Bidirectional Switch Power Conversion Device Voltage Control
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Solution Overview
Problem
The existing power conversion devices face issues with increased switching loss due to the operation of switching elements at high voltages, conduction loss through semiconductor elements, and the inability to instantaneously switch control operations during 3-phase alternating current power supply interruptions, leading to inefficiencies and the need for detection and disconnecting mechanisms.
Innovation Solution
A power conversion device that generates a 3-phase alternating current voltage using a direct current power supply and 3-phase alternating current power supply, with line voltage commands synchronized or asynchronous to the terminal voltages, reducing switching and conduction losses by operating bidirectional switch elements between two voltage levels and eliminating the need for interruption detection and disconnecting mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If switching elements operate at high voltages to generate predetermined 3-phase alternating current voltage, then voltage output capability is improved, but switching loss increases
Solution Approach 1:
The patent segments the voltage generation function by using bidirectional switch elements that can operate at multiple voltage levels (0V, +Vdc, -Vdc) rather than requiring single high-voltage switching. This segmentation allows the system to achieve high voltage output capability while switching elements operate at lower voltage differences, reducing switching loss.
Solution Approach 2:
The patent changes the operating parameters of the switching elements by enabling them to switch between multiple voltage levels (0V, +Vdc, -Vdc) rather than operating at a fixed high voltage. This parameter change allows the switching elements to operate at lower voltage differences during switching transitions, thereby reducing switching loss while maintaining the capability to generate predetermined 3-phase alternating current voltage.
2Speed
If semiconductor elements are used for switching operations, then switching speed is improved, but conduction loss occurs
Solution Approach 1:
The patent changes the voltage parameter during switching operations by utilizing bidirectional switch elements that can operate at multiple voltage levels. This allows the switching elements to conduct at lower voltage differences during certain operating modes, reducing conduction loss while maintaining high switching speed through semiconductor elements.
3Reliability
If detection and disconnecting mechanisms are added to handle power supply interruptions, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the bidirectional switch elements multi-functional by enabling them to perform both normal voltage generation and interruption response functions. The same switch elements that generate the predetermined 3-phase alternating current voltage also handle interruption scenarios by switching to alternative voltage sources, eliminating the need for separate detection and disconnecting mechanisms.
Solution Approach 2:
The system uses its own existing components (the bidirectional switch elements and voltage sources) to handle power supply interruptions without requiring external detection or disconnecting mechanisms. The switch elements automatically respond to interruption conditions by switching to alternative voltage sources, making the system self-sufficient in handling failures.
4Power
If switching elements operate at high voltage levels, then voltage generation capability is improved, but switching loss increases
Solution Approach 1:
The patent segments the voltage generation function by using bidirectional switch elements that can operate at multiple voltage levels (0V, +Vdc, -Vdc) rather than requiring single high-voltage switching. This segmentation allows the system to achieve high voltage output capability while switching elements operate at lower voltage differences, reducing switching loss.
Solution Approach 2:
The patent changes the operating parameters of the switching elements by enabling them to switch between multiple voltage levels (0V, +Vdc, -Vdc) rather than operating at a fixed high voltage. This parameter change allows the switching elements to operate at lower voltage differences during switching transitions, thereby reducing switching loss while maintaining the capability to generate predetermined 3-phase alternating current voltage.
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 device achieves reduced power loss, prevents conduction loss, and maintains stable voltage output during interruptions without the need for detection or disconnecting mechanisms, enhancing efficiency and reliability.
Implementation Method 1
a power conversion device that generates a 3-phase alternating current voltage using the voltages of a 3-phase alternating current power supply and direct current power supply
Data Source
Figure 1
Figure 2(a)~2(d)
Figure 3
AI summary
There is provided a power conversion device such that it is possible to supply a constant voltage to a load even when the voltage of a 3-phase alternating current power supply fluctuates. A series circuit formed of a switching element Q1 and switching element Q2 and a series circuit formed of a switching element Q3 and switching element Q4 are connected to both ends of a direct current power supply series circuit 3 formed of a direct current power supply Psp and a direct current power supply Psn, a bidirectional switch element S1 is connected between an alternating current output terminal U and a terminal R, a bidirectional switch element S2 is connected between the alternating current output terminal U and a neutral terminal O, a bidirectional switch element S3 is connected between an alternating current output terminal W and the neutral terminal O, a bidirectional switch element S4 is connected between the alternating current output terminal W and a terminal T, and furthermore, an alternating current output terminal V and terminal S are connected.