Multi-Phase Power Conversion Control for Stable Voltage Gain Switching
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Solution Overview
Problem
Conventional power conversion devices using single three-phase resonant circuits fail to achieve the desired gain between input and output voltages due to varying voltage and current requirements, leading to overshoot and undershoot when switched to different phases.
Innovation Solution
A multi-phase circuit control method involving a first and second phase circuit, each with primary and rectifier side circuits, uses a controller to generate control signals for converting input voltage into required output voltage, adjusting duty cycles to output two-phase, single-phase, or three-phase voltages based on detected output voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single three-phase resonant circuit is used for power conversion, then the device structure is simple, but the gain between input voltage and output voltage cannot reach the expected gain and cannot cover the expected operating range
Solution Approach 1:
The power conversion device is divided into multiple independent phase circuits (first phase circuit, second phase circuit, third phase circuit), each capable of operating independently. This segmentation allows the system to provide different voltage gains by selecting different phase combinations, resolving the contradiction between simple structure and wide adaptability range.
Solution Approach 2:
Each phase circuit is designed with universal functionality to handle different voltage conversion requirements. The circuits can be individually or collectively activated based on the required output voltage and current ranges, making the device adaptable to multiple operating conditions while maintaining a relatively simple overall structure.
2Adaptability or versatility
If a three-phase resonant circuit is directly switched to two-phase or single-phase output, then the circuit can adapt to different voltage ranges, but the output voltage and output current will overshoot and undershoot
Solution Approach 1:
The controller dynamically adjusts the duty cycles of control signals for each phase circuit based on real-time output voltage and current conditions. This dynamic control prevents abrupt transitions between operating modes, eliminating overshoot and undershoot while maintaining adaptability to different voltage ranges.
Solution Approach 2:
The controller receives feedback from output voltage and current detectors and adjusts the control signals accordingly. This closed-loop feedback mechanism ensures stable output transitions when switching between three-phase, two-phase, or single-phase operation, preventing instability while maintaining voltage range adaptability.
3Adaptability or versatility
If different duty cycles are used for different phase circuits, then the output voltage requirements can be met, but the circuit control complexity increases
Solution Approach 1:
The controller changes the duty cycle parameters of control signals for each phase circuit based on the detected output voltage level. By systematically adjusting these parameters according to predefined voltage thresholds, the system meets diverse output requirements while keeping control logic manageable through parameterized control rather than complex circuit design.
Data Source
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AI summary
A multi-phase circuit control method includes following steps: generating a first control signal and a second control signal to a first phase circuit respectively by a controller; generating a third control signal and a fourth control signal to a second phase circuit respectively by controller; outputting a two-phase voltage to a output terminal of a power conversion device by first phase circuit and second phase circuit; changing a duty cycle of third control signal to turn off a first switch of a primary side circuit and a rectifier side circuit of second phase circuit by controller when controller is configured to detect that output voltage is lower than a first preset voltage; changing a duty cycle of fourth control signal to conduct a second switch of a primary side circuit and a rectifier side circuit of second phase circuit; and outputting a single-phase voltage to output terminal.