Vehicle Electrical Architecture Using Motor Windings as DC/DC Inductors
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Solution Overview
Problem
Current vehicle electrical systems face challenges in achieving improved compactness, weight efficiency, and cost-effectiveness, particularly in plug-in electrical vehicles, due to the need for large and costly inductors and switches in the powertrain for DC/DC converters.
Innovation Solution
The vehicle electrical system positions the DC/DC converter outside the powertrain, utilizing the windings of electric machines as buck/boost inductances and employing less powerful electronic switches, and features a bidirectional AC/DC and DC/DC converter design that allows for versatile operation modes, including single-phase or three-phase charging and vehicle-to-grid power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a DC/DC converter is positioned inside the powertrain, then the system can provide integrated power management, but the system weight and cost increase due to requiring large inductors and high-power switches
Solution Approach 1:
The patent extracts the DC/DC converter from the powertrain and positions it outside, eliminating the need for large inductors and high-power switches within the powertrain. This separation allows the use of smaller, less expensive components while maintaining power management functionality through the electrical machines' windings.
Solution Approach 2:
The patent makes the electrical machines' windings serve dual functions: as motor/generator windings for propulsion and as inductors for the DC/DC converter operation. This multi-functionality eliminates the need for separate inductor components, reducing weight and cost.
2Power
If high-power switches with 200-400 Ampere capacity are used in the powertrain DC/DC converter, then the converter can handle powertrain power levels, but the cost and complexity increase significantly
Solution Approach 1:
By moving the DC/DC converter outside the powertrain, the system can use lower-power switches with 30 Ampere capacity instead of expensive 200-400 Ampere switches, significantly reducing cost while maintaining adequate power handling through the external converter configuration.
Solution Approach 2:
The electrical machines' windings provide the inductance function that would otherwise require separate, expensive inductor components. The system uses its own existing components (the motor windings) to perform the inductor function, eliminating additional cost and complexity.
3Adaptability or versatility
If separate buck/boost inductors are included in the DC/DC converter, then the converter can perform voltage step-up/step-down operations, but the weight and cost increase
Solution Approach 1:
The patent makes the electrical machines' windings serve dual functions: as motor/generator windings for propulsion and as inductors for the DC/DC converter operation. This multi-functionality eliminates the need for separate inductor components, reducing weight and cost while maintaining voltage conversion capability.
Solution Approach 2:
The patent merges the function of the electrical machine windings with the inductor function of the DC/DC converter. By combining these functions into a single component set, the system eliminates separate inductor components, thereby reducing overall weight and cost.
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 configuration reduces weight and cost by eliminating separate inductors, enables efficient voltage step-up/down, and provides high versatility in input and storage voltage levels, while allowing for cost-effective and efficient operation.
Implementation Method 1
a bidirectional buck-boost DC/DC converter (19) operatively connected to the common neutral point (29) of the first multiphase electrical machine (5a) and to the common neutral point (29) of the second multiphase electrical machine (5b) and configured for using at least one stator winding (8, 13) of each of the first and second multiphase electrical machines (5a, 5b) as buck-boost inductance
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
A vehicle electrical system comprising an electrical storage system (6), a first multiphase electrical machine (5a) having a plurality of stator windings (8) connected to common neutral point, a first inverter (9a) operatively connected to the electrical storage system (6) and to the first multiphase electrical machine (5a), wherein the first inverter (9a) has a plurality of switch legs (10, 11, 12) with switches (10a, 10b, 11a, 11b, 12a, 12b), a second multiphase electrical machine (5b) having a plurality of stator windings (13) connected to a common neutral point, a second inverter (9b) operatively connected to the electrical storage system (6) and to the second multiphase electrical machine (5b), wherein the second inverter (9b) has a plurality of switch legs (14, 15, 16) with switches (14a, 14b), a bidirectional buck-boost DC/DC converter operatively connected to the common neutral point of the first multiphase electrical machine (5a) and to the common neutral point of the second multiphase electrical machine (5b) and configured for using at least one stator winding of each of the first and second multiphase electrical machines (5a, 5b) as buck-boost inductance, a bidirectional AC/DC converter operatively connected to the DC/DC converter and to a charging terminal (7) with or without an intermediate electrical filter arrangement, and an electronic control system (21) for controlling operation of the vehicle electrical system.