Hybrid Vehicle Propulsion System Voltage Optimization
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Solution Overview
Problem
Existing hybrid vehicle propulsion systems experience efficiency losses due to voltage differentials across boost converters and potential losses from diodes, which are not adequately addressed in current technologies.
Innovation Solution
A propulsion system that includes a first energy storage system coupled to a DC-link, a boost converter, and a second energy storage system with a contactor that can be reversibly coupled to the boost converter, featuring a high-specific energy battery and a second energy source with an operating voltage higher than the battery but lower than the first energy source, to minimize losses and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a boost converter is used to address voltage differential between battery and electric motor, then voltage compatibility is improved, but efficiency loss increases
Solution Approach 1:
A second energy source with intermediate voltage level is introduced between the low-voltage battery and high-voltage electric motor. This intermediary energy source reduces the voltage differential that the boost converter must handle, thereby minimizing efficiency losses while maintaining voltage compatibility.
Solution Approach 2:
The system changes the voltage parameter distribution by adding a second energy source with specific voltage characteristics. This creates a staged voltage transformation approach where the boost converter operates with a smaller voltage differential, reducing energy losses during conversion.
2Reliability
If diodes are included in the boost converter circuit, then circuit functionality is improved, but potential loss opportunities increase
Solution Approach 1:
The invention changes the operating parameters of the boost converter by introducing an intermediate voltage stage. This allows the converter to operate in a more efficient parameter range, reducing the impact of diode-related losses while maintaining necessary circuit functionality.
3Device complexity
If a single energy storage system is used, then system complexity is reduced, but responsiveness and power delivery are limited
Solution Approach 1:
The energy storage system is segmented into two distinct energy sources with different voltage levels and characteristics. This segmentation allows each energy source to be optimized for specific functions, improving overall system responsiveness and power delivery capability.
Solution Approach 2:
The dual energy storage system provides multi-functionality by enabling different operating modes: the first energy source can handle high-power demands while the second energy source manages voltage transformation and intermediate power needs, creating a versatile powertrain system.
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
The system reduces efficiency losses by optimizing voltage differentials and internal resistance losses, improving responsiveness and power delivery to the electric motor, thereby increasing overall system efficiency and reducing energy waste.
Implementation Method 1
a boost converter coupled to the DC-link... a bi-directional boost converter allows the high-voltage side to communicate with the low-voltage side of the circuit
Implementation Method 2
a contactor that is poled to conduct current from a low voltage side of a boost converter to a high voltage side of the boost converter
Implementation Method 3
a first energy storage system electrically coupled to a DC-link, and the first energy storage system comprises a first energy source that can exchange electrical power with an electric motor
Data Source
AI summary
A system includes a first energy storage system electrically coupled to a DC-link, and the first energy storage system comprises a first energy source that can exchange electrical power with an electric motor through the DC-link; a boost converter coupled to the DC-link; a second energy storage system that can be reversibly electrically coupled to the boost converter through a contactor, and wherein an operating voltage of the second energy storage system is less than an operating voltage of the first energy source; and the second energy storage system comprises both an energy battery and a second energy source, and the second energy source has an operating voltage that is higher than the energy battery and is lower than the first energy source operating voltage. A vehicle incorporating the system and a related method are provided.