Bidirectional Power Switch Gate Separation
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Solution Overview
Problem
Bidirectional power switches face challenges in preventing inadvertent starting of inactive thyristors due to carrier transfers during charge recovery, especially when current and voltage slopes are high, leading to reduced switching performance and increased costs due to the need for oversized switches and additional filtering circuits.
Innovation Solution
A bidirectional power switch design featuring anode gate and cathode gate thyristors connected in antiparallel with their gates connected to a single control terminal and separated by resistors or diodes to prevent parasitic currents, allowing for improved switching performance without complex control circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If bidirectional power switches use antiparallel thyristors with shared control terminal, then device complexity is reduced, but parasitic currents cause inadvertent starting of inactive thyristors
Solution Approach 1:
Resistors or diodes are introduced as intermediary components between the gates of the first and second thyristors. These intermediaries block parasitic currents during charge recovery, preventing inadvertent triggering of the inactive thyristor while allowing the simplified shared control terminal configuration to remain.
2Speed
If high current and voltage slopes are used in switching, then switching speed is improved, but carrier transfers increase causing inadvertent thyristor starting
Solution Approach 1:
The resistor or diode placed between the thyristor gates acts as a mediator that blocks the harmful carrier transfers generated during high-speed switching. This allows the system to maintain high current and voltage slopes for fast switching while preventing the adverse effect of inadvertent thyristor triggering.
3Reliability
If oversized switches and filtering circuits are added to prevent inadvertent starting, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
Instead of using complex filtering circuits or oversized components, the invention employs simple resistor or diode intermediaries between the gates. These minimal components provide the necessary protection against inadvertent starting, achieving high reliability without increasing device complexity or cost.
Data Source
Figure 1~4
AI summary
The invention relates to a bidirectional power switch comprising first (AGT) and second (TH) thyristors connected in antiparallel between first (A1) and second (A2) conduction terminals of the switch, the first thyristor (AGT) being an anode-gate thyristor, the second thyristor (TH) being a cathode-gate thyristor, and the gates (GAGT, GTH) of the first (AGT) and second (TH) thyristors being connected to the same control terminal (G) of the switch, in which at least one diode (C1, C2) or at least one resistor (C1, C2) separates the gate (GAGT) of the first thyristor (AGT) from the gate (GTH) of the second thyristor (TH).