Single-Stage Isolated AC-DC Converter With Integrated Power Factor Correction
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Solution Overview
Problem
Existing power source designs for high-power electrical equipment, such as electric vehicles, require a two-stage structure with a power factor correction module that increases the volume and cost due to the need for higher filter inductors and larger voltage stabilizing capacitors, leading to harmonic pollution in the power grid current.
Innovation Solution
A single-stage three-phase isolated AC-DC converter circuit with a power factor correction function, comprising a primary-side AC-DC converter, a transformer, and a secondary-side AC-DC converter, where the controller adjusts duty ratios and phase differences of power switches to correct the power factor, reducing the capacity and volume of filter inductors and capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-stage structure with power factor correction module is used, then power factor correction function is achieved, but the volume and cost increase due to larger filter inductors and capacitors
Solution Approach 1:
The patent combines the power factor correction function with the AC-DC conversion function into a single integrated circuit stage. The AC input is directly converted to DC output while simultaneously achieving power factor correction, eliminating the need for separate power factor correction modules and their associated large filter inductors and capacitors.
Solution Approach 2:
The AC-DC converter circuit performs multiple functions simultaneously: it converts AC to DC, corrects power factor, and provides isolation through the transformer. This multi-functional design eliminates the need for dedicated power factor correction hardware, reducing overall circuit volume.
2Volume of stationary object
If a single-stage AC-DC converter is used, then the volume and cost are reduced, but the power factor correction capability must be integrated
Solution Approach 1:
The AC-DC converter circuit performs multiple functions simultaneously: it converts AC to DC, corrects power factor, and provides isolation through the transformer. This multi-functional design eliminates the need for dedicated power factor correction hardware, reducing overall circuit volume.
Solution Approach 2:
The patent employs control circuits that monitor the AC input and DC output parameters in real-time, adjusting the switching duty cycles of the power devices to maintain optimal power factor correction while performing AC-DC conversion. This feedback control enables the single-stage converter to achieve both functions effectively.
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 convenient power factor correction, minimizing power grid current pollution and reducing the size and cost of the charging source module by integrating power factor correction within a single-stage AC-DC converter circuit.
Implementation Method 1
a primary-side AC-DC converter, a transformer, a secondary-side AC-DC converter... the primary-side winding of the transformer is connected to a DC output side of the primary-side AC-DC converter... and a secondary-side winding of the transformer is connected to an AC input side of the secondary-side AC-DC converter
Data Source
AI summary
A single-stage AC-DC converter circuit with a power factor correction function. The single-stage AC-DC converter circuit comprises a primary-side AC-DC converter, a transformer, a secondary-side AC-DC converter and a controller which are connected to each other. The primary-side AC-DC converter is configured to convert an AC power source into DC. The secondary-side AC-DC converter is configured to convert electrical energy into DC and supply power to a load. The controller is configured to control duty ratios of power switches in the primary-side and secondary-side AC-DC converters, and a phase difference between control signals for the power switches, and finally control the amount of electrical energy transfer and correct a power factor. The single-stage AC-DC converter circuit of the present invention reduces the capacity and volume of a filter inductor and a voltage stabilizing capacitor, and has the advantages of simple circuit and low cost.