Power Converter Controller Adjusts Delay Time for Voltage Stability
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Solution Overview
Problem
Conventional power converters experience instability and voltage fluctuations when changing the number of switching operations of the short circuit unit in response to load conditions, leading to potential overvoltage, insufficient voltage, or operation stoppages.
Innovation Solution
A power converter that includes a controller to adjust the delay time and on-time of the driving signal for the short circuit unit, allowing for controlled changes in the number of switching operations during the half cycle of the AC power supply, thereby stabilizing the DC voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of switching operations is changed according to load condition, then power factor and harmonics are improved, but DC voltage fluctuates causing instability
Solution Approach 1:
The patent applies dynamics by making the delay time variable rather than fixed. The control device dynamically adjusts the delay time before the short circuit unit operates, based on the number of switching operations detected in the previous half cycle. This allows the system to adapt to changing load conditions while maintaining stable DC voltage output.
Solution Approach 2:
The patent implements feedback by using the detection result of switching operations from the previous half cycle to control the delay time in the current half cycle. The control device counts switching operations, detects when the number changes, and uses this information to adjust subsequent delay times, creating a closed-loop control system that maintains voltage stability.
2Device complexity
If delay time is not adjusted when changing switching operations, then control is simple, but DC voltage becomes unstable causing overvoltage or insufficient voltage
Solution Approach 1:
The system performs self-service by automatically detecting changes in the number of switching operations and autonomously adjusting the delay time accordingly. The control device monitors switching operations, detects changes, and modifies the delay time without external intervention, enabling the system to self-regulate and maintain voltage stability.
3Ease of operation
If short circuit time is not controlled appropriately, then switching operation is simple, but DC voltage control becomes unstable affecting load operation
Solution Approach 1:
The patent applies parameter changes by modifying the delay time parameter based on the detected number of switching operations. When the control device detects a change in switching operation count, it adjusts the delay time parameter to an appropriate value, thereby maintaining stable DC voltage control while keeping the switching operation itself relatively simple.
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
The solution effectively prevents voltage fluctuations and ensures stable operation by adjusting the delay time and on-time of the driving signal, improving power factor and reducing harmonics while maintaining system stability.
Implementation Method 1
a reactor (2) connected between the AC power supply (1) and the rectifier (3)
Implementation Method 2
a short circuit unit (30) that short-circuits the AC power supply (1) via the reactor (2)
Implementation Method 3
a rectifier (3) that converts AC voltage from the AC power supply (1) into DC voltage
Implementation Method 4
a smoothing capacitor (5) that smoothes the voltage
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A power converter includes a rectifier 3 that converts AC power from an AC power supply 1 into DC power, a short circuit unit 30 that short-circuits the AC power supply 1 via a reactor 2, and a controller 20 that controls the short circuit operation of the short circuit unit 30. The controller 20 changes the number of the short circuit operation during a half cycle of an output waveform of the AC power supply on the basis of a load condition, and causes a delay time before short circuit from a zero crossing point of the output waveform of the AC power supply after changing the number of the short circuit operation to vary from a delay time before short circuit from a zero crossing point of the output waveform of the AC power supply before changing the number of the short circuit operation.