Three-Stage Converter for Hybrid Vehicle Battery Charging
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Solution Overview
Problem
Existing circuit arrangements for hybrid or electric vehicles face inefficiencies in charging high-voltage batteries, particularly when the charging infrastructure provides voltages lower than the battery's voltage, requiring additional converters or specialized charging columns, which increase costs and complexity.
Innovation Solution
A three-stage converter is designed with switch units connected to each phase of a multi-phase electric machine, allowing for sequential charging of battery segments via a charging connection, enabling charging with both 400V and 800V DC infrastructure without the need for additional converters or specialized charging columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional single-stage converter is used for charging, then the charging system is simple, but it cannot charge high-voltage batteries when the charging infrastructure provides lower voltages
Solution Approach 1:
The battery is divided into multiple battery segments (first battery segment and second battery segment) that can be independently connected to the charging connection. The converter is segmented into multiple switch groups (first switch group, second switch group) that can independently control charging of each battery segment, enabling flexible adaptation to different charging voltages.
Solution Approach 2:
The converter dynamically switches between different switching states (first switching state, second switching state, third switching state) to adapt to different charging scenarios. The switch groups can be selectively activated or deactivated based on the charging voltage available, allowing the system to optimize its configuration in real-time.
2Adaptability or versatility
If additional converters or specialized charging columns are used to enable charging with lower voltages, then charging compatibility is improved, but costs and system complexity increase
Solution Approach 1:
The converter is designed with multi-functionality to perform both charging operations and AC voltage conversion for the electric machine. By making the converter universal, the system eliminates the need for separate dedicated charging converters or specialized charging columns, thereby reducing overall system cost while maintaining compatibility with both 400V and 800V charging infrastructures.
Solution Approach 2:
The converter uses its own internal switch groups and switching states to adapt to different charging voltages without requiring external specialized equipment. The system serves itself by internally reconfiguring its circuit topology to match the available charging infrastructure, eliminating the need for additional external converters or specialized charging columns.
3Adaptability or versatility
If the converter is designed as a three-stage converter with multiple switch groups, then charging flexibility is improved, but the converter complexity increases
Solution Approach 1:
The charging functions and AC voltage conversion functions are merged into a single three-stage converter. The same switch groups and circuit topology used for charging are also used for converting DC voltage to AC voltage for the electric machine, thereby reducing overall system complexity despite the increased flexibility of the charging capability.
Solution Approach 2:
The three-stage converter is designed as a universal component that performs multiple functions: charging the battery from DC voltage sources of different voltages, and converting DC voltage to AC voltage for the electric machine. This multi-functionality justifies the increased converter complexity by eliminating the need for separate dedicated systems.
4Adaptability or versatility
If sequential charging of battery segments is implemented, then compatibility with 400V infrastructure is improved, but charging time may increase
Solution Approach 1:
The converter dynamically switches between different switching states to optimize charging time. When charging from a 400V source, the system can sequentially charge battery segments, but when an 800V source is available, the system switches to a configuration that charges both segments simultaneously, thereby minimizing charging time based on the available infrastructure.
Solution Approach 2:
The system changes its operational parameters (switching states, circuit topology) based on the available charging voltage. By detecting the charging voltage level, the system adjusts its charging strategy - using sequential charging for 400V compatibility or parallel charging for 800V optimization - thereby adapting charging duration to match the infrastructure available.
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 allows for efficient charging of high-voltage batteries across various charging infrastructures, reducing costs and complexity by utilizing a dual-function converter that can also supply high-voltage AC voltage to the electric machine, thereby optimizing battery charging and vehicle components.
Implementation Method 1
The respective switch group has two IGBTs connected in series to each other. As is already sufficiently known from the general prior art, the IGBT is an insulated-gate bipolar transistor having an insulated gate electrode.
Implementation Method 2
a converter is provided, by means of which high-voltage DC voltage, which can be or is provided by the high-voltage battery, can be converted into high-voltage AC voltage for operating the electric machine
Data Source
AI summary
A circuit arrangement of a motor vehicle includes a high-voltage battery for storing electrical energy, an electric machine for driving the motor vehicle, a converter via which high-voltage direct current voltage provided by the high-voltage battery is convertible into high-voltage alternating current voltage for operating the electric machine, and a charging connection for providing electrical energy for charging the high-voltage battery. The converter is a three-stage converter having a first switch unit which is assigned to a first phase of the electric machine. The first switch unit has two switch groups connected in series which each have two insulated-gate bipolar transistors (IGBTs) connected in series, where a connection is disposed between the IGBTs of one of the two switch groups, which connection is electrically connected directly to a line of the charging connection.