Hybrid Relay and IGBT Switching Device for Arc Suppression
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Solution Overview
Problem
High power switching devices face challenges in minimizing on-state dissipation losses and preventing electric arcs when switching high currents and voltages, particularly in hybrid electric vehicles, due to limitations in MOSFETs, IGBTs, and relays.
Innovation Solution
A switching device combining a relay with a parallel power semiconductor switch, such as an IGBT, which takes over current from the relay during switch-off to clamp voltage and prevent arcs, and uses a sequence control circuit with mechanical inertia to ensure timely switching without external control, reducing power losses and eliminating the need for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If MOSFETs are used as power semiconductor switches, then switching speed is improved, but on-state resistance causes high dissipation losses
Solution Approach 1:
The patent divides the switching function into two separate components: a relay for main power switching and a power semiconductor switch for voltage clamping. This segmentation allows each component to optimize for its specific function, with the relay providing low on-state resistance and the semiconductor switch enabling fast voltage clamping during turn-off.
2Loss of energy
If relays are used for switching high electrical power, then on-state resistance is reduced, but electric arcs are generated between contacts
Solution Approach 1:
The power semiconductor switch acts as an intermediary that clamps the voltage between relay contacts during turn-off, preventing electric arcs. The semiconductor switch absorbs the voltage spike that would otherwise cause arcing between the relay contacts, protecting the relay from damage.
Solution Approach 2:
The power semiconductor switch is activated in advance during the relay turn-off process to preemptively clamp the voltage before arc formation can occur. This preliminary action prevents the harmful effect of electric arcs before they can develop.
3Power
If IGBTs are used as power semiconductor switches, then switching capability is improved, but on-state voltage causes high dissipation losses
Solution Approach 1:
The patent segments the power switching function between a relay that handles the main power conduction and an IGBT that provides voltage clamping during transient conditions. This allows the relay to provide low-loss conduction while the IGBT handles only the brief voltage clamping function during switching transitions.
4Loss of energy
If parallel connection of MOSFETs is used to reduce on-state resistance, then power dissipation is reduced, but device complexity and cost increase
Solution Approach 1:
The patent uses a single power semiconductor switch (IGBT or MOSFET) that operates only during transient switching conditions rather than continuous conduction. This approach is more cost-effective than using multiple parallel MOSFETs, as it requires only one semiconductor device while achieving the same power loss reduction through the relay's low on-state resistance.
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 solution effectively prevents electric arcs and minimizes power dissipation, ensuring safe and efficient switching operations in high power applications by providing a low-loss current path and reducing the risk of relay damage.
Implementation Method 1
the power semiconductor switch arranged in parallel to the relay, to clamp a voltage between the contacts of the relay during a switch-off operation of the relay
Implementation Method 2
the normally closed contacts of the relay, to provide a low-resistance current path between an input terminal and an output terminal
Implementation Method 3
a coil arranged between the power supply terminal and the power supply neutral terminal, to actuate the relay switch
Data Source
AI summary
Embodiments of the invention relate to a switching device, a high power supply system and methods for switching high power including a relay and a power semiconductor switch arranged in parallel to the relay.