Power Semiconductor Switch Series Circuit Voltage Equalization
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Solution Overview
Problem
High voltage and high power converters require multiple power semiconductor switches in series, but existing solutions face issues with high power consumption, slow switching speed, inconsistent switching actions, and vulnerability to overcurrent, leading to potential device damage and reduced reliability.
Innovation Solution
A power semiconductor switch series circuit with multiple series modules, each comprising a power semiconductor switch, a drive module, a short-circuit detection unit, an equalizer circuit, a comparison module, and a soft turn-off module, along with a system control module that performs static and dynamic voltage equalization and detects short-circuit conditions to ensure safe and synchronized turn-off of switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If multiple power semiconductor switches are directly connected in series to achieve high voltage capability, then the voltage withstand capability is improved, but the switching actions become inconsistent due to different device performance and circuit distributed parameters, leading to overvoltage damage
Solution Approach 1:
The patent divides the series circuit into multiple independent series modules, each with its own drive module, short-circuit detection unit, equalizer circuit, and protection circuits. This segmentation allows independent control and protection of each module, improving switching consistency and preventing overvoltage damage while maintaining high voltage capability.
Solution Approach 2:
The patent implements feedback mechanisms through short-circuit detection units that monitor each power semiconductor switch, comparison modules that compare detection signals with thresholds, and system control modules that coordinate turn-off actions. This feedback ensures consistent switching actions and prevents overvoltage damage by detecting and responding to abnormal conditions.
2Stress or pressure
If conventional devices such as thyristor or GTO are used for series connection, then the voltage capability is improved, but the power consumption increases and switching speed decreases
Solution Approach 1:
The patent changes the key parameter of the power semiconductor device from conventional thyristor/GTO to IGBT, which has fundamentally different electrical characteristics including faster switching speed and lower power consumption. This parameter change enables the device to meet PWM converter requirements while maintaining high voltage capability through series connection.
3Ease of operation
If IGBT devices are used in series circuit with same gate control signal circuit, then the device consistency is improved, but the switching actions remain inconsistent due to different device performance and distributed circuit parameters, causing overvoltage exceeding rated value
Solution Approach 1:
The patent applies local quality by providing each series module with its own dedicated equalizer circuit and protection circuits, allowing each module to be optimized and controlled independently. This local customization compensates for device performance variations and prevents overvoltage damage despite using identical gate control signal circuits.
Solution Approach 2:
The patent implements beforehand cushioning through equalizer circuits that perform static and dynamic voltage equalization, and protection circuits that are activated before overvoltage damage can occur. These measures cushion against voltage imbalances and prevent overvoltage exceeding rated values.
4Reliability
If short-circuit detection and protection circuits are added to each series module, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent segments the protection function into modular components (short-circuit detection unit, comparison module, soft turn-off module, equalizer circuit) that can be independently implemented and maintained in each series module. This modular segmentation improves reliability through comprehensive protection while managing complexity through standardization.
Solution Approach 2:
The patent implements universal protection circuits that can be applied to each series module with the same structure and functionality. The short-circuit detection unit, comparison module, and soft turn-off module serve multiple functions including detection, decision-making, and execution, reducing overall system complexity through functional integration.
Data Source
AI summary
The present disclosure provides a power semiconductor switch series circuit. The power semiconductor switch series circuit includes a plurality of series modules and a system control module. Each series module has a power semiconductor switch; a drive module for driving each power semiconductor switch to be turned on or turned off; a short-circuit detection unit for outputting at least one detection signal; an equalizer circuit; a comparison module for comparing the detection signal with a predetermined threshold, and outputting a short-circuit signal when the detection signal exceeds the predetermined threshold; and a soft turn-off module for receiving the short-circuit signal and outputting a second control signal. The system control module receives the short-circuit signal and outputs a first control signal.