Multi-Winding Converter Topology for Cascaded Module Power Balance
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Solution Overview
Problem
Conventional DC charging systems for electric vehicles suffer from self-loss, large volume, and power imbalance issues due to the need for multiple transformers and isolated DC/DC converters, leading to excessive bus voltage and potential system damage.
Innovation Solution
A cascaded multi-port converter system with multi-winding transformers and low-voltage rectifying units, where secondary windings are connected through a bus to ensure power balance and reduce the number of low-voltage rectifying units, using bidirectional switches and redundant modules to manage power exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple power-frequency transformers and isolated DC/DC converters are arranged in conventional DC charging piles to ensure safety isolation, then safety isolation between input and output is improved, but device volume and self-loss increase significantly
Solution Approach 1:
The patent combines the power-frequency transformer and isolated DC/DC converter functions into a single integrated transformer with multiple windings. The primary winding connects to the power-frequency transformer input, while multiple secondary windings provide isolated outputs to multiple charging modules, eliminating the need for separate isolated DC/DC converters in each module and reducing overall device volume.
Solution Approach 2:
The integrated transformer serves multiple functions simultaneously: it provides power-frequency transformation, voltage conversion, and isolated power supply to multiple charging modules. The multi-winding structure allows a single transformer to replace multiple separate transformers and converters, reducing both volume and self-loss while maintaining safety isolation.
2Reliability
If multiple power-frequency transformers and isolated DC/DC converters are arranged in conventional DC charging piles to ensure safety isolation, then safety isolation between input and output is improved, but energy loss increases due to multiple conversion stages
Solution Approach 1:
The patent combines the power-frequency transformer and isolated DC/DC converter functions into a single integrated transformer with multiple windings. The primary winding connects to the power-frequency transformer input, while multiple secondary windings provide isolated outputs to multiple charging modules, eliminating the need for separate isolated DC/DC converters in each module and reducing overall device volume.
Solution Approach 2:
The integrated transformer enables continuous power transmission from the input to multiple output modules in a single transformation stage. By eliminating intermediate conversion stages and separate isolated DC/DC converters, the system maintains continuous useful action with reduced energy loss at each conversion interface.
3Productivity
If cascaded modules are connected in parallel to a DC bus without power balance control, then charging capacity is improved, but bus voltage becomes excessive causing system damage
Solution Approach 1:
The patent implements power balance control for cascaded modules connected to the DC bus. Each module's output power is monitored and regulated to maintain balance, preventing excessive bus voltage that could damage the system. This feedback mechanism allows multiple modules to operate in parallel at full capacity while maintaining system security through active power management.
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
The system achieves power balance between cascaded modules, reducing self-loss, volume, and cost while enhancing system security by minimizing excessive bus voltage and simplifying energy management.
Implementation Method 1
Each of the multiple module units includes at least one multi-winding transformer... a primary winding of a multi-winding transformer is connected to an output end of a corresponding high-voltage conversion unit; and a secondary winding of the multi-winding transformer is connected to an input end of a corresponding low-voltage rectifying unit
Data Source
AI summary
A cascaded multi-port converter and a three-phase medium-voltage input system. Input ends of all high-voltage conversion units are cascaded between two ports of an input end of the cascaded multi-port converter. A primary winding of a multi-winding transformer is connected to an output end of a corresponding high-voltage conversion unit, and a secondary winding of the multi-winding transformer is connected to an input end of a corresponding low-voltage rectifier unit. Output ends of some of the low-voltage rectifier units are connected to each other through a bus, and the remaining low-voltage rectifier units outputs independently, such that at least one secondary winding in each multi-winding transformer is indirectly connected to the bus, and at least one multi-winding transformer is provided with at least one secondary winding that independently outputs. Therefore, power balance between various modular units is achieved, and the security of the cascaded multi-port converter is improved.