Traction Battery Current Control via Rectifier Feed
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Solution Overview
Problem
Existing traction systems for electric rail vehicles incur switching losses and increased costs, weight, and complexity due to the active switching of DC converters for regulating battery currents, which are necessary for charging and powering traction batteries independently of mains voltage.
Innovation Solution
A method where the battery current is regulated directly through the intermediate circuit voltage regulator, eliminating the need for a separate DC converter by using the rectifier unit to set a predefined feed current, which automatically adjusts the battery current, thereby avoiding switching losses and simplifying the system architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate DC converter is used to regulate battery current, then the battery current can be precisely controlled, but switching losses increase and system complexity increases
Solution Approach 1:
The patent extracts the battery current control function from the separate DC converter and integrates it into the intermediate circuit voltage regulator. This eliminates the need for active switching of a dedicated DC converter, thereby reducing switching losses while maintaining precise battery current control through the unified voltage regulator that simultaneously manages both intermediate circuit voltage and battery current.
Solution Approach 2:
The patent merges the battery current control function with the intermediate circuit voltage regulation function in a single controller. By combining these two control tasks into one voltage regulator, the system eliminates the separate DC converter and its associated switching losses, while still achieving precise control of both intermediate circuit voltage and battery current through integrated control algorithms.
2Measurement precision
If a separate DC converter is used to regulate battery current, then the battery current can be precisely controlled, but system complexity and cost increase
Solution Approach 1:
The patent extracts the battery current control function from the separate DC converter and integrates it into the intermediate circuit voltage regulator. This eliminates the need for active switching of a dedicated DC converter, thereby reducing switching losses while maintaining precise battery current control through the unified voltage regulator that simultaneously manages both intermediate circuit voltage and battery current.
Solution Approach 2:
The patent merges the battery current control function with the intermediate circuit voltage regulation function in a single controller. By combining these two control tasks into one voltage regulator, the system eliminates the separate DC converter and its associated switching losses, while still achieving precise control of both intermediate circuit voltage and battery current through integrated control algorithms.
3Measurement precision
If a separate DC converter is used to regulate battery current, then the battery current can be precisely controlled, but installation space and weight increase
Solution Approach 1:
The patent merges the battery current control function with the intermediate circuit voltage regulation function in a single controller. By combining these two control tasks into one voltage regulator, the system eliminates the separate DC converter and its associated switching losses, while still achieving precise control of both intermediate circuit voltage and battery current through integrated control algorithms.
4Stability of the object's composition
If the rectifier unit regulates intermediate circuit voltage only, then the voltage can be kept constant, but battery current cannot be automatically adjusted
Solution Approach 1:
The patent makes the intermediate circuit voltage regulator multi-functional by enabling it to simultaneously perform both intermediate circuit voltage regulation and battery current control. The controller dynamically adjusts the rectifier unit's feed current based on both voltage regulation needs and battery charging requirements, allowing the system to maintain stable intermediate circuit voltage while automatically adapting the battery current to optimal charging levels.
Solution Approach 2:
The patent implements a feedback control mechanism where the voltage regulator monitors both intermediate circuit voltage and battery current, and dynamically adjusts the rectifier unit's feed current accordingly. This feedback loop enables the system to maintain stable voltage while automatically adapting battery charging current to optimal levels, resolving the contradiction between voltage stability and current adaptability.
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 reduces costs, installation space, and weight by eliminating the DC converter, saves energy, and allows for efficient and dynamic control of battery currents, ensuring reliable and fail-safe operation while minimizing harmonic issues in the intermediate circuit.
Implementation Method 1
a rectifier unit of the traction system converts a mains voltage into a controllable intermediate circuit voltage of an intermediate circuit of the traction system by means of a predefinable feed current
Implementation Method 2
An intermediate circuit voltage regulator regulates an actual voltage value of the intermediate circuit voltage to a desired voltage value of the intermediate circuit voltage
Implementation Method 3
A battery current regulator regulates an actual current value of the battery current to a desired current value of the battery current
Data Source
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AI summary
The invention relates to a method for controlling a battery current of a traction battery of a traction system. A rectifier unit of the traction system converts a network voltage into a controllable intermediate circuit voltage of a second circuit of the traction system using a specifiable feed current. An intermediate circuit voltage controller controls an actual value of the intermediate circuit voltage to attain a setpoint value of the intermediate circuit voltage and specifies a first output variable. A battery current controller controls an actual value of the battery current to attain a setpoint value of the battery current and specifies a second output variable. The second output variable of the battery current controller is applied to the first output variable of the intermediate circuit voltage controller in order to form a specification variable for the feed current, the feed current specified by the specification variable being used to readjust the actual value of the battery current in order to control said current.