CAN-Synchronized Boost Converters for Balanced Parallel Startup
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Solution Overview
Problem
In power supply systems with multiple non-isolated boost converters, asynchronous startup leads to uneven voltage levels, circulating currents, and unbalanced load distribution, causing inrush currents, premature Overcurrent Protection (OCP) triggers, and stress on semiconductor components, reducing system reliability and increasing maintenance needs.
Innovation Solution
A synchronization mechanism using a Controller Area Network (CAN) bus assigns one converter as a master and triggers others as slaves, ensuring synchronized activation of MOSFETs within 100 microseconds, minimizing latency and stress, and using a memory to store conditions for safe startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple converters are powered on independently without synchronization, then each converter can operate autonomously, but uneven voltage levels and circulating currents occur leading to inrush currents and premature OCP triggers
Solution Approach 1:
A CAN bus is introduced as an intermediary communication medium between converters. The master converter transmits synchronization signals through the CAN bus to slave converters, coordinating their startup sequences without requiring direct hardware interconnections. This mediator enables coordinated operation while preserving the modular autonomous architecture of individual converters.
2Device complexity
If converters start without synchronization, then simpler control logic is used, but inrush currents cause stress on semiconductor components and increase maintenance needs
Solution Approach 1:
The master converter performs preliminary actions by transmitting readiness signals and synchronization commands to slave converters before actual power-on. Slave converters remain in a standby state, receiving and processing synchronization signals in advance, ensuring they activate simultaneously with the master converter. This preliminary coordination prevents inrush currents and component stress during startup.
3Device complexity
If no synchronization mechanism is implemented, then fewer communication components are needed, but load imbalances persist during transient conditions
Solution Approach 1:
The CAN bus enables feedback communication where slave converters acknowledge receipt of synchronization signals and report their operational status to the master converter. This feedback mechanism allows the master converter to monitor and adjust the synchronization process, ensuring balanced load distribution across all converters during transient conditions and steady-state operation.
Data Source
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AI summary
A power supply system 100 for synchronizing operation of plurality of converters 106 connected in parallel manner is disclosed. The power supply system 100 comprises a plurality of rectifiers 104 configured to convert an AC input into a regulated DC input voltage supplied to the converters 106. Each converter 106 is equipped with a MOSFET 202 and is connected to a CAN bus 204. A triggering unit 206 within the CAN bus 204 designates one converter 106 as the master, which transmits a synchronization signal to the slave converters to simultaneously turn ON all MOSFETs 202 during power-on. A memory 208 stores predefined threshold values of gate terminal voltage. The power supply system 100 ensures reliable start up by avoiding overcurrent trips, enabling effective load sharing, and minimizing semiconductor stress during power-on events.