Before answering "What is an IGBT module?", let's first understand its function: The IGBT power module is the power "core" of industrial electric drives, frequency converters, UPS, and inverters and other equipment. It is responsible for converting direct current to alternating current to drive motors or grid-connected power generation, and can also rectify alternating current for energy storage and grid-connected power generation.
Before making a selection, the following three points should be mainly considered: electrical parameters (which directly determine the overall operating loss of the machine), thermal performance parameters (which affect the heat dissipation design and the lifespan of components), and reliability parameters (short-circuit tolerance, power cycle life, ensuring the long-term stable operation of the equipment in the field).
Its application scenarios include: frequency converters, motor drives, UPS systems, solar power generation, etc.
This article will provide a comprehensive analysis of the working principle and application of IGBT power modules. Whether you are a purchasing manager, engineer, or manufacturer, this article will help you establish a decision-making framework.
I. What is an IGBT Module? – Internal Analysis
The component behind the switch
IGBT (Insulated Gate Bipolar Transistor) is a three-terminal power semiconductor device that possesses two key characteristics:
Similar to MOSFETs, it has high input impedance - voltage-driven and easy to control
Similar to BJTs, it has low on-state loss - capable of handling large currents with a lower on-state voltage.
From chips to modules
A single IGBT chip is merely the basic power unit. The IGBT power module integrates multiple IGBT chips with fast recovery diodes (FRED) in the same package. It is arranged according to mainstream topologies such as half-bridge, full-bridge, three-level, and chopper. Inverter operation modules are generally equipped with FRED current-limiting diodes.
The typical module consists of a three-layer structure:
- Copper substrate - quickly conducts the heat from the chip to the heat sink
- DBC copper-clad ceramic substrate - electrical insulation and thermal conductivity
- Silicon chip (IGBT chip + diode chip) - actually performs the switching function
- Most industrial-grade modules also integrate NTC temperature sensors to monitor the junction temperature in real time, achieving precise over-temperature protection. The IGBT module we launched also adopts this temperature measurement design.
The actual function of the module
The IGBT power module is essentially a high-speed electronic switch.
It can achieve:
- DC to AC conversion (inverter) - for driving motors, photovoltaic grid connection
- AC to DC conversion (rectification) - for power supply, charging equipment
- PWM pulse width modulation for voltage/current regulation
2. Core technologies within the module
The internal manufacturing techniques between IGBT modules determine the loss characteristics, switching behavior and reliability.
Sag Channel/Gate-Off Field Stop Structure
Most of the current modern industrial IGBT modules, including those designed by us, adopt the sag channel/gate-off field stop technology. This design structure enables the module to withstand higher voltages under the same power loss, or generate lower power loss under the same voltage, ultimately achieving a dual improvement in system efficiency and reliability.
Integrating NTC temperature detection
Heat management is a key factor affecting the lifespan of IGBT modules. Our IGBT module is equipped with an integrated NTC thermistor, which provides real-time temperature data feedback to the control system, enabling precise temperature control.
Copper substrate + standard packaging
The thermal conductivity of copper is much higher than that of aluminum, allowing for faster and more uniform heat conduction. This directly shortens the cycle of power circulation.
Standard packaging ensures compatibility with existing system designs, reducing the cost and risks associated with module upgrades.
3. Selection Guide: Essential Information for Purchasers and Engineers
The key to choosing high-performance IGBTs for inverter drives lies in finding the module that best matches the actual working conditions.
The three crucial electrical parameters are as shown in the table:
| Parameter |
Definition |
Impact on Component Selection |
| VCE(sat) — Saturation Voltage Drop |
Tube voltage drop when the IGBT is fully turned on |
Determines conduction loss |
| Eon/Eoff — Switching Energy |
Energy lost during turn-on and turn-off processes |
Determines switching loss |
| RthJC — Junction-to-Case Thermal Resistance |
Thermal conduction resistance from chip junction to module case |
Determines heat dissipation requirements |
The three reliability dimensions of High-Reliability Industrial-Grade IGBT Modules
Take our 1200V/600A IGBT module as an example:
① Voltage Margin
The bus voltage fluctuation and the peak of the turn-off voltage will increase the pressure on the device, thus requiring sufficient voltage margin to be reserved. This module has a 1200V rating and is compatible with 600-800V bus systems. Even when the stray inductance layout is not optimized, there is still sufficient peak resistance margin.
② Short-Circuit Tolerance
Short-circuit faults have a circuit protection response window period. The short-circuit capability determines whether the module can perform protection delay within microseconds without damaging itself. This module has excellent short-circuit tolerance performance, enhancing the overall fault tolerance capability.
③ Rated Maximum Junction Temperature (Tvj op = 150℃)
Junction temperature is the core factor determining the lifespan of an IGBT. For every 10°C exceeding the rated value, the device lifespan is halved. A rated junction temperature of 150°C can handle frequent startups, short-term overloads, and poor heat dissipation conditions. Moreover, in actual conditions, it is recommended to keep the long-term junction temperature within 120°C, leaving a 30°C thermal buffer to cope with transient high temperatures and device aging.
4. Where are IGBT modules applied?
For example, our IGBT modules can be applied in four typical areas:
| Application Field |
Core Function |
Key Requirements for Modules |
| Frequency Converter |
Convert DC bus into variable-frequency three-phase AC power to realize motor speed regulation |
High reliability, long service life, resistance to frequent start-stop operations |
| Motor Drives |
Deliver power drive for industrial equipment |
High current capacity (600A), long power cycle lifetime |
| UPS Uninterruptible Power Supply |
Rapidly switch to battery power supply once mains power cuts off |
Fast response speed, high reliability |
| Solar Power Generation |
Convert PV DC power into grid-tied AC power |
High efficiency, excellent resistance to outdoor environments |
5. Common Questions
Q1: What are the advantages of the trench gate/field stop structure?
The trench gate eliminates the JFET resistance in the planar design, significantly reducing the on-state voltage drop; the field stop layer optimizes the electric field distribution and simultaneously reduces the switching loss. It achieves a balanced optimization of on-state loss and switching loss.
Q2: What is the purpose of integrating NTC?
The NTC thermistor provides real-time temperature data for the control system module. It enables precise over-temperature protection, preventing situations of delayed protection or failure.
Q3: What are the most common failure modes of IGBT modules?
Mainly include: overcurrent damage, overvoltage breakdown, overheating failure, and fatigue of the solder layer caused by power cycling.
And the IGBT module we have launched provides sufficient engineering margin in all these aspects through a 1200V withstand voltage, high short-circuit capacity and 150°C junction temperature design. This enables the entire machine to maintain reliability during long-term operation.
6. Designed for real working conditions
Choosing the right IGBT module is like selecting a reliable "heart" for the drive system. As long as the correct and high-quality power module is chosen, it can largely prevent potential problems that may occur during the long-term operation of the system.
We design our products based on actual working conditions, with the sole aim of achieving the following: parameters serve performance, and performance ensures stability.
For more information on different types of IGBT modules, please visit our official website.
If you need detailed technical data of the products, sample applications or selection support, please contact our engineering technical team:wisedrv@wiseelec.cn
