Power Source Switching Module with Relay-Semiconductor Coordination
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Solution Overview
Problem
Power supply systems with mechanical relays for switching between AC power sources face delays due to response times and the need for monitoring AC voltage waveforms, extending the time required to switch between sources.
Innovation Solution
Incorporating semiconductor switches in parallel with mechanical relays and a controller that manages their connection and disconnection based on input voltage determinations, allowing for faster switching by adjusting determination periods and reducing the time needed to switch between power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical relays are used to switch among AC power sources, then the switching system is simple and reliable, but the response time is slow due to mechanical relay response time and waveform monitoring requirements
Solution Approach 1:
The controller determines whether the AC power source waveform is abnormal before the determination period elapses, and outputs a control signal to the mechanical relay in advance. This preliminary action allows the relay to start switching before the full determination period completes, reducing the overall switching time while maintaining reliable abnormality detection
Solution Approach 2:
A capacitor is connected between the mechanical relay and the AC power source to suppress voltage transients during switching. This intermediary component allows for faster switching by reducing the impact of transient voltages, enabling the system to switch power sources more quickly without compromising reliability
2Reliability
If the waveform of AC voltage is monitored for a preset determination time to eliminate sudden noises, then the abnormality detection is accurate, but the switching time is extended due to the monitoring duration
Solution Approach 1:
The controller performs waveform monitoring for a preset determination time to accurately detect abnormalities, but outputs the control signal to the mechanical relay before the determination period fully elapses. This partial action approach maintains reliable detection while reducing the effective switching time by initiating the relay switching process early
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
This configuration reduces the time required to switch between power sources by enabling earlier detection and response to abnormal voltage conditions, thereby minimizing delays and potential malfunctions.
Implementation Method 1
a semiconductor switch coupled between the mechanical relay and the AC power source. The controller outputs a control signal to the semiconductor switch in accordance with the determination result
Implementation Method 2
a mechanical relay coupled between the AC power source and the subsequent circuit. The controller outputs a control signal to the mechanical relay in accordance with the determination result
Implementation Method 3
a voltage detector to detect an input voltage to the subsequent circuit, and a controller configured to output a control signal to the mechanical relay in accordance with a determination result obtained by determining whether an AC power source waveform inputted to the subsequent circuit is abnormal
Data Source
AI summary
A switching module includes mechanical relays, semiconductor switches, voltage detectors to detect an input voltage to a power converter, and a controller. When the controller determines that the waveform of the input voltage is abnormal during a first determination period, the controller outputs an open command signal to mechanical relays corresponding to a power source electrically coupled to the power converter. When the controller subsequently determines that the waveform of the input voltage is normal during a second determination period, the controller outputs a close command signal to the mechanical relays.