Roller Test Stand Power Sharing for EV Battery State Control
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Solution Overview
Problem
Existing roller dynamometers face challenges in efficiently testing at least partially electric vehicles, particularly in achieving reproducible results for pollutant gas determination and battery state of charge, due to limitations in energy management and galvanic isolation.
Innovation Solution
A roller dynamometer with a bidirectional power unit and drive supply unit connected via a common intermediate circuit, allowing for efficient energy distribution and charging/discharging of vehicle batteries, while ensuring galvanic isolation through transformers and transistor bridges, enabling optimal energy management and testing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate power supply unit is provided for both engine test bench and battery testing system, then testing functionality is complete, but equipment costs and system complexity increase
Solution Approach 1:
The patent combines the power supply functions for the engine test bench and battery testing system into a single shared power supply unit. This unit can operate in different modes (motor mode and generator mode) to serve both testing functions, thereby reducing equipment costs and system complexity while maintaining complete testing functionality.
Solution Approach 2:
The power supply unit is designed with multi-functionality to serve dual purposes: it can supply power to the engine test bench motor and simultaneously charge or discharge the vehicle battery during testing. This universal design eliminates the need for separate power supply units for each testing system.
2Device complexity
If a single power supply unit is shared for both test systems, then equipment costs are reduced, but energy management complexity and control difficulty increase
Solution Approach 1:
The power supply unit employs dynamic switching between motor mode and generator mode based on real-time testing requirements. The control system automatically adjusts the operational state of the unit to match the energy demands of the test bench and battery testing system, simplifying energy management despite the shared configuration.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor the energy state of both the test bench and battery testing system. This feedback enables the control unit to intelligently manage power distribution, charge/discharge operations, and mode switching, thereby reducing the perceived complexity of energy management.
3Reliability
If galvanic isolation is implemented through transformers and coupling elements, then safety and electrical stability are improved, but device complexity and space requirements increase
Solution Approach 1:
The patent introduces transformers and coupling elements as intermediary components between the power supply unit and the test systems. These intermediaries provide galvanic isolation, ensuring electrical stability and safety while managing the complexity through standardized, modular designs that integrate seamlessly into the existing system architecture.
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 achieves energy-efficient testing by minimizing external energy input, optimizing energy distribution, and ensuring precise control of vehicle battery state, thereby enhancing the reliability and accuracy of testing results.
Implementation Method 1
The coupling element can preferably be a transformer for galvanic isolation
Data Source
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AI summary
The present invention relates to a roller test stand and to a method for operating a roller test stand. The roller test stand for at least partially electrically driven vehicles has a control device which comprises a drive supply unit and a power unit. The drive supply unit A and the power unit B are connected via a common intermediate circuit (4). An energy exchange between the drive supply unit A and the power unit B is thus made possible. The power unit B serves for electrically charging the vehicle battery or for electrically connecting to the vehicle. The drive supply unit A serves to supply an electric machine (6) for driving or decelerating the running roller L of the roller test stand.