Phase Gating Controller Thyristor Re-triggering

Solution Overview

Problem

Phase gating controllers for power control of loads, such as light bulbs and electric motors, face issues with unintended thyristor/triac turn-off due to vibrations or wear, leading to power loss and the need for expensive wiring to maintain control voltage.

Innovation Solution

A phase gating controller with a semiconductor thyristor, sampling device, and control device that switches off control voltage and detects unexpected turn-offs, allowing for re-triggering of the thyristor and reducing power loss, while providing error signals for maintenance alerts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If control voltage is maintained at the triggered thyristor to prevent unexpected turn-off, then reliability of power delivery is improved, but power loss increases and wiring cost increases

Engineering Contradiction:

Improvereliability of power deliveryVSAvoidpower loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The control voltage is applied periodically in short pulses at the beginning of each half-cycle to trigger the thyristor, rather than being continuously applied. This periodic triggering maintains reliability while minimizing power loss and wiring requirements.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The control voltage is applied in advance at the beginning of each half-cycle to ensure the thyristor is triggered before any potential unexpected turn-off can occur. This preliminary action prevents reliability issues without requiring continuous voltage application.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If control voltage is maintained at the triggered thyristor to prevent unexpected turn-off, then reliability of power delivery is improved, but device complexity and wiring cost increase

Engineering Contradiction:

Improvereliability of power deliveryVSAvoidwiring complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control voltage is applied periodically in short pulses at the beginning of each half-cycle to trigger the thyristor, rather than being continuously applied. This periodic triggering maintains reliability while minimizing power loss and wiring requirements.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The control voltage is applied in advance at the beginning of each half-cycle to ensure the thyristor is triggered before any potential unexpected turn-off can occur. This preliminary action prevents reliability issues without requiring continuous voltage application.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the thyristor is quickly triggered only once per half-cycle without re-triggering capability, then device complexity is reduced, but productivity and output power are reduced due to accepted turn-offs

Engineering Contradiction:

Improvedevice complexityVSAvoidoutput power

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The sampling device monitors the voltage across the thyristor's power terminals and provides feedback to the control device. When the sampled voltage exceeds the threshold indicating unexpected turn-off, the control device responds by re-applying the control voltage to re-trigger the thyristor, thereby maintaining output power and productivity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control device is prepared to quickly re-apply the control voltage upon detecting unexpected turn-off, ensuring minimal interruption to power delivery and maintaining high productivity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9705392B2Phase gating controller and method for phase gating control

Publication Date: 2017.07.11 ROBERT BOSCH GMBH

AI summary

A phase gating controller includes a thyristor/triac having a control terminal and two power terminals, a sampling device for sampling a voltage present across the power terminals of the thyristor/triac and a control device configured to provide a control voltage at the control terminal in order to trigger the thyristor/triac. The control device is further configured to switch off the control voltage at the triggered thyristor and to detect an unexpected turning-off of the thyristor/triac if the sampled voltage exceeds a predetermined threshold value.