Parallel Power Supply Current Sharing Across Different References
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Solution Overview
Problem
Existing power supply systems with parallel-connected power supplies face challenges in ensuring equal load distribution and balanced output currents due to differing electrical reference potentials, leading to asymmetrical currents and potential component stress, which can result in premature failure.
Innovation Solution
A power supply system with multiple power supply units connected in parallel, each with its own voltage regulator, utilizes a control unit to generate voltage setpoints referenced to a common electrical reference potential, and employs a second voltage regulator to correct output currents, minimizing differences between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power supplies are connected in parallel to increase output power, then the power supply capacity is improved, but the load current distribution becomes unbalanced causing one power supply to operate at high load continuously
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the output currents of both power supplies and adjusts their output voltages accordingly. The control unit generates control signals based on the detected current imbalance, creating a closed-loop system that automatically corrects load distribution issues and prevents one power supply from operating continuously at high load.
Solution Approach 2:
The patent dynamically changes the output voltage parameter of the power supplies based on their respective load conditions. By adjusting the voltage output of each power supply individually according to its current output, the system optimizes load distribution across the parallel-connected units, ensuring more equitable current sharing.
2Reliability
If power supplies are operated with sloping output characteristics to symmetrize load currents, then the load current balance is improved, but the output voltage becomes non-constant
Solution Approach 1:
The patent employs dynamic voltage adjustment where the output voltage of each power supply is continuously adapted based on real-time current measurements. Instead of using fixed sloping characteristics, the control unit dynamically modifies voltage parameters to achieve both current symmetry and voltage constancy, allowing the system to respond adaptively to changing load conditions.
Solution Approach 2:
The control unit uses feedback from current sensors to continuously monitor and adjust output voltages. This closed-loop control ensures that load current symmetry is maintained while simultaneously compensating for voltage variations, thereby achieving both objectives that the conventional sloping characteristic method cannot accomplish simultaneously.
3Adaptability or versatility
If different electrical reference potentials are used in parallel power supply units, then design flexibility is improved, but asymmetrical currents occur between the power supplies
Solution Approach 1:
The control unit implements feedback control that detects current imbalances caused by different reference potentials and generates compensating control signals. By continuously monitoring the actual current output of each power supply and adjusting their respective voltages, the system counteracts the asymmetrical effects of different reference potentials while maintaining design flexibility.
Solution Approach 2:
The patent dynamically adjusts voltage parameters to compensate for the effects of different reference potentials. By changing the voltage output of each power supply based on its reference potential difference, the system achieves current symmetry despite the design flexibility provided by different reference potentials.
Data Source
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AI summary
A power supply system (10) according to the invention comprises a first power supply unit (11), at least one second power supply unit (12), and a control and/or regulation unit (4), wherein the first power supply unit (11) and the at least one second power supply unit (12) are connected in parallel on the output side to jointly supply a load (3). The first power supply unit (11) is configured to provide a first output voltage (U1) and a first output current (11) on the output side and comprises a first voltage regulator (31) that regulates the first output voltage (U1) with respect to a first electrical reference potential (G1).The second power supply unit (12) is configured to provide a second output voltage (U2) and a second output current (I2) and includes a second voltage regulator (32) that regulates the second output voltage (U2) with respect to a second electrical reference potential (G2). The control unit (4) generates first voltage setpoints (USP1) for the first voltage regulator (31) and second voltage setpoints (USP2) for the second voltage regulator (32), wherein the first and second voltage setpoints (USP1, USP2) are each referenced to the first electrical reference potential (G1) and wherein the first electrical reference potential (G1) and the second electrical reference potential (G2) are different.The power supply system (10) is designed to at least minimize, and preferably reduce to zero, the difference between the first output current (I1) and the second output current (I2) caused by the different electrical reference potentials (G1, G2). This allows for a high degree of design flexibility, requiring less circuitry and control engineering effort for the power supply system (10), while ensuring an equal electrical load on the power supply units (11, 12).