Multi-Stator Vehicle Electrical Machine with Transfer Circuit
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Solution Overview
Problem
Existing vehicle electrical systems with multiple voltage levels require complex configurations and additional components to manage power transfer between different on-board networks, limiting efficiency and flexibility in operation.
Innovation Solution
A vehicle electrical system with a multi-phase electrical machine featuring two stator systems in star connection, connected via a transfer circuit with diodes and switches, allowing direct electrical coupling and pulse-width-modulated control for bidirectional power transfer between on-board networks, enabling operation as a motor or generator in both networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DC converter is used to transfer power between two on-board networks with different voltage levels, then power transfer between voltage levels is enabled, but device complexity increases
Solution Approach 1:
The patent combines the functions of the electrical machine and the DC converter into a single integrated system. The electrical machine with two stator systems directly enables bidirectional power transfer between the two on-board networks without requiring a separate DC converter, thus reducing device complexity while maintaining power transfer capability
Solution Approach 2:
The electrical machine serves multiple functions: it acts as a motor for drive functions, as a generator for energy recovery, and as a DC converter for power transfer between different voltage levels. This multi-functionality eliminates the need for separate dedicated components for each function
2Power
If traditional electrical machine configuration is used in multi-voltage systems, then basic motor/generator functions are provided, but conduction losses increase
Solution Approach 1:
The transfer circuit acts as an intermediary between the two stator systems, providing a direct low-impedance connection path. This intermediary structure enables efficient power transfer with reduced conduction losses compared to traditional configurations that would require power conversion through intermediate stages
3Loss of energy
If direct coupling of stator systems is implemented, then power transfer efficiency is improved, but control complexity increases
Solution Approach 1:
The system employs dynamic switching control where the switches in the transfer circuit are controlled based on the operating mode (motor, generator, or DC converter mode). This dynamic control approach enables the system to adapt to different operating conditions while maintaining simple control logic for each specific mode
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 on-board networks without the need for a DC converter, enhances start-up behavior, and reduces conduction losses, offering adjustable energy transfer directions and improved efficiency in buck and boost operations.
Implementation Method 1
the transfer circuit comprises a first diode and a second diode connected in opposition and in series
Implementation Method 2
the electric machine, which can also be operated as a motor in a vehicle with an electrified drive train
Implementation Method 3
the three high-side switches of the first inverter and the three low-side switches of the first inverter can be controlled with pulse width modulation
Data Source
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AI summary
The invention relates to a vehicle having a multi-phase electrical machine, comprising a first partial on-board network (BN1') having a first nominal DC voltage and a second partial on-board network (BN2') having a second nominal DC voltage. According to the invention, the electrical machine has a rotor (7), a first stator system (5) and a second stator system (6), the first partial on-board network (BN1') comprising a first inverter (13) having a first intermediate circuit capacitor (11), wherein the first stator system (5) is associated with the first inverter (13), and the second partial on-board network (BN2') comprising a second inverter (14) having a second intermediate circuit capacitor (12), wherein the second stator system (6) is associated with the second inverter (14). The first stator system (5) is designed in a star connection and the second stator system (6) is designed in a star connection, and a transfer circuit (9a) connects the star point of the first stator system (5) to the star point of the second stator system (6).