UPS Rectifier Relay Topology for Low-Cost Mode Switching
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Solution Overview
Problem
Existing uninterruptible power supplies (UPS) with SCR-based mode switching suffer from high circuit costs due to large SCR losses and the need for an isolated drive circuit, and there is a need to reduce these costs while maintaining stability during mode transitions.
Innovation Solution
The UPS employs an interleaved parallel connection of rectifier diodes and relays, eliminating the need for an additional drive circuit and reducing SCR losses, with a charging circuit to maintain voltage stability during mode transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SCR is used for mode switching in UPS, then switching speed is fast and output voltage stability is maintained, but circuit cost increases due to large SCR losses and need for isolated drive circuit
Solution Approach 1:
The patent extracts and removes the SCR component and its associated isolated drive circuit from the UPS system. Instead of using SCR for mode switching, the invention employs a simpler switching mechanism that eliminates the need for these complex and costly components while maintaining the essential function of mode transition between mains and battery power sources.
Solution Approach 2:
The patent replaces the expensive SCR component with lower-cost switching elements that achieve the same mode transition function. The invention uses more economical components that can perform the switching operation without requiring the complex isolated drive circuitry that SCR demands, thereby reducing overall circuit cost.
2Speed
If SCR is used for mode switching in UPS, then switching speed is fast, but energy loss increases due to large SCR losses
Solution Approach 1:
The patent replaces the energy-intensive SCR component with lower-cost, lower-loss switching elements. The alternative switching mechanism uses components that dissipate less energy during operation while maintaining adequate switching speed for UPS mode transitions, thereby reducing overall energy losses in the system.
Solution Approach 2:
The patent changes the electrical parameters of the switching mechanism by replacing SCR with alternative components that have different loss characteristics. This parameter change results in reduced energy loss during mode transitions while maintaining the necessary switching performance for uninterrupted power supply operation.
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 design effectively reduces circuit costs and improves stability by minimizing SCR losses and eliminating the need for an additional drive circuit, while ensuring smooth transitions between mains and battery modes.
Implementation Method 1
The rectifier converts the alternating current supplied by the alternating current power grid into a direct current
Implementation Method 2
The inverter converts the direct current into an alternating current and outputs the alternating current to an output end of the UPS
Implementation Method 3
The UPS employs an interleaved parallel connection of rectifier diodes and relays, eliminating the need for an additional drive circuit
Data Source
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AI summary
This application provides an uninterruptible power supply. A rectifier of the uninterruptible power supply includes six first rectifier diodes, six second rectifier diodes, three alternating current side relays, six direct current side relays, a DC/DC conversion unit, and a controller. The other end of each alternating current side relay is connected to anodes of two first rectifier diodes, and cathodes of the two first rectifier diodes are respectively connected to two phases of positive input ends of the DC/DC conversion unit. The other end of each alternating current side relay is further connected to cathodes of two second rectifier diodes, and anodes of the two second rectifier diodes are respectively connected to two phases of negative input ends of the DC/DC conversion unit. In response to voltage abnormality of three phases of alternating current input ends, the controller controls the DC/DC conversion unit to stop operation, and controls the three alternating current side relays to turn off; and after the three alternating current side relays are turned off for first preset duration, controls the six direct current side relays to turn on. By using this application, circuit costs of the uninterruptible power supply can be reduced.