Switch Control Device for Converter Voltage Fluctuation Management
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Solution Overview
Problem
Conventional switch control devices fail to safely manage converters when input voltage is unstable or absent, leading to increased switch currents and potential damage during soft start operations, especially during blackouts or low voltage conditions.
Innovation Solution
A switch control device with a PWM controller, current sensor, and conditional counter that reduces switching duty and generates a disable signal when no input voltage is detected, using a logical operation of on pulse signals and current sense signals to manage power switch operations and determine turn-off times based on output voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the converter operates at maximum gain to compensate for decreasing output voltage during input voltage absence, then the output voltage is maintained, but a large current is generated when input voltage is restored causing damage to converter configuration
Solution Approach 1:
The control device performs preliminary detection of input voltage presence before allowing full power transmission. When no input voltage is detected, the device preemptively reduces the power transmission ratio to a predetermined level, preventing the accumulation of energy that would cause dangerous current surges when voltage is restored.
Solution Approach 2:
The system continuously monitors input voltage presence and dynamically adjusts the power transmission ratio based on this feedback. When input voltage is absent, the feedback loop maintains reduced transmission ratio; when voltage returns, the feedback mechanism gradually increases the ratio, preventing sudden current spikes.
2Reliability
If the switching duty is reduced to prevent large current, then converter damage is prevented, but the output voltage cannot be maintained during normal operation
Solution Approach 1:
The power transmission ratio is made dynamic rather than fixed. The system automatically adjusts the ratio between high power transmission mode (for normal operation) and low power transmission mode (for protection during input voltage absence), allowing optimal performance under different operating conditions.
Solution Approach 2:
The control device changes the power transmission ratio parameter based on input voltage detection. When input voltage is present, the ratio is set to maximum for efficient power transmission; when input voltage is absent, the ratio is reduced to prevent damage, thus adapting the system parameter to current operating conditions.
3Duration of action of stationary object
If the converter operates during blackout or low voltage conditions, then continuous power supply is maintained, but switch current sharply increases causing interruption in soft start operation
Solution Approach 1:
The control device detects input voltage absence in advance and preemptively reduces the power transmission ratio before the converter can accumulate excessive energy or experience current surges during blackout or low voltage conditions.
Solution Approach 2:
The system uses continuous monitoring of input voltage conditions with feedback control that adjusts the power transmission ratio in real-time, preventing switch current surges during blackout or low voltage events while maintaining safe operation.
Data Source
AI summary
The present invention relates to a switch control device and a converter including the same. According to an exemplary embodiment of the present invention, the switch control device includes a PWM controller for forcing a power switch to turn on when the power switch is turned off during a predetermined period, a current sensor for determining whether a current flows through the power switch, and a conditional counter for determining that an input voltage is input to a power transmission element by using a sense result of the current sensor and a number of times that the PWM controller turns on the power switch by force.