Traction Network Topology for 400V/800V Charging Adaptation
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Solution Overview
Problem
Existing traction networks face challenges with dielectric strength issues in semiconductor switches due to high operating voltages, inconsistent charging infrastructure, and inefficiencies in charging power utilization.
Innovation Solution
A traction network design that includes a high-voltage battery, an inverter, an electric machine, a rectifier, and a bidirectional DC/DC converter, which allows for optimized operating point adjustment of the electric machine and flexible charging voltage adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high operating voltages (e.g., 800 V) are used in the traction network to reduce currents, then the current reduction is achieved, but the dielectric strength of semiconductor switches becomes insufficient
Solution Approach 1:
The patent divides the high-voltage battery into multiple battery units (e.g., two 400V units) that can be connected in series to achieve 800V operation. This segmentation allows the system to operate at high voltage for reduced current while using semiconductor switches rated for lower voltage (400V), thus resolving the dielectric strength issue.
2Reliability
If the traction network uses a fixed topology for 800 V operation, then the dielectric strength issue is addressed, but the maximum charging power cannot be fully exploited and the circuitry becomes costly
Solution Approach 1:
The patent implements a dynamic switching mechanism that can reconfigure the battery units between series (800V) and parallel (400V) connections based on charging requirements. This dynamic topology adaptation allows the system to fully exploit both 400V and 800V charging infrastructure while maintaining cost-effective semiconductor switch selection.
3Adaptability or versatility
If a rectifier and DC/DC converter are added to enable AC charging, then AC charging capability is achieved, but the device complexity increases
Solution Approach 1:
The patent designs the DC/DC converter with bidirectional capability to perform multiple functions: it converts rectified voltage to battery voltage for AC charging, and also enables voltage adaptation between 400V and 800V configurations. This multi-functionality reduces the need for separate dedicated components for each function.
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 proposed solution enhances the flexibility and efficiency of the traction network by optimizing the electric machine's operating points and adapting to various charging voltages, while reducing component count and costs.
Implementation Method 1
A bidirectional DC/DC converter is arranged between the high-voltage battery and the inverter. The DC/DC converter is designed to match the inverter in terms of power, such that the inverter is sufficiently dimensioned for AC charging.
Implementation Method 2
In this case, a rectifier which converts the AC voltage into a DC voltage is arranged between the AC charging terminal and the high-voltage battery.
Data Source
AI summary
The disclosure relates to a traction network for a motor vehicle, wherein the traction network comprises at least one high-voltage battery, an inverter, an electric machine, a DC charging terminal, and an AC charging terminal, wherein a rectifier and a DC/DC converter are arranged between the AC charging terminal and the high-voltage battery, wherein a DC/DC converter is arranged between the high-voltage battery and the inverter.