Bidirectional Power Switch Topology for Low-Resistance Overvoltage Protection
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Solution Overview
Problem
Existing power semiconductor switches face high resistance, leading to heating issues and the need for cooling arrangements, and silicon MOSFETs are not rugged enough for rapid avalanche breakdowns, necessitating multiple TVS diodes for protection, which are expensive.
Innovation Solution
A bidirectional power semiconductor switch using parallel-connected silicon or silicon-carbide MOSFETs and IGBTs, controlled by a driver unit, reduces resistance and eliminates the need for cooling, while a single varistor protects against overvoltage, avoiding avalanche breakdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a transistor is used as the main switching part in a power semiconductor switch, then the switch can be controlled electronically, but the interposed resistance is high causing heating and requiring cooling arrangements
Solution Approach 1:
The patent combines a mechanical switch with a transistor in a hybrid circuit breaker configuration. The mechanical switch handles the main current path with low resistance, while the transistor provides electronic control capability for switching operations. This merging allows the system to benefit from both low resistance (reducing heating) and electronic controllability without requiring complex cooling arrangements.
2Reliability
If multiple TVS diodes are placed to protect silicon MOSFETs against avalanche breakdown, then the MOSFETs are protected, but the cost increases significantly
Solution Approach 1:
The patent extracts the protection function from multiple expensive TVS diodes and implements it through a single varistor in combination with the hybrid switch configuration. The varistor provides overvoltage protection while the mechanical switch portion of the hybrid configuration protects against avalanche breakdown, eliminating the need for multiple TVS diodes and significantly reducing manufacturing cost while maintaining reliability.
3Loss of energy
If the resistance of the power semiconductor switch is reduced, then power losses decrease, but the device complexity increases due to parallel semiconductor arrangements
Solution Approach 1:
The patent merges a mechanical switch with a transistor in parallel to create a hybrid circuit breaker. This configuration reduces the overall resistance and power losses by utilizing the low resistance path of the mechanical switch during conduction, while avoiding the complexity of arranging multiple semiconductor devices in parallel. The hybrid configuration achieves low power losses with simpler device 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
The switch achieves low resistance and safe operation, eliminating the need for cooling and reducing power losses, with a single varistor providing effective overvoltage protection and extending the switch's lifetime.
Implementation Method 1
a varistor (10) connected between a collector terminal of the IGBT and a common terminal, such that the varistor (10) limits overvoltage in the conductor path
Implementation Method 2
at least a first silicon or silicon-carbide MOSFET (8) and a first IGBT (9) connected parallel to each other in a first semiconductor circuit arrangement (11) in the first outer conductor path (2)
Data Source
AI summary
Some embodiments relate to a bidirectional power semiconductor switch with a first semiconductor circuit arrangement including a first Si or SiC MOSFET and a second Si or SiC MOSFET and a parallel connected first IGBT and a second IBGT.A control and driver unit controlling the first and the second silicon or silicon-carbide MOSFETs and the first and the second IGBTs is suggested, that, in a turning on process of the bidirectional power semiconductor switch, the control and driver unit is embodied to switch on at least one of the IGBTs in a first step, and to switch on at least one of the silicon or silicon-carbide MOSFET in a second step, and/or that—in an on-state of the bidirectional power semiconductor switch—the control and driver unit is embodied to keep the previously turned on silicon or silicon-carbide MOSFET and the corresponding IGBT in the on-states.