Parallel Power Supply Synchronization via Wired-OR Bus
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Solution Overview
Problem
Power supply systems with multiple parallel-connected apparatuses face noise generation and signal distortion due to high-frequency synchronization signals, requiring separate master and slave configurations and noisy transmission lines.
Innovation Solution
A power supply system with a synchronization pulse bus line connecting synchronization pulse generators in an open collector or open drain structure, allowing synchronized operation without distinguishing between master and slave, and generating synchronization pulses with a frequency lower than or equal to the switching frequency to reduce noise and signal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency synchronization signals are used to synchronize switching operations of parallel power supply apparatuses, then synchronization precision is improved, but noise generation and signal distortion increase due to transmission line effects
Solution Approach 1:
Instead of using a master apparatus to generate and transmit synchronization signals to slave apparatuses (conventional approach), each apparatus independently generates its own synchronization signal and simultaneously receives signals from others. This inverted approach eliminates the need for noisy transmission lines while maintaining synchronization precision through the wired-OR connection mechanism.
Solution Approach 2:
The wired-OR connection structure acts as an intermediary that allows multiple synchronization signal sources to coexist without direct master-slave transmission. The bus line with pull-up resistors mediates between multiple generators, enabling noise-free synchronization by allowing any apparatus to assert its signal without being a slave to another.
2Ease of operation
If separate master and slave power supply apparatuses are provided for synchronization, then control hierarchy is established, but device complexity increases and noise from transmission lines cannot be eliminated
Solution Approach 1:
Each power supply apparatus is designed with universal functionality to both generate and receive synchronization signals simultaneously. This eliminates the need for separate master and slave configurations, reducing system complexity while maintaining operational control through the ability of any apparatus to become a signal source when needed.
Solution Approach 2:
Each apparatus serves itself by independently generating synchronization signals based on its own switching cycle, rather than relying on external master control. This self-service approach simplifies the system by eliminating dedicated master apparatuses while maintaining synchronization through the wired-OR bus connection.
3Measurement precision
If synchronization signal frequency is increased to improve synchronization accuracy, then synchronization precision is improved, but signal distortion and noise reception due to transmission line effects worsen
Solution Approach 1:
The patent extracts the problematic transmission line from the synchronization system by having each apparatus generate its own signal locally. The wired-OR connection allows direct assertion of synchronization signals without requiring long transmission lines, thereby eliminating signal distortion and noise reception issues while maintaining high synchronization accuracy.
Data Source
AI summary
A power supply system includes a plurality of power supply apparatuses whose inputs and outputs are respectively connected in parallel with one another. The output of each of the plurality of power supply apparatuses is wired-OR connected to a synchronization pulse bus line in an open collector structure or an open drain structure. The plurality of power supply apparatuses each include a synchronization pulse generator generating a synchronization pulse for synchronization of a switching cycle, and a switching control circuit, connected to the synchronization pulse bus line, performing switching control of a switch device in synchronization with a signal of the synchronization pulse bus line. There is no distinction between a master power supply apparatus and a slave power supply apparatus in the plurality of power supply apparatuses. Further, generation of noise due to a transmission line for a synchronization signal is avoided.