Intermediate Circuit Discharge Branches for Fast Discharge Balancing
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Solution Overview
Problem
Existing intermediate circuit discharge systems for electrical devices, particularly in the automotive sector, face challenges in achieving rapid discharge times and voltage balancing, as they require either active or passive discharge circuits that are not easily controllable or efficient for multi-level converters.
Innovation Solution
A combined intermediate circuit discharge unit with both active and passive discharge branches, where the passive discharge branch controls the active branch, allowing for selective activation and deactivation of the discharge, enabling rapid and controlled discharge functions, including voltage balancing across multiple voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If an active discharge circuit is used to achieve rapid discharge, then discharge time is reduced, but the circuit requires external control signals and becomes more complex
Solution Approach 1:
The passive discharge branch with high-ohmic resistors operates autonomously without requiring external control signals. The branch is permanently conductive and automatically discharges the intermediate circuit capacitor when voltage exceeds a threshold, eliminating the need for control electronics and reducing overall circuit complexity while maintaining rapid discharge capability
Solution Approach 2:
The passive discharge branch is pre-configured with high-ohmic resistors that are always ready to conduct discharge current. This preliminary preparation ensures that discharge can begin immediately without waiting for control signal processing or switch activation, achieving rapid discharge while keeping the control structure simple
2Reliability
If a passive discharge circuit is used for safety, then discharge function is always available, but discharge time increases to 1-5 minutes
Solution Approach 1:
The patent combines both active and passive discharge branches into a single discharge circuit. The passive branch provides continuous safety discharge capability with high-ohmic resistors, while the active branch with low-ohmic resistors provides rapid discharge when needed. Both branches are electrically connected in parallel to the intermediate circuit capacitor, allowing the system to benefit from both the reliability of passive discharge and the speed of active discharge simultaneously
3Loss of time
If an active discharge branch is provided with low-ohmic resistors, then rapid discharge is achieved, but power dissipation increases during operation
Solution Approach 1:
The discharge circuit dynamically switches between different resistance values based on operational requirements. During normal operation, the high-ohmic passive discharge branch is active, providing minimal power dissipation. When rapid discharge is required, the system transitions to using the low-ohmic active discharge branch. This dynamic adaptation allows the system to achieve rapid discharge when needed while minimizing energy loss during normal operation
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 solution provides a simple, efficient discharge mechanism that can be automatically activated without external intervention, ensuring rapid discharge and voltage balancing, even in the absence of external control voltage, enhancing safety and operational efficiency in electrical systems.
Implementation Method 1
The passive discharge branch is always in operation and generates power dissipation
Data Source
AI summary
The invention relates to an intermediate circuit discharge unit for an intermediate circuit discharge, in particular of a multi-level inverter, having a capacitor and a discharge circuit which is connected in parallel, where the discharge circuit has an active discharge branch with at least one first discharge element and a passive discharge branch with at least one second discharge element. The active discharge branch comprises a first control connection, and the passive discharge branch comprises a second control connection. The active discharge branch is coupled to the passive discharge branch via the first control connection in such a way that the active discharge branch can be controlled by the passive discharge branch, in particular a discharge via the active discharge branch can be activated or deactivated as required. The invention further relates to an electrical assembly, a vehicle, as well as a method.