Multiphase Electrical Machine Transfer Circuit for Dual-Voltage Power Management
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Solution Overview
Problem
Existing vehicle onboard electrical systems with dual voltage sub-systems require multiple components, including a DC chopper and energy stores, to manage power transfer between sub-systems, which is inefficient and complex.
Innovation Solution
A multiphase electrical machine with a star or delta configured stator system and a transfer circuit using counter-switched diodes and switches to connect the star point of one stator system to the higher potential of another sub-system, allowing for direct electrical coupling and independent operation as a generator or motor across both sub-systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DC chopper circuit is used to transfer electrical power between two onboard electrical sub-systems, then power transfer capability is achieved, but device complexity increases due to requiring multiple components including energy stores and chopper circuits
Solution Approach 1:
The patent combines the functions of the electrical machine, inverter, and transfer circuit into an integrated system. The electrical machine serves dual purposes as both motor and generator while the transfer circuit integrates the coupling between star points of different stator systems, eliminating the need for separate DC chopper circuits and energy stores.
Solution Approach 2:
The electrical machine is designed to operate in multiple modes: as a motor driven by the first onboard electrical sub-system, as a generator driving the second onboard electrical sub-system, and as a transfer circuit enabling power transfer between sub-systems. This multi-functionality replaces multiple specialized components.
2Adaptability or versatility
If multiple energy stores and DC chopper circuits are used for power transfer, then power management capability is achieved, but conduction losses increase
Solution Approach 1:
By merging the power management functions into the electrical machine and transfer circuit, the patent eliminates multiple intermediate conversion stages. The direct coupling through the transfer circuit reduces conduction losses compared to multiple separate energy stores and chopper circuits.
3Productivity
If a transfer circuit connects the star point of the first stator system to the higher potential of the second onboard electrical sub-system, then direct electrical coupling is achieved, but system configuration complexity increases
Solution Approach 1:
The transfer circuit acts as an intermediary element that directly couples the star point of the first stator system to the higher potential of the second onboard electrical sub-system. This intermediary enables efficient power transfer while the control unit manages the complexity of switching operations.
Solution Approach 2:
The system dynamically changes operational parameters including switching states of the first and second switches, and the configuration of the electrical machine between motor and generator modes, to optimize power transfer efficiency under different operating conditions.
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 simplifies power transfer between onboard electrical sub-systems, reduces conduction losses, and enables efficient operation as a DC step-up or step-down converter without the need for a DC chopper, enhancing energy management and system flexibility.
Implementation Method 1
A transfer circuit electrically connects the star point of the first stator system to the higher potential of the second onboard electrical sub-system
Implementation Method 2
enables efficient operation as a DC step-up or step-down converter
Data Source
AI summary
A vehicle is provided with a multiphase electrical machine, a first onboard electrical sub-system having a first nominal DC voltage, and a second onboard electrical sub-system having a second nominal DC voltage. The electrical machine includes a rotor, a first stator system and a second stator system. The first onboard electrical sub-system includes a first inverter with a first link capacitor. The first stator system is associated with the first inverter. The second onboard electrical sub-system includes a second inverter with a second link capacitor. The second stator system is associated with the second inverter. The first stator system is configured in a star configuration. The second stator system is configured in a star configuration or in a delta configuration. A transfer circuit connects the star point of the first stator system to a higher potential of the second onboard electrical sub-system.