Uninterruptible Power Supply Rectifier Boost Circuit Transistor Configuration
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Solution Overview
Problem
Existing uninterruptible power supplies (UPS) using a single battery in a split DC bus rectifier converter circuit face inefficiencies and increased component count, particularly in switching transistors, which affect performance and cost-effectiveness.
Innovation Solution
The implementation of a rectifier/boost circuit with a relay configuration that allows a single transistor to function in both line and battery modes, reducing the number of transistors and diodes, and incorporating additional components to minimize switching losses, such as transistor 381 and diode 377, which reduce the current rating requirements and operational losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single battery is used in a split DC bus rectifier converter circuit with traditional relay configuration, then cost is reduced, but component count increases and switching losses increase
Solution Approach 1:
Transistor Q188 is configured to perform multiple functions: it operates as a switch in the positive boost circuit during line mode, and as a switch in the negative boost circuit during battery mode. This multi-functionality eliminates the need for dedicated transistors in each circuit, reducing overall component count while maintaining circuit functionality.
Solution Approach 2:
Relay 288 acts as an intermediary component that couples transistor Q188 to different circuits depending on operating mode. During line mode, it connects Q188 to the positive boost circuit; during battery mode, it connects Q188 to the negative boost circuit. This intermediary mechanism enables the single transistor to serve both circuits without direct permanent connections, reducing switching losses.
2Strength
If traditional relay configuration is used to couple single battery to dual DC buses, then circuit simplicity is maintained, but transistor current rating requirements increase
Solution Approach 1:
Transistor Q188 serves dual purposes across different operating modes, handling current in the positive boost circuit during line mode and in the negative boost circuit during battery mode. This universality allows the use of a single transistor with moderate current ratings rather than requiring parallel high-current transistors for each circuit.
Solution Approach 2:
Relay 288 mediates the connection between transistor Q188 and the boost circuits, ensuring that the transistor handles current only in its designated mode. This intermediary arrangement prevents the transistor from needing to handle the combined current of both circuits simultaneously, reducing the required current rating.
3Quantity of substance
If a single transistor is used in both line and battery modes, then component count is reduced, but reliability may be affected
Solution Approach 1:
Relay 288 provides electrical isolation between transistor Q188 and the different boost circuits during mode transitions. By controlling when Q188 is connected to the positive or negative circuit, the relay prevents voltage spikes and current surges from affecting the transistor, thereby maintaining reliability despite the reduced component count.
Solution Approach 2:
The control circuit is configured to turn off transistor Q188 before relay 288 switches connections during mode transitions. This beforehand action prevents voltage spikes and current surges that would otherwise occur during switching, protecting the transistor and maintaining system reliability.
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 provides similar performance to prior systems with reduced component count and lower current ratings, enhancing cost-effectiveness and efficiency in both line and battery modes of operation.
Implementation Method 1
a boost circuit configured to provide a positive output DC voltage with respect to the input neutral connection and a negative output DC voltage with respect to the input neutral connection
Data Source
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AI summary
At least one aspect of the invention is directed to an uninterruptible power supply. The uninterruptible power supply includes a first input having an input line connection and an input neutral connection to receive a first input voltage from a first voltage source, a second input having a positive input connection and a negative input connection to receive a second input voltage from a second voltage source, a boost circuit configured to provide a positive output DC voltage with respect to the input neutral connection and a negative output DC voltage with respect to the input neutral connection in both a line mode of operation and a backup mode of operation, a first connection circuit configured to couple the first input to the boost circuit in the line mode of operation, and configured to couple the second input to the boost circuit in the backup mode of operation, and a second connection circuit configured to couple a midpoint of the boost circuit to the input neutral connection in the line mode of operation and to couple the midpoint of the boost circuit to the positive input connection in battery mode of operation.