Parallel PCS Synchronization Bus for Stable PWM Phase Control
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Solution Overview
Problem
When multiple power conversion systems (PCSs) are connected in parallel, phase and pulse asynchronization between the PWM output signal of individual PCSs and the AC mains power signal can cause circular current, oscillation, and control instability in the system.
Innovation Solution
A phase/pulse synchronization control method is implemented in a power conversion system parallel architecture, where the PWM signals of multiple PCSs are synchronized with the AC mains power signal using a synchronization signal bus. The PCS controller determines the master control based on the earliest synchronization signal transmission, using this signal as the system synchronization signal for other PCSs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PCSs are connected in parallel to increase system flexibility and capacity, then the adaptability and power output are improved, but phase and pulse asynchronization occurs causing circular current, oscillation, and control instability
Solution Approach 1:
The patent introduces a synchronization signal bus as an intermediary communication channel between multiple PCS controllers. This bus transmits synchronization signals that coordinate the PWM output phases and pulses of all PCSs, ensuring they operate in unison. The intermediary synchronization mechanism resolves the contradiction by enabling parallel operation (improving adaptability) while maintaining phase coherence (ensuring reliability).
Solution Approach 2:
The patent implements a feedback mechanism where each PCS controller monitors the synchronization signal bus and adjusts its PWM generation accordingly. The controllers receive feedback about the system's synchronization state and modify their operation to maintain phase alignment. This feedback loop prevents circular current and oscillation by continuously correcting phase deviations, thus maintaining system stability while allowing parallel expansion.
2Device complexity
If each PCS operates independently with its own PWM signal generation, then the device complexity is reduced, but signal output error and control instability occur
Solution Approach 1:
The patent merges the synchronization functions of multiple independent PCS controllers by introducing a common synchronization signal bus. Instead of each controller operating completely independently, they are combined through the shared communication channel that transmits phase and pulse synchronization signals. This merging approach maintains the simplicity of individual PCS units while achieving coordinated operation, thus preserving signal precision without significantly increasing overall system complexity.
Data Source
AI summary
The application discloses a power conversion system (PCS) parallel architecture and a synchronous control method. Among a plurality of corresponding PCS controllers of the PCS parallel architecture, when a target PCS controller is the first to issue a synchronization signal on a synchronization signal bus, the target PCS controller obtains control authority, the synchronization signal issued by the target PCS controller is taken as a system synchronization signal, and other PCS controllers that did not obtain control authority refer to the system synchronization signal for synchronizing with the system synchronization signal.