Power Conversion Apparatus Series-Parallel Topology
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Solution Overview
Problem
Existing power conversion technologies face challenges with high volume and stress on switching devices, large magnetic components, and complex control systems, which affect efficiency and power density, especially in medium and high-power applications.
Innovation Solution
A power conversion apparatus comprising a boost unit and multiple power conversion units, where input ends are connected in series and output ends in parallel, reducing voltage and current stress on switching devices, and incorporating non-isolated and isolated conversion subunits to achieve automatic current sharing and simplified control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single power converter adopts a two-stage structure with PFC unit and DC-DC conversion unit, then the voltage can be pre-regulated and converted to required output voltage, but the stress of switching device is high and the volume of magnetic device is large
Solution Approach 1:
The power conversion apparatus is divided into multiple power conversion units (at least two) that are connected in parallel, with each unit having its own switching device and magnetic components. This segmentation distributes the power conversion task across multiple smaller units, reducing the volume of magnetic devices in each unit while maintaining the total power conversion capability.
Solution Approach 2:
Multiple power conversion units are merged in parallel connection, where the input ends are connected to the same input voltage and output ends are connected to the same output. This merging allows the system to achieve high power conversion capability while each individual unit operates at lower stress levels with smaller magnetic components.
2Reliability
If multiphase parallel connection is realized on PFC unit or DC-DC unit, then the stress of device and volume of magnetic part are reduced, but the control complexity increases due to requirement of additional current-sharing control
Solution Approach 1:
The power conversion units operate autonomously with self-service current sharing capability. Each unit independently controls its own switching device and magnetic components, and the current distribution among units is automatically balanced through the circuit topology and control strategy, eliminating the need for complex additional current-sharing control mechanisms.
Solution Approach 2:
The control system incorporates feedback mechanisms that monitor the operating status of each power conversion unit and automatically adjust the switching signals to achieve balanced current distribution. This feedback-based control simplifies the overall system by using standard control techniques rather than requiring complex dedicated current-sharing algorithms.
3Loss of energy
If interleaved control is used in multiphase parallel connection, then efficiency and heat dissipation are improved, but input and output current ripples are reduced only to some extent
Solution Approach 1:
The power conversion units employ periodic switching actions with different phase shifts. Each unit switches at a specific phase angle, creating periodic current waveforms that complement each other. This periodic action with proper phase distribution significantly reduces input and output current ripples while maintaining high efficiency and improved heat dissipation characteristics.
Data Source
AI summary
The present disclosure discloses a power conversion apparatus and a method for configuring the same. The power conversion apparatus includes a boost unit and at least two power conversion units; each of the power conversion units has two input ends; an input end of the boost unit is connected with one end of an alternating-current power supply, and an output end of the boost unit is connected with one input end of a first power conversion unit of the plurality of power conversion units; one input end of a last power conversion unit of the plurality of power conversion units is connected with the other end of the alternating-current power supply; and the input ends of the plurality of power conversion units are connected in series, and the output ends of the plurality of power conversion units are connected in parallel.