Electric Vehicle Drive System Energy Flow Control
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Solution Overview
Problem
In electric vehicle drive systems, maintaining optimal operation of multiple electrical energy stores with different states of charge is challenging, and existing systems lack efficient methods to maximize overall efficiency and minimize losses during energy transfer between energy sources and electric machines.
Innovation Solution
A method and drive system that dynamically selects operating modes based on the state of charge of the second energy source, allowing electrical energy transfer between a first energy source, a second energy source (such as lithium ion batteries), and electric machines, optimizing energy flow to ensure maximum efficiency by charging or discharging as needed, with predefined charging power based on rotational speed and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrical energy is transferred between multiple energy sources and electric machines to optimize operation, then overall system efficiency is improved, but system complexity increases due to multiple operating modes and control requirements
Solution Approach 1:
The patent implements dynamic operating modes that adapt to the state of charge of energy sources. The system transitions between different operational configurations (first operating mode with both energy sources discharging, second operating mode with one source discharging and one charging, third operating mode with only one source discharging) based on real-time conditions, optimizing energy efficiency while managing complexity through adaptive control
Solution Approach 2:
The system changes operational parameters including the state of charge thresholds, power distribution ratios, and operating modes based on the energy sources' states. By dynamically adjusting these parameters, the system maximizes efficiency across varying conditions without requiring overly complex hardware architecture
2Reliability
If the state of charge of multiple energy stores is maintained at approximately the same level for optimal operation, then energy source reliability is improved, but control complexity increases
Solution Approach 1:
The control unit continuously monitors the state of charge of each energy source and adjusts the operating mode accordingly. Feedback loops compare actual state of charge levels against target ranges and modify power distribution to maintain reliability, using simple threshold-based control logic rather than complex algorithms
Solution Approach 2:
The patent divides the control strategy into distinct operating modes with clear boundaries and transition criteria. Each mode has specific control rules for power distribution, making the overall control system more manageable and less complex than a fully integrated continuous control approach
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 approach allows for efficient charging of depleted energy sources during travel without additional hardware, minimizing losses and ensuring maximum overall efficiency across various operating modes, suitable for six-phase or multi-phase electric machines and systems with multiple energy sources.
Implementation Method 1
When the electric vehicle is braked, the electric machines act as generators and feed generated recuperation energy back into the electrical energy store
Implementation Method 2
Such an electrical energy store can, for example, be charged with electrical energy at an external charging station. To drive the electric vehicle, the electrical energy store then discharges electrical energy to the electric machines
Data Source
AI summary
A method for operating a drive system (10) of an electric vehicle, comprising a first energy source (21), a second energy source (22) formed as an electrical energy store, and at least one electric machine (30) is disclosed. In a first operating mode, electrical energy is transferred from the first energy source (21) to at least one electric machine (30), and electrical energy is transferred from the second energy source (22) to at least one electric machine (30). In a second operating mode, electrical energy is transferred from the first energy source (21) to at least one electric machine (30), and electrical energy is transferred from at least one electric machine (30) to the second energy source (22).