage and current waveforms at any frequency, making the test circuit adaptable to different application scenarios and eliminating the limitation of mains frequency dependency.
2Reliability
If back-to-back test equipment is used for high-power semiconductor elements, then comprehensive testing can be performed, but the equipment size and power output must be comparatively large
Solution Approach 1:
The patent segments the test equipment into two separate series connections with distinct functions. The first connection is optimized for high voltage generation with appropriate voltage rating, while the second connection is optimized for high current generation with appropriate current rating. This allows each connection to be sized appropriately for its specific function rather than requiring the entire system to be oversized for both voltage and current simultaneously, thereby reducing overall equipment size while maintaining testing comprehensiveness.
3Device complexity
If synthetic test circuits with separate high-current and high-voltage circuits are used, then only 1 to 2% of back-to-back system size is required, but the circuits are dependent on mains frequency and require parameter adjustments
Solution Approach 1:
The patent employs dynamically controllable converter modules in both series connections. The voltage-controlled converter modules in the first connection and the voltage-commutated converter modules in the second connection can be controlled to generate voltage and current waveforms at any frequency. This dynamic control capability allows the test circuit to adapt to different frequencies without parameter adjustments, eliminating the weakness of frequency dependency while maintaining the compact size advantage of synthetic test circuits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables flexible and independent setting of test conditions, allowing for comprehensive testing of high-power semiconductor elements across a wide voltage range without the need for frequent hardware adjustments, and reduces the size and complexity of test equipment.
Implementation Method 1
a plurality of voltage-controlled converter modules (16) connected in a first series (29) to one another in the high voltage source
Implementation Method 2
a plurality of voltage-commutated power converter modules (16) connected to a primary side (1P) of a high-current transformer (9)
Implementation Method 3
a plurality of voltage-commutated power converter modules (16) connected to a primary side (1P) of a high-current transformer (9), wherein a secondary side (2P) of the high-current transformer (9) is connected to the high-power semiconductor element (11)
Data Source
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AI summary
The invention relates to a test circuit (20) for a high-power semiconductor element (11) in power converters for high-voltage direct-current power transmission, said circuit comprising: a high-voltage circuit (22) with a terminal (31) for the high-power semiconductor element (11); and a high-voltage source (28) that can be connected to the high-power semiconductor element (11). The test circuit is intended to allow a particularly flexible setting of test conditions and to function in particular independently of the mains frequency. To achieve this, the high-voltage source (28) comprises a plurality of voltage-controlled power converter modules (16) connected in a first series (29).