Multi-source Power Converter with Bidirectional Switches
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Solution Overview
Problem
Existing power converters are inefficient due to a high number of switches and components, leading to increased power loss, heat dissipation, and production costs, and require multi-stage conversion processes, which are not suitable for modern energy storage and renewable energy systems.
Innovation Solution
A power converter design utilizing a plurality of DC terminals and converter cells with bidirectional switches, capable of converting power between multiple independent DC voltage sources and AC loads in a single stage, reducing the number of switches and enabling efficient multi-level power output with fault-tolerant operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing switching devices use a relatively high number of switches and components, then they can achieve power conversion functionality, but they result in increased power loss, heat dissipation, and production costs
Solution Approach 1:
The power converter is divided into multiple converter cells, each handling a portion of the power conversion task. This segmentation allows the system to achieve the required power conversion functionality with fewer switches per cell, reducing overall power loss while maintaining the necessary complexity distribution
Solution Approach 2:
Multiple converter cells are combined in parallel to achieve the desired power conversion capacity. This merging approach allows the system to share the switching burden across multiple cells, reducing the number of switches needed in each individual cell and thereby reducing power loss and heat dissipation
2Productivity
If existing power converters use a multistage conversion process, then they can convert DC power to AC power, but they require more components and are less efficient
Solution Approach 1:
The invention extracts and eliminates the intermediate DC-DC conversion stage from the traditional multi-stage conversion process. By using converter cells that can directly convert DC to AC through bidirectional switches, the system reduces the number of conversion stages while improving overall efficiency
Solution Approach 2:
The converter cells are designed with bidirectional switches that can operate in multiple modes, enabling both DC-DC conversion and DC-AC conversion within the same cell. This multi-functionality eliminates the need for separate conversion stages and components, improving productivity while reducing device complexity
3Ease of manufacture
If isolating transformers and multistage conversion processes are used, then power conversion can be achieved, but production costs increase
Solution Approach 1:
The invention removes isolating transformers from the power converter design. By using galvanically isolated bidirectional switches within the converter cells, the system achieves the necessary isolation functionality without requiring separate transformer components, thereby reducing production costs while maintaining ease of manufacture
Solution Approach 2:
The invention changes the operating parameters of the power converter by using high-frequency switching with bidirectional switches. This parameter change allows the system to achieve power conversion and isolation without traditional transformers, reducing component count and production costs while maintaining manufacturing simplicity
Data Source
AI summary
A multi-source power converter is proposed to permit bidirectional DC to AC conversion from n (n≧2 and nε) DC voltage sources to an AC load with a reduced number of switches, and DC to DC conversion. Both single and three phases AC load are considered. The proposed topology consists in a single stage of conversion, and therefore a high efficiency can be expected for the system. Any type of DC sources can be used in the system (fuel-cell, battery, ultra-capacitor, photo-voltaic cells, DC bus, DC to DC or AC to DC converter, etc.). The AC load can be either single or three phases (single-phase AC grid/microgrid, three-phase electric machines, induction machine, synchronous machine, etc.). There is no requirement for the n DC voltage source values; they can be equal or different and they can be used individually or together by the converter to generate the AC output. If different DC voltage values are used, the converter can be controlled to generate a multi-level AC voltage. This permits to improve system's voltage and current power quality and to reduce electro-magnetic interferences (EMI). Therefore gains on both differential and EMI filters design can be expected.