Full-Bridge Power Converter Phase Control for Overcurrent Prevention
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Solution Overview
Problem
Power converters face a risk of overcurrent flow through transformers, power converting circuits, and resistive loads when a resistive load is connected to the power receiving terminal, leading to a voltage difference between the power transmitting and receiving coils.
Innovation Solution
Incorporating a power receiving voltage sensor to measure voltage at the power receiving terminals and adjusting the phase difference between switch activations in the full-bridge circuit to minimize the voltage difference between the power transmitting and receiving coils, thereby reducing the risk of overcurrent flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resistive load is connected to the power receiving terminal, then the voltage at the power receiving terminal decreases to 0V, but this causes an increased voltage difference between the power transmitting coil and power receiving coil leading to overcurrent risk
Solution Approach 1:
The patent applies dynamics by making the phase difference between the first and third switches variable rather than fixed. The controller dynamically adjusts the phase difference based on the detected voltage at the power receiving terminal. When voltage decreases (indicating resistive load connection), the phase difference is increased to reduce the voltage difference across the transformer, thereby preventing overcurrent while allowing resistive load operation.
2Reliability
If the phase difference between first switch and third switch activation is decreased, then the voltage difference between power transmitting coil and power receiving coil is reduced, but this requires dynamic adjustment based on voltage sensing
Solution Approach 1:
The patent implements feedback by using the power receiving terminal voltage sensor to continuously monitor voltage levels and feed this information back to the controller. The controller then adjusts the phase difference between switches based on this feedback signal. This closed-loop control system automatically prevents overcurrent conditions without requiring complex external control mechanisms, as the system self-regulates based on real-time voltage conditions.
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
This solution effectively decreases the phase difference between switch activations, minimizing the risk of overcurrent flow and ensuring safe operation by maintaining a stable voltage difference across the transformer and resistive load.
Implementation Method 1
a transformer which includes a power transmitting coil and a power receiving coil, the power transmitting coil being connected to the full-bridge circuit, the power receiving coil being connected to the power converting circuit and magnetically coupled with the power transmitting coil
Data Source
AI summary
A power converter includes a full-bridge circuit, power converting circuit, transformer, and controller. The full-bridge circuit includes a series-connected unit made of first and second switches and a series-connected unit made of third and fourth switches and is connected to power transmitting terminals. The power converting circuit is connected to power receiving terminals. The transformer includes power transmitting coil and power receiving coil. The power transmitting coil is connected to full-bridge circuit. The power receiving coil is connected to power converting circuit. The controller turns on the first and second switches alternately and also the third and fourth switches alternately. A resistive load is connected to the power receiving terminals. The controller serves to determine a phase difference between the time when first switch is turned on and the time when third switch is turned on to decrease with a decrease in measured voltage developed at the power receiving terminals.