Zero-Crossing SSR Bypass Switching for Inrush and Surge Suppression
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Solution Overview
Problem
In industrial environments, equipment faces damage from inrush current and surge voltage when power is applied or interrupted, which existing technologies fail to effectively suppress.
Innovation Solution
An electronic device equipped with a solid state relay (SSR) and a bypass circuit, featuring a zero-crossing detector, that selectively connects and disconnects input and output terminals based on zero voltage detection to manage power supply initiation and interruption, thereby preventing damage from inrush current and surge voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power supply is directly connected without SSR and bypass circuit, then device complexity is reduced, but inrush current and surge voltage damage equipment
Solution Approach 1:
The bypass circuit is activated before the SSR when power is turned on, allowing power to flow through the bypass initially. After a first period, the SSR is turned on to take over power conduction, and after a second period, the bypass is turned off. This preliminary action sequence prevents inrush current by gradually transitioning power flow through different paths.
Solution Approach 2:
The SSR acts as an intermediary device between the power source and the load, controlling power flow through zero-crossing detection. The bypass circuit serves as another intermediary path that can be activated or deactivated based on control signals. These intermediary devices enable smooth power transitions without direct connection shocks.
2Speed
If SSR is turned on immediately upon power supply interruption command, then response speed is improved, but surge voltage occurs due to abrupt disconnection
Solution Approach 1:
When power interruption is commanded, the controller first turns on the SSR and waits for a first period to elapse before turning off the bypass circuit. This preliminary action allows the SSR to be ready and in position before the bypass is deactivated, enabling controlled power transfer and preventing surge voltage while maintaining fast response.
Solution Approach 2:
The controller implements periodic timing actions: waiting for a first period after turning on the SSR before turning off the bypass, and waiting for a second period after turning off the bypass before turning off the SSR. This periodic action sequence ensures smooth power interruption by coordinating the switching timing of different components.
3Stability of the object's composition
If bypass circuit is turned off immediately after SSR activation, then power supply stability is improved, but inrush current occurs due to uncontrolled transition
Solution Approach 1:
The controller waits for a first period after turning on the SSR before turning off the bypass circuit. This preliminary waiting period ensures that the SSR is fully activated and stable before the bypass is deactivated, allowing controlled power transition and preventing inrush current while maintaining supply stability.
Solution Approach 2:
The controller uses timing feedback mechanisms to coordinate the switching of SSR and bypass circuit. By monitoring the lapse of first and second periods, the controller ensures proper sequencing and timing, providing feedback control that prevents harmful current surges during transitions.
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 suppresses inrush current and surge voltage during power application and interruption, protecting equipment from potential damage by utilizing the SSR to connect and disconnect power at zero voltage points, ensuring safe and reliable power management.
Implementation Method 1
the zero-crossing detector is configured to detect a zero voltage of a voltage associated with at least one voltage of the input terminal and/or the output terminal
Implementation Method 2
a solid state relay (SSR) configured to selectively connect the input terminal and the output terminal... when the SSR is on, the SSR is configured to release a connection between the input terminal and the output terminal when the zero-crossing detector detects substantially 0V at the input terminal
Implementation Method 3
a bypass circuit connected in parallel to the SSR and configured to selectively connect the input terminal and the output terminal
Data Source
AI summary
According to various embodiments, an electronic device comprises: an input terminal configured to receive alternating current (AC) power from an external source; an output terminal configured to output the AC power; a solid state relay (SSR) configured to selectively connect the input terminal and the output terminal, the SSR comprising a zero-crossing detector, wherein the zero-crossing detector is configured to detect a zero voltage of a voltage associated with at least one voltage of the input terminal and/or the output terminal; a bypass circuit connected in parallel to the SSR and configured to selectively connect the input terminal and the output terminal; and a controller, wherein the controller is configured to: obtain a power supply interruption command while supplying the AC power to the output terminal via the bypass circuit, turn on the SSR, based on the obtaining of the power supply interruption command, turn off the bypass circuit, based on the lapse of a first period after turning on the SSR, and turn off the SSR, based on the lapse of a second period after turning off the bypass circuit, and wherein when the SSR is on, the SSR is configured to release a connection between the input terminal and the output terminal when the zero-crossing detector detects substantially 0V at the input terminal.