Rectangular Control Signal Traction Converter Circuit
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Solution Overview
Problem
Traction converter circuits for rail-bound vehicles face challenges in efficiently coupling to both DC and AC electric supply networks, leading to the need for heavy, space-consuming, and lossy filter circuits to remove double frequency power oscillations, which increase hardware costs and reduce reliability.
Innovation Solution
A traction converter circuit that uses a rectangular network converter control signal instead of a sinusoidal signal, eliminating the need for a filter circuit on the DC voltage side by reducing power oscillations to low frequency and amplitude, thereby simplifying the circuit and reducing weight, space, and hardware costs while increasing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a sinusoidal network converter control signal is used, then the network converter generates a voltage with a basic frequency, but a double frequency power oscillation of 200 Hz is obtained which must be filtered out, resulting in a heavy, space-consuming, and lossy filter circuit
Solution Approach 1:
The patent changes the control signal waveform from sinusoidal to rectangular, which fundamentally alters the frequency spectrum of the generated voltage. This parameter change eliminates the double frequency power oscillation at 200 Hz, thereby removing the need for a heavy filter circuit and resolving the contradiction between power quality and device complexity.
Solution Approach 2:
The patent extracts and removes the filter circuit from the system by changing the control signal type. By using a rectangular control signal, the harmful double frequency oscillation is eliminated at its source, allowing the filter circuit to be completely removed rather than just reduced, thus simplifying the overall device structure.
2Loss of energy
If a filter circuit is provided on the DC voltage side to filter out double frequency voltage components, then the power oscillation is removed, but the filter circuit is very heavy, requires a lot of space, is lossy, reduces reliability and significantly increases hardware costs
Solution Approach 1:
The patent applies preliminary action by eliminating the double frequency power oscillation at the source through the use of a rectangular control signal, before it can propagate to the DC voltage side. This preventive approach avoids the need for filter circuits and their associated reliability issues, while also reducing energy losses that would occur in the filter components.
Solution Approach 2:
The patent converts the potentially harmful double frequency oscillation into a beneficial simplification of the circuit design. By intentionally using a rectangular control signal that eliminates the oscillation problem, the design turns what could be a harmful effect into a benefit by removing the need for complex filtering, thereby improving reliability and reducing losses.
3Loss of energy
If a filter circuit is provided on the DC voltage side, then double frequency voltage components are filtered out, but weight, space and hardware costs are significantly increased
Solution Approach 1:
The patent changes the control signal parameter from sinusoidal to rectangular, which fundamentally alters the output voltage characteristics. This parameter change eliminates the double frequency voltage components that would require filtering, thereby removing the heavy filter circuit and its associated weight, while still achieving the goal of energy loss reduction.
4Loss of energy
If a filter circuit is provided on the DC voltage side, then power oscillation is reduced, but the traction converter circuit is simplified less and hardware costs are increased
Solution Approach 1:
The patent extracts and removes the filter circuit from the design by using a rectangular control signal that eliminates the need for filtering. This extraction simplifies the overall circuit structure, making it easier to manufacture, while still achieving the energy loss reduction goal by preventing power oscillation at its source.
Data Source
AI summary
A method for operating a traction converter circuit for coupling to an electric DC voltage network is stated, where the traction converter circuit comprises a network converter, which network converter on the DC voltage side is connected with a DC voltage circuit, wherein the DC voltage circuit can be switched to the electric DC voltage network, a transformer with a primary winding and a secondary winding, wherein the network converter on the alternating voltage side is connected with the primary winding of the transformer, a converter unit, which converter unit on the alternating voltage side is connected with the secondary winding of the transformer and where the network converter is controlled by means of a predeterminable network converter control signal (SN) for the setting of the network converter alternating voltage (UG). To simplify the traction converter circuit the network converter control signal (SN) according to the method is a rectangular signal which follows a reference rectangular signal (SClk).