Interleaved Parallel Power Converter for ZVS and Low Output Ripple
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Solution Overview
Problem
High-gain power converters using cascade connections face issues with increased ripple in output voltage and the need for larger output capacitors, which can lead to higher losses and inefficiencies due to hard switching and phase differences in switching power stage circuits.
Innovation Solution
Implementing an interleaved parallel connection of multiple switching power stage circuits with a phase-shifted control operation and adaptive dead time to achieve zero-voltage-switching (ZVS) and reduce ripple, thereby minimizing the required output capacitor size and switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cascade connection is used to achieve high gain, then power conversion gain is improved, but output voltage ripple increases and output capacitor size must be increased
Solution Approach 1:
The power converter is divided into multiple parallel switching power stage circuits (first, second, and third circuits) with different duty cycles. Each circuit segment handles a portion of the power conversion, allowing the system to achieve high gain through coordinated operation of segments rather than a single cascade stage, thereby reducing output voltage ripple.
Solution Approach 2:
Multiple switching power stage circuits are merged in parallel configuration with their output terminals connected together. The circuits operate with phase-shifted duty cycles to combine their output contributions, achieving high power conversion gain while the combined operation smooths out individual circuit ripples, reducing overall output voltage ripple.
2Stability of the object's composition
If larger output capacitor is used to reduce ripple, then output voltage stability is improved, but device complexity and losses increase
Solution Approach 1:
The output filtering function is segmented across multiple parallel power stage circuits rather than relying on a single large capacitor. Each circuit contributes to ripple reduction through its synchronized operation, allowing the use of smaller individual capacitors that collectively provide the required voltage stability.
Solution Approach 2:
The switching power stage circuits operate with periodic, phase-shifted duty cycles. This periodic switching pattern ensures that when one circuit is switching and generating ripple, other circuits are in different phases, creating a combined output with reduced ripple amplitude, thereby maintaining voltage stability with smaller capacitance.
3Device complexity
If hard switching is used in parallel circuits, then circuit simplicity is maintained, but switching losses increase due to phase differences
Solution Approach 1:
The control circuit预先 adjusts the duty cycles of the parallel switching power stage circuits to create phase differences between them. This preliminary timing adjustment ensures that switching events are staggered, allowing one circuit to complete its switching transition before another begins, thereby reducing simultaneous switching conflicts and associated losses while maintaining circuit simplicity.
Data Source
AI summary
A power converter can include: N switching power stage circuits, where output terminals of the N switching power stage circuits are connected in parallel, and N is a positive integer; an energy storage element coupled between an input terminal and the output terminal of the power converter, where the energy storage element is configured to periodically store energy for delivery to the output terminal of the power converter; and where after a main transistor of an M-th switching power stage circuit is turned off, a main transistor of the (M+1)-th switching power stage circuit is turned on, in order to realize zero-voltage-switching (ZVS) of the main transistor of (M+1)-th switching power stage circuit, where M is a positive integer less than N.