Series Power Switch Overvoltage Protection Circuit
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Solution Overview
Problem
In high voltage and high power converters, series-connected power switch devices like IGBTs face issues with inconsistent switching speeds and overvoltage damage due to distributed inductance and capacitance, leading to reliability concerns in PWM current transformation applications.
Innovation Solution
A power switch series circuit with detection and control modules, including optical couplers for voltage detection and amplification, and voltage balance modules to prevent overvoltage damage by synchronously turning off power switches when an overvoltage is detected, using IGBTs and additional components like capacitors and diodes for dynamic voltage balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple IGBTs are connected in series to achieve high voltage capability, then the voltage withstand capability is improved, but the switching consistency deteriorates due to distributed inductance and capacitance
Solution Approach 1:
The patent applies preliminary action by detecting overvoltage conditions before they cause damage to the IGBTs. The detection module continuously monitors voltage across each IGBT and triggers protective action in advance when abnormal voltage distribution is detected, preventing the switching inconsistency from leading to device failure.
Solution Approach 2:
The patent implements feedback through the detection module that monitors voltage across each IGBT and feeds this information to the control module. When overvoltage is detected on any IGBT, the control module receives feedback and adjusts the switching signals to all IGBTs to turn them off simultaneously, correcting the switching inconsistency in real-time.
2Strength
If conventional power devices like thyristor or GTO are used for series connection, then the voltage withstand capability is improved, but the switching speed and power consumption deteriorate
Solution Approach 1:
The patent applies parameter changes by selecting IGBTs with specific electrical parameters optimized for both high voltage capability and fast switching. The detection and control modules are configured with specific voltage thresholds and response times that optimize the balance between voltage withstand capability and switching speed, allowing the system to achieve both goals simultaneously.
3Adaptability or versatility
If IGBTs with different performance characteristics are used in series connection, then the adaptability is improved, but the voltage distribution uniformity deteriorates leading to overvoltage damage
Solution Approach 1:
The patent applies local quality by implementing individual voltage detection for each IGBT in the series connection. The detection module monitors the voltage across each specific IGBT separately, allowing the system to handle IGBTs with different performance characteristics by providing localized monitoring and protection rather than relying on uniform voltage distribution across all devices.
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 effectively prevents overvoltage damage to power switches, enhancing the reliability and operation of power switch series circuits by ensuring synchronized shutdown of power switches during overvoltage conditions, thus improving the overall performance and safety of high-voltage converter systems.
Implementation Method 1
The isolation unit is an optical coupler. In some embodiments, the optical coupler includes a light-emitting semiconductor and a light-receiving semiconductor.
Implementation Method 2
The optical coupler includes a light-emitting semiconductor and a light-receiving semiconductor. The light-emitting semiconductor and the detection unit are connected in series.
Implementation Method 3
The light-receiving semiconductor is connected to the control module.
Data Source
AI summary
The present invention provides a power switch series circuit and its control method. The power switch series circuit includes a plurality of series modules, a control module and a drive module. At least one series module has a power switch and a detection module, and the detection module includes a detection unit and an isolation unit, so as to detect the overvoltage and output a voltage detection signal based on the detected voltage. The control module receives the voltage detection signal and outputs the corresponding control signal. The drive module amplifies the control signal to drive each power switch to turn ON or turn OFF. The control module outputs the corresponding control signal to turn off each power switch when the overvoltage happens.