Three-Phase PFC Converter Topology for Leakage Current Elimination
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Solution Overview
Problem
Conventional three-phase PFC rectifiers with galvanic isolation are bulky and heavy due to the use of transformers, inductors, and DC link capacitors, while non-isolated converters suffer from undesired leakage currents caused by varying common mode voltages.
Innovation Solution
A single-stage, non-isolated three-phase PFC converter design utilizing a switching circuit, resonant circuit, autotransformer, and rectifier circuit, which generates an alternating voltage based on input voltages to control power factor and waveform, without galvanic isolation, reducing size and weight by using an autotransformer with a single winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic isolation is implemented using transformers, inductors, and DC link capacitors, then safety and electrical isolation are improved, but size and weight increase significantly
Solution Approach 1:
The patent removes the galvanic isolation stage (transformer) from the conventional two-stage PFC rectifier architecture, creating a single-stage non-isolated converter. This extraction eliminates the bulky transformer, inductors, and DC link capacitor while maintaining the essential power factor correction function through direct coupling of the switching circuit to the output.
Solution Approach 2:
The patent merges the rectification and power factor correction functions into a single integrated stage, eliminating the need for separate isolation and rectification stages. The switching circuit directly processes the three-phase input to produce the output voltage, combining multiple functions into one compact architecture.
2Reliability
If galvanic isolation is implemented using transformers, inductors, and DC link capacitors, then safety and electrical isolation are improved, but device volume increases significantly
Solution Approach 1:
The patent removes the galvanic isolation stage (transformer) from the conventional two-stage PFC rectifier architecture, creating a single-stage non-isolated converter. This extraction eliminates the bulky transformer, inductors, and DC link capacitor while maintaining the essential power factor correction function through direct coupling of the switching circuit to the output.
Solution Approach 2:
The patent merges the rectification and power factor correction functions into a single integrated stage, eliminating the need for separate isolation and rectification stages. The switching circuit directly processes the three-phase input to produce the output voltage, combining multiple functions into one compact architecture.
3Weight of stationary object
If non-isolated converter design is used to reduce size and weight, then component count and volume are reduced, but leakage currents increase due to varying common mode voltage
Solution Approach 1:
The patent introduces a resonant circuit as an intermediary between the switching circuit and the output. This resonant circuit acts as a mediator that processes the voltage transitions and eliminates the varying common mode voltage that causes leakage currents, while maintaining the compact non-isolated architecture.
4Reliability
If two-stage isolated architecture is used, then galvanic isolation is achieved, but device complexity increases
Solution Approach 1:
The patent merges the rectification and power factor correction functions into a single integrated stage, eliminating the need for separate isolation and rectification stages. The switching circuit directly processes the three-phase input to produce the output voltage, combining multiple functions into one compact architecture.
Solution Approach 2:
The patent removes the galvanic isolation stage (transformer) from the conventional two-stage PFC rectifier architecture, creating a single-stage non-isolated converter. This extraction eliminates the bulky transformer, inductors, and DC link capacitor while maintaining the essential power factor correction function through direct coupling of the switching circuit to the output.
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 design achieves reduced size, weight, and resource consumption while eliminating leakage currents, maintaining efficient power factor correction and voltage control.
Implementation Method 1
a resonant circuit coupled to a first output node of the switching circuit
Implementation Method 2
an autotransformer circuit coupled between the switching circuit and the rectifier circuit
Data Source
AI summary
A power converter and a method are disclosed. The power converter includes an input to receive three alternating input voltages; a switching circuit coupled to the input and comprising a three-phase half-bridge; an autotransformer circuit; and a rectifier circuit. The autotransformer circuit is coupled between the switching circuit and the rectifier circuit, and the rectifier circuit is coupled between the autotransformer circuit and an output of the power converter.