Three-Phase AC/DC Converter Using Segmented Boost Circuits
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Solution Overview
Problem
Current three-phase power factor correction (PFC) devices employ complex inverter circuits, which can be inefficient and costly to implement and maintain.
Innovation Solution
A three-phase AC to DC conversion device utilizing simple Boost-type circuits with forward and reverse diode connections to output capacitors, along with a control circuit and series inductance, to achieve power factor correction and efficient energy conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex three-phase inverter circuits are used for power factor correction, then power factor correction capability is achieved, but device complexity and cost increase
Solution Approach 1:
The three-phase PFC circuit is segmented into three independent single-phase Boost circuits, each handling one phase. This segmentation allows each circuit to be simpler while collectively achieving three-phase PFC functionality, directly resolving the contradiction between PFC capability and circuit complexity
Solution Approach 2:
Each Boost circuit serves multiple functions: power factor correction, voltage boosting, and energy storage. This multi-functionality eliminates the need for separate PFC and voltage regulation circuits, reducing overall device complexity while maintaining PFC capability
2Power
If complex inverter circuits are used, then power conversion is achieved, but energy conversion efficiency decreases
Solution Approach 1:
The Boost circuits operate in a self-regulating manner where the inductor current naturally follows the rectified voltage waveform, providing automatic power factor correction without complex control. This self-service operation reduces control losses and improves energy conversion efficiency
Solution Approach 2:
The six diodes ensure continuous current flow through the Boost circuits by directing current from any of the three phases to the output capacitors. This continuous operation eliminates discontinuous conduction losses and maintains high energy conversion efficiency
3Device complexity
If simple Boost circuits are used, then device simplicity is achieved, but ability to handle three-phase input may be insufficient
Solution Approach 1:
Three simple single-phase Boost circuits are merged into a unified three-phase PFC system. The circuits share common output capacitors and are interconnected through diodes, allowing simple individual circuits to collectively handle three-phase input effectively
Solution Approach 2:
The diodes serve as intermediaries that connect the three independent Boost circuits to the common output and to each other. These diodes enable the simple Boost circuits to interact and collectively process three-phase input without requiring complex coupling circuits
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 solution enables efficient and cost-effective power factor correction by simplifying the circuit design, improving energy conversion efficiency, and maintaining proportional voltage and current phases, thus addressing the inefficiencies of complex inverter-based systems.
Implementation Method 1
a first circuit of the Boost type... a fourth circuit of the Boost type
Implementation Method 2
via a first diode connected in the forward direction... via a second diode connected in the forward direction
Implementation Method 3
the outputs of said first, second and third Boost-type circuits being connected to a terminal of a first output capacitor
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
The invention relates to a device for converting electrical energy from a three-phase AC power supply to a DC output, comprising three input phases. Each input phase is connected, via forward-connected diodes (D1-D6), to the input of first Boost circuits (101, 103), and via reverse-connected diodes (D7-D12), to the input of second Boost circuits (104, 106), in circular permutation. The outputs of the first Boost circuits are connected to one terminal of a first output capacitor (110), and the outputs of the second Boost circuits are connected to one terminal of a second output capacitor (120), the other terminals of the output capacitors being connected together.