AC Source Switching Control with Transistor Pairs for Fast Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional automatic switching switches using relays and silicon controlled rectifiers (SCR) face issues with long switching durations, inability to handle transient currents, and require multiple components, leading to complex architectures that increase costs and complexity.
Innovation Solution
A switching control system utilizing pairs of transistor switches connected in reverse series to form a two-way switch, allowing for quick switching between power supply and backup alternating currents, eliminating the need for relays and SCR, and preventing short-circuiting during transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a relay is used as the switch in the automatic switching switch, then the switching switch can be implemented with a simple structure, but the switching duration becomes too long and the relay cannot withstand great transient current
Solution Approach 1:
The patent replaces the mechanical relay switch with electronic transistor switches (Q1-Q4) that operate without mechanical moving parts. This substitution eliminates the inherent mechanical limitations of relays, achieving both fast switching duration and the ability to withstand transient currents while maintaining structural simplicity through the use of standard electronic components.
2Reliability
If an SCR and diode are added to withstand transient current, then the transient current capability is improved, but the quantity of components increases
Solution Approach 1:
The patent makes the transistor switches serve multiple functions: they act as the primary switching elements, withstand transient currents through their inherent current handling capability, and provide bidirectional current control. This multi-functionality eliminates the need for separate SCR and diode components, reducing overall component quantity while improving transient current capability.
Solution Approach 2:
The patent changes the operating parameters of the transistor switches by connecting them in reverse series configuration, allowing them to handle bidirectional currents and transient voltage spikes. This parameter change enables the transistors to withstand transient currents without requiring additional protective components like diodes or SCRs.
3Reliability
If a diode is added to prevent reverse current through the transistor switch, then the reverse current protection is improved, but the quantity of components increases
Solution Approach 1:
Instead of adding a diode to block reverse current, the patent inverts the approach by connecting transistor switches in reverse series configuration. This allows the transistors themselves to handle bidirectional currents safely, with the control circuit managing the switching timing to prevent harmful reverse current flow. This inversion eliminates the need for additional diode components.
4Reliability
If a rectifier circuit is added to rectify alternating power supply into direct current, then the voltage handling capability is improved, but the architecture becomes more complex and additional components are required
Solution Approach 1:
The patent replaces the rectifier circuit approach with a direct AC switching architecture using transistor switches. The transistors are controlled to switch during specific half-cycles of the AC waveform, achieving voltage management and protection without rectification. This substitution maintains voltage handling capability while eliminating the complexity of rectifier circuit components.
Data Source
AI summary
A switching control system, including: switch units, configured to separately receive one of alternating currents and couple to a load; a detection unit, configured to detect the alternating currents; and a control unit, configured to, after receiving a switching signal, and in response to detecting that a power supply alternating current and a backup alternating current are in a polarity half cycle and a voltage difference is less than a preset voltage, perform: closing a first turn-on direction of a power supply switch unit; opening a second turn-on direction of a backup switch unit; closing a second turn-on direction of the power supply switch unit; and opening a first turn-on direction of the backup switch unit; where the first turn-on direction is opposite to a direction of the polarity half cycle, and the second turn-on direction is the same as the direction of the polarity half cycle.