DC Power Supply Switching Control for Inrush Current Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power converting devices fail to suppress inrush currents during the operation start of switching elements, particularly when transitioning from full-wave rectification to double voltage operation or during restoration from a momentary stop.
Innovation Solution
A direct-current power supply device with a switching unit comprising a first and second switching element, controlled to gradually increase on-duty and extend the operation cycle, thereby reducing the inrush current by managing the switching frequency and on-duty cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If switching elements are operated to obtain output voltages higher than power supply voltages, then voltage boosting is achieved, but inrush current occurs during operation start
Solution Approach 1:
The control device performs preliminary action by gradually increasing the on-duty of switching elements from a first value to a second value before full operation. This gradual transition prevents inrush current by preparing the circuit in advance, allowing capacitors to charge progressively rather than suddenly when full power is applied.
Solution Approach 2:
The invention applies dynamics by making the on-duty of switching elements variable rather than fixed. The control device dynamically adjusts the on-duty from an initial first value to a final second value during operation start, and also dynamically extends the operation cycle. This dynamic control allows the system to adapt during startup to prevent inrush current while still achieving voltage boosting.
2Stability of the object's composition
If switching elements are operated continuously to maintain output voltage, then power supply stability is maintained, but inrush current cannot be suppressed during operation start
Solution Approach 1:
The control device applies periodic action by extending the operation cycle of switching elements during startup. Instead of continuous operation from the beginning, the switching elements operate with extended cycles that gradually decrease as the system stabilizes. This periodic control with varying cycle lengths allows inrush current suppression during startup while maintaining power supply stability during normal operation.
3Device complexity
If switching elements are operated with fixed on-duty to simplify control, then control complexity is reduced, but inrush current suppression is not achieved
Solution Approach 1:
The control device applies parameter changes by varying the on-duty parameter of switching elements during operation start. Instead of using a fixed on-duty value, the control device changes the on-duty from an initial first value to a final second value, and also changes the operation cycle. This parameter variation approach suppresses inrush current while maintaining relatively simple control logic through systematic parameter adjustment.
Data Source
AI summary
A direct-current power supply device includes a switching unit constituted by a first switching element and a second switching element and a control unit that controls the operations of the first witching element and the second switching element. The switching unit has a first mode in which on-duty is a first value and a second mode in which the on-duty is a second value larger than the first value. When transitioning the switching unit from the first mode to the second mode, the control unit controls the switching unit such that the time until the on-duty reaches the second value is equal to or longer than a fixed time and controls, after the on-duty reaches the second value, an operation cycle of the switching unit to extend the operation cycle.