Power Electronics Driver Switch-Off Redundancy

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Solution Overview

Problem

Existing drivers for power electronic switches face challenges in reliably switching off semiconductor switches when the signal transmission path fails or the secondary side voltage supply drops, leading to potential interference and incomplete switch-off due to the limitations of conventional pulse transformer technology.

Innovation Solution

The method involves determining the switching cycle of a switched-mode power supply on the secondary side and generating a switch-off command if it deviates from the target frequency, using a redundant power supply path to ensure safe and reliable switch-off, even in the event of primary side failures or voltage drops, by briefly disrupting the switching clock to create a second transmission path for the switch-off signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pulse transformer technology is used for signal transmission, then the driver can transmit switching signals from primary to secondary side, but the switch-off capability is lost when the signal transmission path fails or voltage supply drops

Engineering Contradiction:
Improveswitch-off capabilityVSAvoidsignal transmission path
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the power supply function and signal transmission function into a single integrated path through the transformer. The transformer serves dual purposes: providing power to the secondary side and transmitting the switch-off signal simultaneously. This eliminates the need for separate redundant signal paths while maintaining reliable switch-off capability even when voltage drops occur.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The transformer is designed to perform multiple functions: power transmission, signal transmission, and fault detection. By making the signal transmission path universal and dependent on the same power supply path, the system ensures that any voltage drop automatically affects both power and signal, preventing false switch-off commands while maintaining the ability to switch off when needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If undervoltage monitoring is implemented on the secondary side, then voltage drops can be detected, but the switch-off may occur after the voltage has already dropped, making the switch susceptible to interference

Engineering Contradiction:
Improvevoltage drop detectionVSAvoidswitch-off timing
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback by monitoring the transformer's output voltage on the secondary side. When the voltage drops below a threshold, the system detects this change and immediately responds by preventing false switch-off commands or by using alternative switch-off paths. This feedback mechanism ensures that switch-off timing is optimized based on real-time voltage conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary detection of voltage drops and takes preventive action before the voltage drops to a critical level. By monitoring the transformer output and detecting voltage changes early, the system can prepare alternative switch-off paths or adjust control parameters to maintain reliable switching operation throughout the voltage transition.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a second switch-off signal is sent to ensure reliable switch-off, then the switch-off reliability improves, but conventional pulse transformer technology does not allow sending a second switch-off signal

Engineering Contradiction:
Improveswitch-off reliabilityVSAvoidsignal transmission flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic control of the transformer's switching behavior. The system can adaptively change the transformer's operation mode based on detected conditions: in normal operation, it transmits standard switching signals; when voltage drops are detected or switch-off reliability is compromised, it dynamically switches to an alternative mode that enables sending a second switch-off signal or maintaining switch-off capability throughout the voltage transition.

Inventive Principle:
Principle #15Dynamics

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 immediate detection of switching cycle deviations and safe switch-off of the electronic power switch before significant voltage drops, providing a more reliable and efficient method compared to traditional undervoltage monitoring, with the added benefit of establishing a redundant switch-off path and maintaining quartz-precise clock synchronization without additional costs.

Implementation Method 1

a switched-mode power supply (SMP) being arranged between the two. The SMP can be operated with a switching cycle and is used to supply power to the secondary side by generating a supply voltage on the secondary side

Methodology Applied
Scientific EffectSwitched-mode power supply operation:

Implementation Method 2

the switching cycle of the SMP is determined on the secondary side from the supply voltage supplied by it. On the secondary side, the switching cycle is monitored with respect to a target frequency

Methodology Applied
Scientific EffectFrequency detection:

Data Source

PatentEP2146423B1Method for operating a driver for a power electronics switch
Publication Date: 2015.09.09 SEMIKRON DANFOSS ELEKTRONIK GMBH & CO KG
  • EP2146423B1 patent drawingFigure 1

AI summary

In a method for operating a driver (2) for a power electronic switch (6), wherein the driver (2) has a switching power supply (14) arranged between its primary (8) and secondary side (10) and operable with a switching clock (fT) for supplying power to the secondary side (10) with a supply voltage (UB), the switching clock (fT) is determined from the supply voltage (UB) on the secondary side (10), and a switch-off command (22) for the switch (6) is generated on the secondary side (10) if the switching clock (fT) deviates from a target frequency (fTS).