Power Converter Circuit with Transformer Synchronization
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Solution Overview
Problem
There is a need for a power converter circuit that efficiently transforms relatively low DC supply voltages from photovoltaic modules into AC supply voltages compatible with power grid voltages, addressing inefficiencies in existing conversion methods due to large voltage differences and the requirement for synchronized control in multi-level switching patterns.
Innovation Solution
A power converter circuit with a synchronization circuit generating signals that control a series of converter units, each including a transformer, to synchronize the frequency and phase of the output current with the AC voltage of the power grid, allowing for efficient conversion without the need for constant synchronized control of individual units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If several DC/AC converters are connected in series with constant synchronized control, then the AC voltage output is consistent with power grid standards, but the control complexity increases significantly
Solution Approach 1:
The converter units automatically synchronize their output based on the series connection topology and load conditions, eliminating the need for external constant synchronized control. Each unit self-adjusts its operation to maintain AC voltage consistency with power grid standards through the inherent properties of the series configuration and load interaction.
2Adaptability or versatility
If multiple DC/AC converters are used with low DC voltage input, then the system can handle lower voltage PV modules, but the conversion efficiency decreases due to large voltage difference
Solution Approach 1:
The system divides the voltage conversion task across multiple converter units connected in series. Each unit handles a portion of the total voltage transformation, reducing the voltage difference each individual converter must bridge. This segmentation maintains adaptability to low voltage PV modules while improving overall conversion efficiency by avoiding excessive voltage ratios in single-stage conversion.
3Loss of energy
If high DC voltage is used to match power grid AC voltage peak, then conversion efficiency improves, but electric arc hazards increase
Solution Approach 1:
The high voltage requirement is segmented across multiple series-connected converter units, each operating at lower voltage levels. This distribution maintains the necessary voltage transformation efficiency while reducing the electric arc hazard in each individual unit, as the voltage stress and associated arc risk are divided among several components rather than concentrated in a single high-voltage converter.
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
This solution enables efficient conversion of low DC voltages to AC voltages matching power grid standards, improving efficiency and reducing the complexity of synchronized control, thereby stabilizing the AC voltage and optimizing energy transfer.
Implementation Method 1
at least one of the plurality of converter units comprises a transformer and is configured to generate an output current such that at least one of a frequency and a phase of the generated output current is dependent on the synchronization signal
Data Source
AI summary
A power converter circuit includes a synchronization circuit that is configured to generate at least one synchronization signal. A series circuit includes a number of converter units configured to output an output current. At least one of the converter units includes a transformer and is configured to generate an output current such that a frequency or a phase of the generated output current is dependent on the synchronization signal.