Power Supply Holding-Up Time During Voltage Dips
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Solution Overview
Problem
Conventional power supply devices provide inadequate holding-up time during voltage dips, failing to meet International Electro Technical Commission requirements due to instability in external power sources.
Innovation Solution
A power supply device incorporating a voltage dividing circuit, transformers, and an output stage circuit that selectively generates an output voltage based on a comparison of input voltage with a threshold, ensuring continuous output when the input voltage is stable and stopping output when it drops below the threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional power supply device is used, then the device structure is simple, but the holding-up time during voltage dips is very short and cannot meet IEC requirements
Solution Approach 1:
The power supply device is segmented into multiple functional modules: voltage detecting unit (comparator 230), pulse generating unit (oscillator 202), pulse width controlling unit (PWM controller 204), and output stage. This segmentation allows each module to perform its specific function efficiently, achieving extended holding-up time during voltage dips while maintaining manageable device complexity through modular design.
Solution Approach 2:
The voltage detecting unit continuously monitors the input voltage and generates comparison voltages in advance before voltage dips occur. The pulse generating unit pre-configures the oscillator to generate clock pulses that can be immediately modulated by the PWM controller when voltage instability is detected, enabling rapid response without waiting for voltage collapse.
2Reliability
If the power supply device continuously outputs during voltage dips, then the output stability is maintained, but the device cannot adapt to severe voltage conditions and fails IEC requirements
Solution Approach 1:
The voltage detecting unit continuously compares the input voltage against a reference voltage and feeds back the comparison result to the PWM controller. This feedback mechanism allows the system to dynamically adjust the pulse width modulation duty cycle based on real-time voltage conditions, maintaining output stability during mild dips while adapting to severe conditions by reducing or stopping output when necessary to meet IEC requirements.
Solution Approach 2:
The PWM controller dynamically adjusts the duty cycle of the output pulses based on the comparison voltage from the voltage detecting unit. During voltage dips, the system transitions from continuous output to pulse-width modulated output, and can further transition to stopped output when voltage falls below threshold, providing dynamic adaptability to varying voltage conditions while maintaining reliability.
3Reliability
If the power supply device stops outputting when voltage drops below threshold, then IEC requirements are met, but the productivity is reduced during voltage dip events
Solution Approach 1:
Instead of completely stopping output during all voltage dip conditions, the PWM controller applies partial action by maintaining reduced-duty-cycle output during mild voltage dips. The system only stops outputting when the voltage drops below the threshold set by the voltage detecting unit, providing excessive protection margin while maintaining productivity during less severe conditions. This partial action approach balances IEC compliance with continuous operation during acceptable voltage ranges.
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 significantly increases the holding-up time during voltage dips, achieving higher output stability and meeting IEC requirements, suitable for various electronic devices.
Implementation Method 1
The first transformer generates a transformation voltage and a feedback voltage according to the input voltage
Implementation Method 2
The second transformer generates a control voltage according to the comparison voltage
Data Source
AI summary
A power supply device includes a voltage dividing circuit, a first transformer, a comparator, a second transformer, and an output stage circuit. The voltage dividing circuit generates a reference voltage according to an input voltage. The first transformer generates a transformation voltage and a feedback voltage according to the input voltage. The comparator compares the feedback voltage with the reference voltage to generate a comparison voltage. The second transformer generates a control voltage according to the comparison voltage. The output stage circuit selectively generates an output voltage according to the transformation voltage and the control voltage. If the RMS (Root-Mean-Square) value of the input voltage is higher than or equal to a threshold voltage, the output stage circuit will continuously output the output voltage. If the RMS value of the input voltage is lower than the threshold voltage, the output stage circuit will stop outputting the output voltage.