Three-Level Bidirectional DC-AC Module for High-Power EV Charging
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Solution Overview
Problem
The existing charging systems for electric vehicles face inefficiencies, long charging times, high costs, and limited accessibility due to the need for dedicated charging stations and the inability to meet high power charging demands, especially with DC charging systems.
Innovation Solution
A charging system incorporating a three-level bidirectional DC-AC module that reduces common-mode voltage and leakage current, eliminates the need for a DC-DC converter, and enables high-power charging by communicating through modulated PWM signals, allowing for efficient charging using either single-phase or three-phase AC power without the requirement of a dedicated charging pile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If DC charging station is used, then charging power is high, but charging efficiency is low and charging time is long
Solution Approach 1:
The patent changes the voltage level parameter by using high-voltage AC charging (e.g., 380V or higher) instead of traditional low-voltage AC or DC charging. This parameter change enables the system to deliver high charging power while maintaining high charging efficiency, resolving the contradiction between high power and low efficiency in existing DC charging systems
2Power
If DC charging station is used, then charging power is high, but charging cost is high and covering area is large
Solution Approach 1:
The patent designs a charging system that can universally accept various AC power sources (single-phase, three-phase, high-voltage) and adapt to different charging power requirements. The charging device integrates multiple functions including voltage detection, power management, and communication, eliminating the need for separate DC charging stations and reducing the covering area required for high-power charging infrastructure
3Volume of moving object
If in-vehicle charger is used, then space requirement is small, but charging power is insufficient
Solution Approach 1:
The patent changes the voltage parameter from traditional low-voltage AC (220V) to high-voltage AC (380V or higher), enabling the in-vehicle charger to achieve high charging power while maintaining a compact design. The high-voltage AC charging module integrates advanced power electronics that deliver high power density, resolving the contradiction between small volume and sufficient charging power
4Power
If charging station is used, then charging power is sufficient, but number of stations is limited and accessibility is poor
Solution Approach 1:
The patent enables the electric vehicle itself to serve as the charging station by integrating a high-voltage AC charging module directly in the vehicle. The vehicle can autonomously detect available AC power sources (such as household outlets, industrial power supplies) and perform charging without requiring external charging stations, dramatically improving accessibility while maintaining high charging power
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 enhances charging efficiency, reduces costs, and shortens charging time, making it convenient to fast-charge electric vehicles anywhere, thereby facilitating the popularization of electric vehicles.
Implementation Method 1
the energy control device and the external power supply device communicate by transmitting a modulated PWM signal to each other
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
A charging system for an electric vehicle and a method for controlling charging of an electric vehicle are provided. The charging system comprises: a power battery (10); a charge-discharge socket (20); an external power supply device (1002); a charging connection device (1001); and an energy control device (1003), comprising: a three-level bidirectional DC-AC module (30); a charge-discharge control module (50); and a control module (60) configured to control the charge-discharge control module (50) according to a current working mode of the electric vehicle. The energy control device (1003) and the external power supply device (1002) communicate by transmitting a modulated PWM signal to each other via the charging connection device (1001), and the control module (60) controls the three-level bidirectional DC-AC module (30) and the charge-discharge control module (50) to charge the power battery (10) by the external power supply device (1002).