Common Minus-Pole EV Charging Using Motor-Inverter Voltage Boost

Solution Overview

Problem

Existing electric vehicles with 800 volt battery systems require onboard DC-DC voltage booster converters to charge at 500 volt charging stations, consuming space and increasing costs.

Innovation Solution

A charging system that utilizes a three-phase electric motor, inverter, and booster charging cable to bypass connections, allowing direct charging from 500 volt stations to 800 volt batteries, reducing the need for additional converters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a DC-DC voltage booster converter is installed in an 800 volt electric vehicle to charge at 500 volt charging stations, then the vehicle can be charged at existing charging infrastructure, but the converter consumes considerable space inside the vehicle and increases vehicle cost

Engineering Contradiction:

Improvecharging compatibilityVSAvoidconverter space

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The inverter is designed to perform multiple functions: it serves as both the motor controller during vehicle operation and as the DC-DC voltage booster converter during charging operations. By integrating the boosting capability into the existing inverter, the system eliminates the need for a separate converter device, thereby reducing space consumption while maintaining charging compatibility with 500 volt stations for 800 volt vehicles

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the functions of the inverter and the DC-DC booster converter into a single integrated unit. The inverter's switching devices and control circuitry are utilized for both motor control and voltage boosting operations, merging two previously separate systems into one unified component that reduces overall system complexity and space requirements

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If a DC-DC voltage booster converter is installed in an 800 volt electric vehicle to charge at 500 volt charging stations, then the vehicle can be charged at existing charging infrastructure, but the converter adds to the cost of the electric vehicle

Engineering Contradiction:

Improvecharging compatibilityVSAvoidvehicle cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The inverter is designed to perform multiple functions: it serves as both the motor controller during vehicle operation and as the DC-DC voltage booster converter during charging operations. By integrating the boosting capability into the existing inverter, the system eliminates the need for a separate converter device, thereby reducing space consumption while maintaining charging compatibility with 500 volt stations for 800 volt vehicles

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the functions of the inverter and the DC-DC booster converter into a single integrated unit. The inverter's switching devices and control circuitry are utilized for both motor control and voltage boosting operations, merging two previously separate systems into one unified component that reduces overall system complexity and space requirements

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12401215B2Voltage conversion system for battery electric powertrain with common minus-pole

Publication Date: 2025.08.26 VOLVO CAR CORP

AI summary

An electric vehicle charging system is provided. In some embodiments, the electric vehicle charging system can comprise an electric motor drive system comprising a three-phase electric motor and an inverter. In various embodiments, a negative cable can be connected to an electric vehicle inlet and a battery. In further embodiments, a booster charging cable can be connected to a star-point of the three-phase electric motor and to a positive pole of the electric vehicle inlet, wherein the booster charging cable bypasses a connection between the positive pole and the battery.