Three-Port DC/DC Converter Topology for Power Flow Control
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Solution Overview
Problem
Existing power conversion systems in electric and hybrid vehicles require multiple DC/DC converters for omnidirectional power flow between DC-isolated voltage systems, leading to inefficiencies, increased costs, and low power density due to duplicate circuit components and high voltage transformation ratios.
Innovation Solution
A multi-port multi-cell converter topology with interconnected three-port converter cells, utilizing transformer coils in series and parallel configurations to manage power flow between AC, HV, and LV systems, allowing for efficient power distribution and reduced switching losses through phase-shifted operation of full-bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two independent DC-isolated DC/DC converters are used to control power flow between three DC voltage systems, then power flow control between the systems is achieved, but device complexity increases and power density decreases due to duplicate circuit components
Solution Approach 1:
The patent combines two independent DC/DC converters into a single three-port converter that can handle power flow between three DC voltage systems (HV system, LV system, and AC system). This merging eliminates duplicate circuit components such as transformers and electronic changeover switches, reducing device complexity while maintaining the ability to control power flow in multiple directions between all systems.
Solution Approach 2:
The three-port converter is designed with universal functionality to manage power flow between any combination of the three DC voltage systems. It can operate in multiple modes: charging/discharging the HV battery, charging/discharging the LV battery, and interfacing with the AC system, thereby replacing multiple specialized converters with a single multi-functional device.
2Reliability
If two independent DC/DC converters are used for power flow management, then system reliability is maintained through redundancy, but production costs increase due to duplicate components
Solution Approach 1:
By merging the functionality of two independent converters into one three-port converter, the patent reduces the total number of critical components (transformers, power semiconductors, control circuits) that need to be manufactured and assembled. This consolidation directly lowers production costs while the integrated design maintains system reliability through coordinated control of power flow between all three voltage systems.
3Object-affected harmful factors
If conventional DC/DC converters with high voltage transformation ratios are used, then DC isolation for safety is achieved, but efficiency decreases and switching losses increase
Solution Approach 1:
The three-port converter segments the voltage transformation function across three separate ports, each handling a specific voltage system (HV, LV, AC). This segmentation allows each port to operate at optimized voltage levels and switching frequencies, reducing the overall voltage transformation ratio requirements and minimizing switching losses while maintaining DC isolation for safety between all systems.
Solution Approach 2:
The converter employs parameter changes by operating each port at different voltage levels and switching frequencies optimized for its specific function. This allows the system to achieve the required voltage conversion with lower transformation ratios at each stage, reducing switching losses and improving efficiency while maintaining the necessary DC isolation for safety.
4Adaptability or versatility
If duplicate circuit components are installed in two independent converters, then power flow control flexibility is improved, but power density decreases due to low system integration
Solution Approach 1:
The patent merges all power flow control functionality into a single integrated three-port converter, eliminating the need for duplicate circuit components across two separate converters. This high-level integration achieves superior power density by consolidating all power electronic components, magnetic elements, and control circuits into one compact unit while maintaining the flexibility to control power flow in any direction between all three voltage systems.
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 approach enhances power density, reduces component volume, and improves efficiency by distributing power symmetrically across cells, using transistors with lower blocking voltages and allowing higher switching frequencies, while maintaining stable operation across varying voltage levels.
Implementation Method 1
at least two converter cells with a transformer having at least three transformer coils
Data Source
AI summary
A converter for controlling power flows between three electricity networks with different operating voltages. The converter includes, in one implementation, three terminals and two converter cells. Each of the three terminals are configured to electrically contact-connect one of the three electricity networks. Each of the two converter cells includes a transformer having three converter cells. One of the terminals is connected to a series circuit of the converter cells. Another of the terminals is connected to a parallel circuit of the converter cells.