Parallel Power Supply Ripple Reduction via Feedback Control
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Solution Overview
Problem
Conventional power supply systems experience significant current ripple when multiple power supplies are connected in parallel, especially when supplied with different input frequencies or phase angles, leading to inefficient load current sharing.
Innovation Solution
A DC power supply system with multiple power supply units connected in parallel, where a current feedback signal and a current reference signal are combined to produce a current error signal that adjusts the voltage control loop, using a low pass filter to average the current reference signal and compare it with real-time output current to generate an error signal, which is fed back to the voltage control loop to reduce line ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple power supply units are connected in parallel to share load current, then the power supply capacity and reliability are improved, but the current ripple increases when supplied with different input frequencies or phases
Solution Approach 1:
The patent implements a feedback mechanism where the output current of each power supply unit is sensed and fed back to the control circuit. The control circuit adjusts the duty cycle of the PWM signal based on the feedback signal to maintain equal current sharing among parallel power supply units, thereby reducing current ripple while preserving the increased power supply capacity.
Solution Approach 2:
The patent changes the operating parameters of the power supply units by adjusting the duty cycle of the PWM signal dynamically. When power supply units are supplied with different input frequencies or phases, the control circuit modifies the duty cycle parameter to compensate for current imbalances and reduce the harmful current ripple effect.
2Adaptability or versatility
If multiple power supply units operate with different input frequencies or phases, then the system adaptability is improved, but the current sharing precision deteriorates
Solution Approach 1:
The control circuit continuously monitors the output current of each power supply unit through feedback sensing and dynamically adjusts the duty cycle to maintain precise current sharing. This feedback mechanism enables the system to adapt to different input frequencies and phases while preserving current sharing precision through real-time correction.
Solution Approach 2:
The patent employs dynamic adjustment of the duty cycle parameter in response to varying input conditions. The control circuit adapts the operating parameters in real-time based on the actual current sharing status, allowing the system to maintain precision across different operational scenarios including different input frequencies and phases.
Data Source
AI summary
In the parallel operation of power supply units, a high line ripple current may be observed in output when the power supply units (PSUs) are supplied with different inputs. For example, a high line ripple current may be observed when PSUs were supplied with different line frequency inputs and/or when PSUs were supplied with different phase angle input lines. A low pass filter is in a control loop which is capable of filtering the line frequency to get an average current reference signal. The average current reference signal is compared with the real time output current to generate an error signal. This error signal is fed back to a voltage control loop to adjust the output in order to compensate the line ripple.