Variable Duty Cycle Boost Converter for Voltage Sag Ride-Through
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current power protection devices are unable to provide effective ride-through during voltage sags, as they focus primarily on protecting equipment from damage rather than maintaining operation during momentary electrical disturbances, and existing boost converters suffer from slow response times and high costs.
Innovation Solution
A low-cost system incorporating a variable duty cycle boost converter, energy clamp circuit, and control circuit to detect voltage sags and provide temporary boosted voltage to loads, while preventing excess voltage from damaging connected equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional boost converter is used to correct voltage sags, then voltage compensation can be provided, but the response time is slow and the cost is high
Solution Approach 1:
The patent applies dynamics by making the duty cycle of the boost converter variable rather than fixed. The control circuit dynamically adjusts the duty cycle based on the severity of the voltage sag, allowing the system to respond quickly to different disturbance levels. This dynamic adjustment enables fast response time while maintaining effective voltage compensation, resolving the contradiction between reliability and response time.
2Reliability
If a voltage sag corrector system is added to provide ride-through functionality, then equipment operation is maintained during voltage sags, but the system complexity and cost increase
Solution Approach 1:
The patent implements multi-functionality by designing a voltage sag corrector that simultaneously provides ride-through capability and voltage spike protection. The energy clamp circuit with switch and capacitor not only clamps voltage spikes but also works integrally with the boost converter to maintain output voltage during sags. This unified approach maintains equipment operation during voltage sags without requiring separate protection devices, thereby reducing overall system complexity while preserving reliability.
3Reliability
If the boost converter operates continuously to maintain voltage, then voltage stability is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by operating the boost converter in pulsed cycles rather than continuously. The control circuit monitors the input voltage and activates the boost converter only when voltage sags are detected. During normal voltage conditions, the converter remains inactive or operates at minimal duty cycle. This periodic operation maintains voltage stability when needed while minimizing energy consumption during normal conditions, resolving the contradiction between reliability and energy use.
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 system effectively maintains equipment operation during voltage sags by providing temporary power and preventing voltage spikes, offering a cost-effective solution for frequent power disturbances.
Implementation Method 1
an apparatus that compensates for voltage sags by using a variable duty cycle boost converter to boost the line voltage to predetermined desired voltage levels
Implementation Method 2
The disclosed system includes a selectively actuatable boost converter for providing a boosted voltage to the load. Also provided is a circuit for detecting a voltage sag in the input AC line voltage
Data Source
AI summary
A sag corrector apparatus for providing voltages temporarily (ride-through) to a load during momentary electrical disturbances in the power supply line. In one embodiment, the disclosed apparatus compensates for voltage sags by using a variable duty cycle boost converter to boost the sagged line voltage to resemble desired voltage levels during occurrence of voltage sags. The boosted voltage available to a connected load during a sag depends on a sequence of operation of various control pulses. Duty cycle of the boost converter is controlled by changing the width (duration) of the control pulses. To prevent voltage shoot-throughs from over-boosting, an energy clamp circuit is provided to dissipate excess energy. Embodiments of the sag corrector circuit can be additionally integrated with power protection functions.