Digital Current-Sharing Loop Design for PSU Voltage Regulation
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Solution Overview
Problem
In information handling systems (IHS) with multiple power supply units (PSUs) in parallel operation, the output voltage tends to lose regulation during dynamic load transients due to current sharing issues, leading to instability, and attempts to mitigate this with increased interconnection impedance result in additional power losses.
Innovation Solution
Implementing a master-slave current sharing control mechanism where each PSU includes an internal current sensor and a master control unit (MCU) that delays and matches the internal current signal with the shared current signal, allowing the MCU to control the output amplifier to maintain local DC power in proportion to contributions from other PSUs, thereby stabilizing the voltage during load transients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple PSUs are placed in parallel operation to achieve power redundancy, then power reliability is improved, but output voltage regulation is lost during dynamic load transients
Solution Approach 1:
The patent implements a feedback mechanism where each PSU monitors the shared current signal and adjusts its output accordingly. The master control unit continuously compares the shared current signal with the local current signal and modifies the output amplifier control to maintain proper current sharing and voltage regulation during load transients.
Solution Approach 2:
The patent changes the timing parameter of the local current signal by introducing a delay that matches the delay in the shared current signal. This parameter adjustment synchronizes the response of all PSUs, preventing voltage drift and maintaining regulation during dynamic load conditions.
2Stability of the object's composition
If increased interconnection impedance is used to mitigate current sharing problems, then current sharing stability is improved, but power losses increase
Solution Approach 1:
The patent introduces an intermediary control mechanism through the master control unit that mediates between the shared current signal and the local output amplifiers. This electronic control intermediary replaces the need for increased physical impedance, achieving current sharing stability without the penalty of additional power losses.
3Ease of operation
If shared current signal is used for master-slave current sharing control, then current sharing is achieved, but signal delay causes instability in dynamic response to load transients
Solution Approach 1:
The patent applies preliminary action by pre-delaying the local current signal to match the expected delay in the shared current signal path. This anticipatory timing adjustment ensures that both signals arrive at the control unit simultaneously, maintaining stability during dynamic load responses.
Data Source
AI summary
Power supply units (PSU) provide for digital current-sharing loop control to ensure output voltage regulation during dynamic load transients by (i) delaying an internal current signal to match a delay in a shared current signal, and (ii) controlling the output amplifier based on the shared current signal and the delayed local current signal to maintain the respective local DC electrical power in proportion to contributions by other ones of the more than one PSU to the shared DC electrical power and thereby avoid instability in dynamic response to a load transient induced by the power consuming component.