Modular Three-Phase AC-AC Converter With Mesh Rectifier Topology
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Solution Overview
Problem
Conventional motor drive systems face challenges in miniaturization and densification due to the requirement of high-voltage resistant semiconductor elements in rectifier circuits, which increases design and manufacturing costs and hinders the use of low-voltage resistant elements.
Innovation Solution
A modularized three-phase AC-AC converter with a mesh-connected rectifier circuit configuration, where multiple rectifier circuit modules are connected via inductors to reduce the voltage resistance of each module, allowing the use of low-voltage resistant circuit elements and achieving miniaturization and densification of the motor drive system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional rectifier circuit with high-voltage resistant semiconductor elements is used, then the circuit can handle high input voltages, but the system size increases and cost increases
Solution Approach 1:
The rectifier circuit is divided into multiple independent modules (first rectifier circuit module, second rectifier circuit module, third rectifier circuit module), each handling a portion of the input voltage. This segmentation allows each module to use low-voltage resistant elements while collectively handling high input voltages through series connection of capacitors in each module.
2Reliability
If high-voltage resistant semiconductor elements are used in the rectifier circuit, then the circuit can operate at high voltages, but manufacturing cost increases
Solution Approach 1:
The rectifier circuit is divided into multiple independent modules (first rectifier circuit module, second rectifier circuit module, third rectifier circuit module), each handling a portion of the input voltage. This segmentation allows each module to use low-voltage resistant elements while collectively handling high input voltages through series connection of capacitors in each module.
3Volume of moving object
If the rectifier circuit is modularized with multiple modules connected via inductors, then low-voltage resistant elements can be used enabling miniaturization, but the circuit complexity increases
Solution Approach 1:
The rectifier circuit is divided into multiple independent modules (first rectifier circuit module, second rectifier circuit module, third rectifier circuit module), each handling a portion of the input voltage. This segmentation allows each module to use low-voltage resistant elements while collectively handling high input voltages through series connection of capacitors in each module.
Solution Approach 2:
Multiple rectifier circuit modules are combined in a mesh-connected configuration where their output capacitors are connected in series. This merging allows the system to achieve high voltage handling capability through the combined effect of multiple low-voltage modules, enabling miniaturization while maintaining functionality.
4Ease of manufacture
If modularized rectifier circuit modules are used, then low-voltage resistant elements can be used reducing cost, but the number of components increases
Solution Approach 1:
The rectifier circuit is divided into multiple independent modules (first rectifier circuit module, second rectifier circuit module, third rectifier circuit module), each handling a portion of the input voltage. This segmentation allows each module to use low-voltage resistant elements while collectively handling high input voltages through series connection of capacitors in each module.
Solution Approach 2:
Each rectifier circuit module is designed with universal functionality to handle a standardized portion of the input voltage. The modules can be replicated and connected in different configurations (three modules for three-phase, six modules for six-phase) to meet different voltage requirements, reducing the need for custom high-voltage designs.
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 modularized rectifier circuit design reduces the voltage resistance of each module, enabling the use of low-voltage resistant elements, thereby achieving miniaturization, densification, and cost reduction in motor drive systems while maintaining smooth motor drive performance.
Implementation Method 1
multiple rectifier circuit modules are connected via inductors to reduce the voltage resistance of each module
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A three phase AC-three phase AC converter (1) includes: n rectifier circuit modules (11), (12), and (13), where n is a multiple of three, that convert a three-phase AC input voltage supplied from a three-phase AC power supply into a DC voltage; and the same number of inverter circuit modules (31), (32), and (33) as the rectifier circuit modules (11), (12), and (13) that convert the DC voltage into a three phase AC output voltage. Three input terminals of each one of the rectifier circuit modules (11), (12), and (13) are connected to an output terminal of each phase of the three-phase AC power supply and respective input terminals of the rectifier circuit modules different from the one of the rectifier circuit modules (11), (12), and (13), respectively, via inductors (20), (20), (21), (22), (23), (24), and (25).