Boost Chopper Control Device Preventing Overvoltage via Capacitor Discharge
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Solution Overview
Problem
Conventional power supply control devices using boost choppers can experience overvoltage issues when input voltage suddenly increases, leading to potential component destruction due to widened switching control without adequate capacitor charge reduction.
Innovation Solution
A power supply control device that includes a switch control unit using oscillation waves to control the ON/OFF of a switching device, a comparison voltage generating unit to charge/discharge a comparison capacitor, an input increase detecting unit to sense current increases, and an output voltage detecting unit to manage DC output voltage, with a discharging unit to prevent overvoltage by extending the switching device's OFF period when detection criteria are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feedback control using error amplifier is used to maintain output voltage, then output voltage stability is improved, but response speed to sudden input voltage changes deteriorates
Solution Approach 1:
The control device performs preliminary action by detecting sudden input voltage increases before they cause overvoltage, and preemptively adjusting the switching device ON-width to prevent the harmful effect from occurring
Solution Approach 2:
The control device uses feedback by continuously monitoring the relationship between input voltage and switching duration, and adjusts the switching device ON-width based on this feedback to maintain stable output voltage while responding quickly to input changes
2Power
If switching device ON-width is increased to handle input voltage increase, then power supply capacity is improved, but output voltage control precision deteriorates due to overvoltage
Solution Approach 1:
The control device applies dynamics by making the switching device ON-width adjustable and variable rather than fixed, allowing it to be dynamically optimized based on real-time input voltage conditions to simultaneously achieve high power capacity and precise voltage control
Solution Approach 2:
The control device changes parameters by adjusting the switching device ON-width according to the detected relationship between input voltage and switching duration, optimizing the operating parameters to maintain both high power supply capacity and precise output voltage control
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
Prevents component destruction by reducing the ON-width of the switching device and maintaining stable output voltage during sudden input voltage increases, effectively managing overvoltage risks and ensuring device reliability.
Implementation Method 1
a comparison voltage generating unit configured to charge or discharge a comparison capacitor that generates a comparison voltage for comparison with the oscillation wave in correspondence with a DC output voltage
Implementation Method 2
the error amplifier outputs current corresponding to a voltage difference between a divided voltage of a DC output voltage inputted to an inverting input terminal and a reference voltage connected to a non-inverting input terminal
Data Source
AI summary
A power supply control device includes a switch control unit configured to control ON/OFF of a switching device of a boost chopper by using an oscillation wave, a comparison voltage generating unit configured to charge or discharge comparison capacitor that generates a comparison voltage for comparison with the oscillation wave in correspondence with a DC output voltage outputted from the boost chopper, an input increase detecting unit configured to detect whether a detection value corresponding to current flowing through the boost chopper has increased to or above a detection criterion, an output voltage detecting unit configured to detect whether the DC output voltage is at or above the lower limit voltage, a discharging unit configured to discharge the comparison capacitor when the detection value has increased to or above the detection criterion and the DC output voltage is at or above the lower limit voltage.