AC-DC Converter Circuit for Single- and Three-Phase Voltage Matching
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Solution Overview
Problem
Existing power conversion devices face challenges in maintaining a consistent voltage output and reducing the step-up ratio when switching between single-phase and three-phase AC power supplies, leading to increased losses and inefficiencies.
Innovation Solution
The power conversion device incorporates an AC-DC converter with specific serially-connected bodies, reactors, and a capacitor unit, utilizing ungrounded wires and switches to function as a voltage doubler rectifier circuit, allowing for consistent voltage output regardless of the AC power supply type, thereby reducing the step-up ratio and minimizing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the AC-DC converter is configured to be electrically connectable to both single-phase and three-phase AC power supplies, then the adaptability is improved, but the step-up ratio difference between single-phase and three-phase connections increases significantly
Solution Approach 1:
The AC-DC converter is designed with a universal circuit configuration that can accept both single-phase and three-phase AC power supplies. By using three reactors (L1, L2, L3) and three switching elements (Q1, Q2, Q3) in a symmetric bridge circuit arrangement, the converter maintains consistent voltage output characteristics regardless of whether single-phase or three-phase power is supplied, eliminating the need for different step-up ratios for different power supply types.
2Stability of the object's composition
If the step-up ratio of the AC-DC converter is increased for single-phase power supply connection, then the voltage output consistency is improved, but the losses in the converter increase
Solution Approach 1:
The patent changes the circuit configuration parameters by introducing three reactors and three switching elements in a bridge circuit arrangement. This parameter change enables the converter to achieve adequate voltage conversion with a lower step-up ratio when connected to single-phase power supply, thereby reducing converter losses while maintaining consistent voltage output. The bridge circuit topology allows for more efficient energy transfer compared to conventional single-phase configurations.
3Power
If a high step-up ratio is used in the AC-DC converter for single-phase connections, then the voltage conversion is achieved, but the switching element requirements become more stringent and costly
Solution Approach 1:
The patent segments the voltage conversion function across three switching elements (Q1, Q2, Q3) arranged in a bridge circuit configuration. Instead of requiring a single high-voltage switching element to handle the entire step-up ratio, the segmentation approach distributes the switching stress across multiple elements, each operating at lower voltage stress levels. This makes the switching elements more readily available and less expensive while achieving the same overall voltage conversion capability.
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 ensures a reduced step-up ratio and efficient voltage conversion, bringing the output voltage closer together for single-phase and three-phase connections, and allows for the use of less expensive switching elements by distributing current input effectively.
Implementation Method 1
an AC-DC converter configured to convert input AC power into DC power and output the DC power
Data Source
AI summary
A power conversion device includes an AC-DC converter configured to convert input AC power into DC power and output the DC power, and a capacitor unit connected to the AC-DC converter. The capacitor unit includes a first capacitor, a second capacitor, and a fourth wire. A first end of the first capacitor is connected to a connecting point of three upper arm switching elements. A first end of the second capacitor is connected to a connecting point of three lower arm switching elements. A first end of the fourth wire is connected to a connecting point of the first capacitor and the second capacitor. When the single-phase AC power supply is electrically connected to the AC-DC converter, the fourth wire is used as an ungrounded wire by electrically connecting the second end of the fourth wire to a single-phase AC power supply.