Indirect Matrix Converter Rectifier Module Design
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Solution Overview
Problem
Conventional direct matrix converters require nine expensive and voluminous bidirectional switches for bidirectional AC power conversion, leading to high costs and large circuit volumes, which hinders the improvement of power density and reliability.
Innovation Solution
An indirect matrix converter design incorporating a rectifier module with three parallel-connected T-type bridge arms and an inverter module, utilizing a reduced number of bidirectional switches to achieve bidirectional power flow without energy storage capacitors, allowing for efficient voltage and current conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional direct matrix converter uses nine bidirectional switches for bidirectional AC power conversion, then bidirectional power flow capability is achieved, but the cost and circuit volume increase significantly
Solution Approach 1:
The patent segments the bidirectional power conversion function into two separate unidirectional conversion stages: a rectifier module for AC-to-DC conversion and an inverter module for DC-to-AC conversion. This segmentation eliminates the need for nine bidirectional switches by using three T-type bridge arms (each with bidirectional capability through complementary switches) in the rectifier stage and three bridge arms in the inverter stage, thereby reducing circuit volume while maintaining bidirectional power flow capability
Solution Approach 2:
The patent introduces a DC bus as an intermediary energy storage link between the rectifier module and inverter module. This DC bus serves as a mediator that enables bidirectional power flow by allowing power to flow from AC to DC (rectification) or from DC to AC (inversion), eliminating the need for direct bidirectional switching between AC sources while maintaining conversion functionality
2Adaptability or versatility
If nine bidirectional switches are used in a direct matrix converter, then bidirectional AC-to-AC conversion is enabled, but the system cost increases due to the expensive and voluminous switch components
Solution Approach 1:
The patent divides the bidirectional conversion system into separate rectifier and inverter modules, each using standard unidirectional switches (IGBTs or MOSFETs) with anti-parallel diodes to achieve bidirectional current flow. This segmentation replaces the need for expensive integrated bidirectional switches with more cost-effective discrete switch components, reducing overall system cost while maintaining bidirectional power conversion capability
Solution Approach 2:
The patent uses standard, mass-produced unidirectional power switches (IGBTs/MOSFETs) with integrated anti-parallel diodes instead of specialized bidirectional switches. These standard components are more cost-effective and have better availability, reducing the overall system cost while achieving the same bidirectional power conversion function through complementary switching arrangements
Data Source
AI summary
An indirect matrix converter includes a rectifier module, an inverter module, and a control unit. The rectifier module includes three parallel-connected T-type bridge arms, and each T-type bridge arm includes a bidirectional switch and a power bridge arm. The power bridge arm includes a first switch and a second switch connected to the first switch in series. One end of the bidirectional switch is coupled to a first AC power source, and the other end thereof is coupled to a common contact between the first switch and the second switch. The control unit outputs a plurality of control signals to control the rectifier module and the inverter module, so that the first AC power source is converted into a second AC power source, or the second AC power source is converted into the first AC power source.