Power Converter with Separate Buck and Boost Circuits
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Solution Overview
Problem
Conventional buck-boost converters have limitations in efficiency and operational range, as they share components for buck and boost functionalities, leading to restricted applications and narrow input/output voltage ranges.
Innovation Solution
A power converter with separate and independently controllable buck and boost conversion circuits, utilizing a control unit that samples input and output voltages and currents to adjust switching frequencies and duty cycles, allowing operation in both buck and boost modes over a wide range of voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional buck-boost converters share components for buck and boost functionalities, then device complexity is reduced, but efficiency and operational range are limited
Solution Approach 1:
The power converter is divided into separate buck conversion circuit and boost conversion circuit, each with independent switching devices. The buck circuit includes switching devices Q1-Q4 while the boost circuit includes switching devices Q5-Q8, allowing independent control and optimization of each conversion mode, thereby expanding operational range without compromising efficiency
Solution Approach 2:
The power converter is designed to perform multiple functions through separate circuits - it can operate in buck mode when input voltage exceeds output voltage, in boost mode when input voltage is lower than output voltage, and in direct connection mode when voltages are equal, making it universally applicable across wide voltage ranges
2Ease of operation
If buck and boost functionalities share switching devices, then device complexity is reduced, but control flexibility is limited
Solution Approach 1:
The switching devices are segmented into two independent groups: Q1-Q4 for buck conversion and Q5-Q8 for boost conversion. Each group can be controlled independently by the control unit, enabling flexible switching between modes and independent optimization of duty cycles and switching frequencies for each circuit
Solution Approach 2:
The control unit dynamically adjusts the operation mode by comparing input and output voltages and accordingly activating different switching device groups. The system can transition between buck mode, boost mode, and direct connection mode based on real-time voltage conditions, providing dynamic control flexibility
3Loss of energy
If conventional buck-boost converters use shared components, then manufacturing is simpler, but efficiency over wide voltage range is reduced
Solution Approach 1:
By segmenting the conversion circuits into separate buck and boost paths with independent switching devices, each circuit can be optimized for its specific conversion mode, minimizing energy losses associated with component sharing and enabling high efficiency across both buck and boost operations
Solution Approach 2:
The control unit independently adjusts switching frequencies and duty cycles for each circuit based on operating conditions. When operating in buck mode, it optimizes parameters for the buck circuit; when in boost mode, it optimizes parameters for the boost circuit, thereby maintaining high conversion efficiency across wide voltage ranges
Data Source
AI summary
An apparatus (100) includes a buck and boost conversion circuit (110), and a control unit (120, 200) for controlling operations of the buck and boost converter. The buck and boost converter includes a buck conversion circuit having a first set of switches (SW3, SW4), and a boost conversion circuit having a second set of switches (SW5, SW6). The buck conversion circuit and the boost conversion circuit may be controlled independently from each other. The control unit is configured to control delivery of power from the power converter to a load (20) via the buck conversion circuit in a buck conversion mode by controlling switching operations of the first set of switches, and to control the delivery of the power from the power converter to the load via the boost conversion circuit in a boost conversion mode by controlling switching operations of the second set of switches.