Inverter Shutdown Circuit for Controlled High-Voltage Safe State
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Solution Overview
Problem
Existing inverter control methods in high-voltage networks face challenges in achieving a controlled transition to a safe state without causing undesirable transient currents or voltage fluctuations, particularly when safety-relevant faults occur, leading to immediate shutdowns that stress inverter components.
Innovation Solution
A circuit arrangement comprising a monitoring circuit, microcontroller, gate driver, and redundant shutdown device, which monitors the inverter's status and components, allowing controlled transitions to a safe state through the microcontroller if available, or activating the redundant shutdown device if not, thereby reducing stress on power transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inverter is switched to a safe state (freewheeling or active short circuit) when a safety-relevant fault occurs, then safety integrity is ensured, but immediate shutdown causes high transient currents and voltage fluctuations that stress inverter components
Solution Approach 1:
The monitoring circuit continuously monitors the inverter status and components before a fault occurs, preparing status data for potential controlled shutdown. When a fault occurs, this pre-collected information enables immediate determination of the optimal shutdown path without delay, reducing transient effects while ensuring safety integrity.
Solution Approach 2:
The monitoring circuit acts as an intermediary between the fault detection and shutdown execution. It evaluates the inverter status and components, then determines whether to enable controlled shutdown via microcontroller or immediate shutdown via redundant shutdown device, optimizing the balance between safety and minimizing transient currents.
2Reliability
If immediate shutdown is performed via redundant shutdown device when safety-relevant fault occurs, then safety is ensured, but power transistors must be designed for maximum currents increasing device complexity
Solution Approach 1:
The monitoring circuit provides continuous feedback on the inverter status and component health. This feedback enables the system to determine whether controlled shutdown is feasible, allowing power transistors to be designed for lower maximum currents since controlled shutdown will be used when conditions permit, reducing device complexity while maintaining safety.
3Object-affected harmful factors
If controlled shutdown is attempted via microcontroller, then transient currents are reduced, but shutdown cannot occur if monitoring level detects safety-relevant fault
Solution Approach 1:
The shutdown mechanism dynamically adapts based on real-time monitoring of inverter status and components. The system can switch between controlled shutdown (when status permits) and immediate shutdown (when status indicates danger), ensuring both reduced transient currents and reliable shutdown capability under all fault conditions.
Solution Approach 2:
The monitoring circuit performs beforehand evaluation of the inverter status to determine if controlled shutdown is safe. This pre-evaluation cushions against attempting controlled shutdown when it would be dangerous, while still enabling the benefits of controlled shutdown when conditions are favorable.
Data Source
Figure 1
AI summary
The invention relates to a circuit arrangement (10) for controlling an inverter (3) in a high-voltage network, wherein the inverter (3) is connected to an electric machine (4) and a high-voltage battery (2), wherein the circuit arrangement (10) comprises at least one microcontroller (12), at least one monitoring circuit (11) for the microcontroller (12), at least one gate driver module (13) for the inverter (3), and a redundant shutdown device (15) for performing a shutdown operation of the inverter (3), wherein the monitoring circuit (11) is configured to receive at least status data (ZD) of the at least one gate driver module (13) and the inverter (3), and wherein the monitoring circuit (11) is configured to monitor the availability of the microcontroller (12) in the event of a fault in which the electric machine (4) must be brought into a safe state.to check the at least one gate driver module (13) and the inverter (3) to see if a controlled or regulated transfer of the electric machine (4) via the microcontroller (12) is possible, wherein, if this is not possible, the shutdown process is carried out via the redundant shutdown device (15) and otherwise the shutdown process is initiated by the microcontroller (12), wherein the monitoring circuit (11) is further configured to monitor the shutdown process by the microcontroller (12) and, in the event of a fault, to carry out the shutdown via the redundant shutdown device (15), as well as a method for controlling an inverter (3).