IGBT Switch Circuit with Active Clamping for Overvoltage Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
IGBT switch circuits in electrically driven motor vehicles face damage from overvoltage spikes during power disconnection and high reverse potentials when the electric machine becomes a generator, leading to potential false switching and protection circuit damage.
Innovation Solution
An IGBT switch circuit with an active clamping protection circuit, including a transient suppression diode and a PMOS switch, is used to manage overvoltage spikes and prevent false switching, featuring a control circuit that issues a square wave signal to maintain the switch in a closed state during power disconnection and control the switching of the active clamping circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an IGBT circuit is used to drive the electric machine system, then the motor vehicle can be driven efficiently, but overvoltage spikes occur during power disconnection causing IGBT damage
Solution Approach 1:
The control circuit proactively detects the disconnection state of the electric machine system and activates the clamping protection circuit before the overvoltage spike can damage the IGBT. The control circuit monitors the working state and issues a square wave signal to turn on the PMOS switch in advance, establishing the protection path ahead of time.
Solution Approach 2:
The PMOS switch acts as an intermediary element between the IGBT circuit and the clamping protection circuit. When activated, it connects the clamping protection circuit to the IGBT output, providing a controlled path for the overvoltage energy and protecting the IGBT from direct exposure to damaging voltage spikes.
2Speed
If the electric machine operates at high speed as a generator, then high reverse potential is produced increasing bus voltage, but this causes the IGBT to switch on erroneously or damages the protection circuit
Solution Approach 1:
The system dynamically adjusts the state of the PMOS switch based on real-time operating conditions. During high-speed generator operation, the control circuit maintains the PMOS switch in a closed state to continuously provide protection against reverse potential and overvoltage, allowing the system to adapt to changing electrical conditions.
Solution Approach 2:
The control circuit continuously monitors the working state of the electric machine system and uses this feedback to control the PMOS switch. When high reverse potential or overvoltage conditions are detected, the feedback mechanism ensures the protection circuit remains active, preventing false switching and damage.
3Reliability
If a protection circuit is added to protect the IGBT, then IGBT damage from overvoltage is prevented, but the device complexity increases
Solution Approach 1:
The PMOS switch serves multiple functions: it acts as a normal switching element in the IGBT circuit, serves as a protection pathway activator for overvoltage events, and functions as a controlled connector to the clamping protection circuit. This multi-functionality reduces the need for separate dedicated protection components.
Solution Approach 2:
The protection system is self-regulating through the control circuit that automatically detects dangerous conditions and activates the appropriate protection mechanisms without external intervention. The system monitors itself and responds autonomously to threats, reducing the need for complex external control systems.
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
Effectively suppresses overvoltage spikes and prevents IGBT damage, ensuring reliable operation even during high-speed generator modes by maintaining the protection circuit's functionality and avoiding erroneous switching.
Implementation Method 1
protection circuit comprises a transient suppression diode and a second diode connected in series
Implementation Method 2
a PMOS switch, is used to manage overvoltage spikes and prevent false switching
Implementation Method 3
an IGBT circuit serving as a modulating switch between an electric machine and a load thereof
Implementation Method 4
parasitic inductance will arise in each circuit branch... the parasitic inductance of the branches will give rise to an induced voltage due to the sharp change in input current
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present invention provides an electric machine system and an IGBT switch circuit thereof, wherein the IGBT switch circuit comprises: an IGBT circuit (2011, 2012, 2013, 2014, 2015, 2016), comprising a bipolar junction transistor (T21) and a first diode (d21) connected in parallel, the IGBT circuit (2011, 2012, 2013, 2014, 2015, 2016) serving as a modulating switch between an electric machine (200) and a load (100) thereof; an active clamping protection circuit (P) coupled to the IGBT circuit (2011, 2012, 2013, 2014, 2015, 2016); a switch (S2) also being connected between the IGBT circuit (2011, 2012, 2013, 2014, 2015, 2016) and the protection circuit (P). The present invention can solve the problem of damage to the IGBT caused by overvoltage at the output of the bipolar junction transistor in the IGBT when the IGBT is switched off. Moreover, the present invention can also solve the technical problem of the IGBT being switched on erroneously or the active clamping circuit being damaged.