Active Current Limiting Circuit for ATS Inrush Current Control
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Solution Overview
Problem
Conventional methods for reducing inrush current in ATS power supplies, such as increasing bulk capacitor capacity or using resistive passive current limiting circuits, result in increased cost, power loss, and inflexible control, while passive circuits also lead to significant volume and power loss.
Innovation Solution
An active current limiting circuit with multiple current limiting switches that are controlled based on current sampling signals and voltage comparisons, reducing inrush current, lowering power consumption, and enabling flexible control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a resistive passive current limiting circuit is used to reduce inrush current, then inrush current is limited, but power loss increases significantly and volume increases
Solution Approach 1:
The patent replaces the resistive passive current limiting circuit with an active current limiting circuit that uses controllable switches (such as MOSFETs or IGBTs) to limit inrush current. This substitution allows for dynamic control of current limiting rather than relying on fixed resistive elements, thereby significantly reducing power loss while maintaining effective inrush current limitation.
Solution Approach 2:
The patent introduces dynamic control through controllable switches that can adjust their resistance characteristics in real-time based on operating conditions. The control unit dynamically adjusts the switching state to limit inrush current during capacitor charging while minimizing resistance during normal operation, thus reducing continuous power loss compared to static resistive circuits.
2Object-affected harmful factors
If a resistive passive current limiting circuit is used to reduce inrush current, then inrush current is limited, but volume of the power supply increases
Solution Approach 1:
The patent replaces bulky resistive passive current limiting components with compact active switching devices and control circuitry. The active current limiting circuit uses semiconductor switches and control units that occupy significantly less space than the large resistors and capacitors required for passive current limiting, thus reducing overall power supply volume.
3Stability of the object's composition
If the capacity of the bulk capacitor is increased to maintain voltage during transfer, then voltage stability is improved, but cost and volume increase
Solution Approach 1:
The patent implements preliminary action by detecting the power-off state of input power supply A in advance and activating the current limiting circuit before the transfer occurs. The control unit monitors the voltage across the bulk capacitor and proactively controls the switching devices to limit inrush current when voltage drops below a threshold, preventing the need for oversized capacitors to maintain voltage stability during transfer.
Solution Approach 2:
The patent uses feedback control by continuously monitoring the voltage across the bulk capacitor and adjusting the switching state of the current limiting circuit accordingly. When the voltage drops below a predetermined threshold during power transfer, the control unit activates the current limiting function, and when voltage is sufficient, it deactivates the limiting function, thereby maintaining voltage stability with smaller capacitor capacity.
4Adaptability or versatility
If an active current limiting circuit with multiple switches is used, then flexible control is achieved and power loss is reduced, but device complexity increases
Solution Approach 1:
The patent segments the current limiting function into multiple controllable switches (such as first and second switching devices) that can be independently controlled. This segmentation allows the control unit to selectively activate specific switches based on operating conditions, providing flexible control over current limiting while managing circuit complexity through modular design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Efficiently reduces inrush current, lowers power consumption, provides large power output, and ensures sufficient power to the load, with flexible control of current limiting switches.
Implementation Method 1
the current limiting switch unit is configured to turn on or off the multiple current limiting switches according to a current sampling signal in the current limiting switch unit or a current sampling signal in the power factor correction circuit and a result of comparison of voltages at a first end and a second end of the input bus
Data Source
AI summary
Embodiments of this disclosure provide an active current limiting circuit, a power supply device, a power supply system and a control method, wherein multiple current limiting switches in the active current limiting circuit are turned on or off according to the current sampling signal and the result of comparison of voltages obtained by sampling currents in the current limiting switch unit of the active current limiting circuit or currents in the power factor correction circuit and voltages at the first end and second end of the input bus. With the active current limiting circuit, the inrush current generated in switching the power supply lines may be efficiently reduced, power consumption may be lowered, output of large power may be provided, the capacitor may be charged and sufficient power output may be provided to the load. And furthermore, multiple current limiting switches may be flexibly controlled by using the current sampling signal and the result of comparison of the voltages at the two ends of the input bus, thereby improving operating efficiency of the current limiting circuit.