EV Power Supply Using Transformer Isolation Instead of DC/DC
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Solution Overview
Problem
Conventional electrical power supply systems for electric vehicles suffer from energy inefficiencies due to the use of non-isolated, costly switched-mode DC/DC converters, and they lack adequate safety measures to prevent contact between high-voltage and low-voltage sides.
Innovation Solution
The proposed electrical power supply system employs a multi-phase electrical transformer and a rectifier circuit to convert high-voltage AC power into low-voltage DC power, eliminating the need for a traditional DC/DC converter. This design enhances energy efficiency, reduces costs, and ensures galvanic isolation for improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a non-isolated switched-mode DC/DC converter is used to transfer power from high-voltage side to low-voltage side, then power transfer is enabled, but energy losses are significant and safety isolation is compromised
Solution Approach 1:
The patent introduces an AC coupling stage as an intermediary between the high-voltage and low-voltage sides. The DC/AC converter converts DC to AC, which then passes through a transformer providing galvanic isolation, and finally a rectifier converts AC back to DC. This intermediary AC stage enables both efficient power transfer and safety isolation, resolving the contradiction between energy efficiency and safety.
Solution Approach 2:
The patent replaces the direct electrical connection (mechanical/electrical coupling) of traditional DC/DC converters with an electromagnetic field-based transformation system. By using AC conversion and transformation through a transformer, the system achieves galvanic isolation while maintaining efficient power transfer, substituting direct electrical contact with electromagnetic coupling.
2Ease of manufacture
If a traditional DC/DC converter is used, then power conversion is achieved, but the system becomes costly and complex
Solution Approach 1:
The patent makes the inverter serve multiple functions: it acts as both the traditional DC/AC inverter for the motor and as a DC/AC converter for the new power supply path to the low-voltage battery. This multi-functionality reduces the need for separate dedicated converters, simplifying the overall system and reducing costs while maintaining power conversion capabilities.
Solution Approach 2:
The patent merges the existing inverter functionality with the new DC/AC conversion function for the low-voltage power supply. By combining these functions into a single inverter unit, the system reduces component count, simplifies manufacturing, and lowers overall system complexity while achieving the desired power conversion and isolation.
3Reliability
If a multi-phase electrical transformer and rectifier circuit are used instead of a DC/DC converter, then galvanic isolation and efficiency are improved, but additional components are introduced
Solution Approach 1:
The patent makes the inverter serve multiple functions: it acts as both the traditional DC/AC inverter for the motor and as a DC/AC converter for the new power supply path to the low-voltage battery. This multi-functionality reduces the need for separate dedicated converters, simplifying the overall system and reducing costs while maintaining power conversion capabilities.
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 higher efficiency, lower costs, and reduced complexity compared to traditional systems, while ensuring high power supply safety and compliance with ASIL risk classification. It also provides a more compact and reliable design with reduced weight and voltage drops.
Implementation Method 1
a first multi-phase electrical transformer having a primary side and a secondary side, wherein the primary side is operatively connected to the output of the first inverter and configured to receive multi-phase high-voltage AC electrical power, and wherein the secondary side is configured to output multi-phase low-voltage AC electrical power
Implementation Method 2
a first rectifier circuit operatively connected to the secondary side of the first multi-phase electrical transformer and configured to output low-voltage DC electrical power
Data Source
Figure 1~2
Figure 3~5
Figure 6~7B
AI summary
An electrical power supply system (6) for an electric vehicle comprising a first high-voltage battery (5) connected to a first inverter (7), which is connected to a first electric motor (4) of the vehicle. The first inverter is also connected to a primary side of a first multi-phase electrical transformer (14), and a secondary side (16) is connected to a first rectifier circuit (17) for outputting low-voltage DC electrical power. A first low-voltage battery (8) is connected to the first rectifier circuit (17) for charging of the first low-voltage battery (8), and the first rectifier circuit (17) and/or the first low-voltage battery (8) are configured to supply low-voltage DC electrical power to at least a first electrical load (L1, L2) of the vehicle.