Partial Power Switching Converter for Wide Output Voltage Control
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Solution Overview
Problem
Existing partial power converters face challenges in efficiently regulating a wide output voltage range while minimizing power losses and transistor breakdown voltage requirements, particularly in battery charger applications.
Innovation Solution
A power conversion circuit with a first converter stage generating a DC bus voltage and a second converter stage comprising a main branch and a partial power branch, where the main branch provides a fixed conversion ratio and the partial power branch adjusts the output voltage, controlled by a controller to set the desired output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wide output voltage range is required for battery charging, then the converter must handle voltages from 250V to 450V, but this requires transistors with high breakdown voltage (150V or more) which increases device complexity and cost
Solution Approach 1:
The patent divides the power conversion function into two separate branches: a main branch with fixed conversion ratio and a partial power branch with adjustable conversion ratio. This segmentation allows each branch to be optimized independently, with the partial power branch handling only the voltage adjustment portion (processing a small fraction of total power) while the main branch handles the bulk power transfer, thereby reducing the voltage stress requirements on individual transistors
Solution Approach 2:
The patent applies partial power processing by having the partial power branch process only a small fraction of the total output power. The partial power branch contains the regulator capable of regulating output voltage across the wide range (250V to 450V), while the main branch provides fixed ratio conversion. This allows the voltage regulation function to be achieved with lower voltage transistors in the partial power branch, reducing overall device complexity
2Loss of energy
If output voltage regulation is performed in a partial power branch, then efficiency is improved and power losses are reduced, but the converter requires a more complex two-branch architecture
Solution Approach 1:
The converter is segmented into a main branch for bulk power transfer with fixed conversion ratio and a partial power branch for voltage regulation. This segmentation concentrates the regulation function in one branch, minimizing the power processed through regulating elements and thereby reducing associated losses while maintaining a manageable architectural complexity
Solution Approach 2:
The patent changes the operating parameters of the two branches differently: the main branch operates at a fixed conversion ratio optimized for bulk power transfer, while the partial power branch dynamically adjusts its conversion ratio to regulate the output voltage. This parameter differentiation allows efficient power conversion while maintaining architectural simplicity
Data Source
AI summary
A power conversion circuit is described herein. In accordance with one embodiment, the circuit includes a first converter stage configured to provide a DC bus voltage and a second converter stage configured to receive the DC bus voltage and to generate an output voltage therefrom. The second converter stage includes at least a main branch and a partial power branch, wherein the main branch is configured to provide, at its output, a first voltage from the DC bus voltage based on a fixed conversion ratio and the partial power branch is configured to provide, at its output, an adjustable second voltage from the DC bus voltage. The outputs of the main branch and the partial power branch are connected in series to provide the output voltage. The circuit further includes a controller configured to control, in order to set the output voltage, the first converter stage to adjust the DC bus voltage and to control the partial power branch to adjust the second voltage.