Parallel Buck-Boost Converters Duty Cycle Control
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Solution Overview
Problem
Traditional power factor correcting converters face challenges with varying input power sources, leading to large voltage differences and uncontrolled return currents, which complicate current sensing and infrastructure sizing, and limit the adoption of power converter solutions due to increased costs and complexity.
Innovation Solution
A universal source parallel non-isolated buck-boost power factor correcting converter system that can handle high potentials and uncontrolled return currents, enabling input power sharing and operating in both buck and boost modes to accommodate different voltage levels, while providing redundant operation and efficient energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple power factor correcting converters are used to handle varied input power sources, then the system can accommodate different voltage levels and improve adaptability, but large voltage differences between converters expose computing systems to potential differences and make control difficult
Solution Approach 1:
The patent implements dynamic duty cycle adjustment where each converter's duty cycle is modified in real-time based on its input voltage level. Converters with higher input voltages receive extended duty cycles while those with lower voltages receive reduced duty cycles, dynamically balancing the output voltages and eliminating potential differences between parallel converters.
Solution Approach 2:
The system changes the operational parameters (duty cycles) of each converter based on their specific input conditions. By monitoring input voltage levels and adjusting duty cycles accordingly, the system transforms the fixed-parameter operation into variable-parameter operation, allowing each converter to adapt to its input source while maintaining synchronized output.
2Adaptability or versatility
If traditional power factor correcting converters are used with separate inputs, then they can handle different power sources, but they cannot control return current which complicates current sensing and makes infrastructure sizing difficult
Solution Approach 1:
The patent segments the return current path by introducing separate return path switches for each converter. This segmentation allows independent control and measurement of return currents from each converter, transforming the uncontrolled shared return path into controlled individual paths that can be sensed and managed separately.
Solution Approach 2:
The controller acts as an intermediary that coordinates the operation of multiple converters and their return path switches. It monitors input voltages, calculates appropriate duty cycles, and controls the switching sequences to ensure proper current flow and return path management, simplifying the overall current sensing and control architecture.
3Ease of manufacture
If non-isolated converters are used to reduce cost and size, then efficiency improves and physical size reduces, but they cannot handle uncontrolled return currents and require elaborate control
Solution Approach 1:
The patent creates a universal converter design that can handle both isolated and non-isolated voltage and phase relationships between inputs. The same converter topology and control algorithm work regardless of whether inputs are isolated or non-isolated, eliminating the need for separate designs and reducing overall system complexity despite the versatility gained.
Data Source
AI summary
An example device in accordance with an aspect of the present disclosure includes a first converter to selectively convert a first input signal to a first output signal, and a second converter to selectively convert a second input signal to a second output signal. A controller is to control switches of the first and second converters based on the input signals and output signals, and based on operating the first and second converters exclusively with respect to each other such that a total of first and second duty cycles does not exceed one.