Synchronous Harmonic Converter for Single-Stage Power Factor Correction
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Solution Overview
Problem
Existing single stage power factor corrected converters face challenges in reducing switching current and improving voltage regulation, particularly in low noise applications, with architectures like flyback and Ćuk converters limited by large magnetic and switch currents and output voltage ripple.
Innovation Solution
A single stage bidirectional power factor corrected converter is implemented using a power factor correction stage merged with a regulated resonant converter, employing synchronous average harmonic current control to harmonically filter and synchronize primary and secondary bridges, reducing locally recirculating bridge current and transformer ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate circuits are used for power factor correction and harmonic filtering, then each function can be optimized independently, but the overall device complexity and cost increase
Solution Approach 1:
The patent combines power factor correction and harmonic filtering functions into a single integrated circuit. The synchronous converter simultaneously performs both functions by processing the rectified voltage and current signals through unified control logic, eliminating the need for separate correction and filtering circuits while maintaining optimal performance of both functions.
Solution Approach 2:
The synchronous converter is designed as a multi-functional device that performs power factor correction, harmonic filtering, and reactive power compensation all through a single circuit architecture. This universal approach allows one device to replace multiple specialized devices, reducing overall system complexity.
2Adaptability or versatility
If traditional separate devices are used for power factor correction and harmonic filtering, then installation flexibility is maintained, but space requirements and cost increase
Solution Approach 1:
By merging power factor correction and harmonic filtering into one integrated synchronous converter, the patent reduces the total volume occupied by equipment. Instead of requiring separate devices installed in different locations, the unified design consolidates all functions into a single compact unit that can be installed in one location.
3Device complexity
If asynchronous converters are used for power factor correction, then simplicity is maintained, but harmonic distortion remains uncorrected and overall efficiency decreases
Solution Approach 1:
The patent converts the previously harmful harmonic distortions into beneficial effects by using them as part of the control signal for the synchronous converter. The converter processes both the fundamental frequency and harmonic components, transforming what was previously waste energy into useful information for achieving unity power factor and eliminating harmonics simultaneously.
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
This approach achieves efficient voltage regulation and reduced switching current, eliminating the need for additional power stages, thereby improving efficiency and reducing noise in low noise applications.
Implementation Method 1
A synchronous converter circuit corrects the power factor of a full wave rectified voltage waveform by an amount equal to the reactive power consumed by a filter
Implementation Method 2
The converter eliminates the need for separate power factor correcting and harmonic filtering circuits
Data Source
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AI summary
A synchronous average harmonic current controller for a line connected bidirectional resonant power converter results in a harmonic voltage gain closely related to the commanded bridge duty cycles. A primary bridge has its duty cycle set to achieve controlled line power transfer and voltage regulation of a primary bus energy storage capacitor. A secondary bridge circuit has its duty cycle set to achieve voltage regulation of secondary bus energy storage capacitor. A first embodiment uses the independent energy storage elements to achieve power factor correction and low noise regulation using a single stage. A second embodiment uses feedforward duty cycle control to achieve isolated voltage regulation using the well-defined voltage gain resulting from the synchronous average harmonic current controller.