company news

Application Analysis of IGBT Module of Inverter
(1) According to the working voltage and rated current of the load, as well as the frequency of use, select the module of the appropriate specification.
Before using the module, please read the module parameter data sheet in detail to understand the various technical indicators of the module; determine the use plan according to the technical parameters of the module, calculate the on-state loss and switching loss, and select the matching radiator and drive circuit.


(2) The use of IGBT modules


1. Preventing static electricity IGBT is a static sensitive device. In order to prevent the device from being harmed by static electricity, the following two points should be paid attention to:


① The black sponge on the drive terminal of the IGBT module is an anti-static material. When the user uses the lead of the connector, remove the anti-static material and insert the lead immediately; when there is no anti-static measure, do not touch the drive terminal by hand.


② When the drive terminals need to be soldered, the equipment or electric soldering iron must be grounded.


2. Selection and use


① Please use the product within the maximum rating (voltage, current, temperature, etc.) range. Once the maximum rating is exceeded, the product may be damaged, especially when the IGBT is applied with a voltage exceeding VCES, avalanche breakdown may occur and the component may be damaged. Please be sure to use it within the rated value range of VCES! The higher the working frequency, the smaller the working current; for reliability reasons, the safety factor must be considered.


② Drive circuit: Due to the trade-off relationship between IGBT Vce(sat) and short-circuit withstand capacity, it is recommended to select the gate voltage as +VGE=14～15V, -VGE=5～10V, to ensure that the drive on the drive terminal of the module is The voltage and waveform meet the driving requirements; the gate resistance Rg is closely related to the turn-on and turn-off characteristics of the IGBT, reducing the Rg value reduces switching losses, decreases the fall time, and increases the turn-off pulse voltage; on the contrary, when the gate resistance Rg value increases, It will increase the switching loss and affect the switching frequency; the appropriate Rg value should be selected according to the best compromise between the surge voltage and the switching loss (related to frequency), generally between 5Ω and 100Ω. In order to prevent the gate from being open, it is recommended to connect a 10K~20KΩ resistor in parallel between the gate and the emitter. The drive wiring should be as short as possible and use twisted-pair wires; when the power is turned on, please turn on the power of the drive control part first to make the drive circuit work, and then turn on the main circuit power.


③ Protection circuit: The wiring inductance of the IGBT module is prone to generate peak voltage when the high frequency is used. Attention must be paid to reducing the wiring inductance and the configuration of the components. The following protection items should be paid attention to: overcurrent protection, overvoltage protection, gate overvoltage and undervoltage protection , safe working area, over temperature protection.


④ Absorptive circuit: Due to the fast switching speed of IGBT, it is easy to generate surge voltage, and a surge clamp circuit must be provided.


⑤ Parallel use: The gate circuit, line wiring, current unbalance and temperature unbalance between devices should be considered, and positive temperature coefficient should be selected, and the saturation voltage drop should be at the same level (same batch).


⑥ Please avoid the place where corrosive gas and serious dust are generated when using.


(3) IGBT installation


① The radiator should be matched and selected according to the operating environment and module parameters to ensure the requirements for the radiator when the module is working.


② The surface finish of the radiator should be less than 10mm, and the plane distortion between each screw should be less than 10mm. If the surface of the heat sink is recessed, it will lead to an increase in the thermal contact resistance. In order to reduce the contact thermal resistance, it is recommended to apply a thin layer of thermal paste between the heat sink and the module. After the module is evenly stressed, it is best to see a little thermal paste extruded from the edge of the module. (It is best to use screen printing technology to print thermal paste on the surface of the heat sink)


③ When the module is installed on the radiator, the screws should be tightened with the torque given in the manual. Insufficient torque leads to increased thermal resistance or loose screws in motion. Excessive torque may damage the module shell or damage the module insulation;


④ When only one module is installed, install it in the center of the radiator to make the thermal resistance effect the best.


⑤ When installing several modules, corresponding space should be reserved according to the heating conditions of each module, and more space should be reserved for modules with large heat generation.


⑥ When installing tightening screws at two points, first tighten 1/3 of the rated torque in turn, and then reverse the rated torque.


⑦ The four-point installation is similar to the two-point installation, and the long direction of the IGBT follows the pattern of the heat sink. When tightening the screws, tighten 1/3 of the rated torque diagonally in turn, and then reach the rated torque in reverse order.


⑧ When using a radiator with a texture, the long direction of the IGBT follows the texture of the radiator to reduce the deformation of the radiator. When two modules are installed on a radiator, they should be placed side by side in a short direction, leaving a sufficient distance in the middle, mainly to reduce heat accumulation when the fan dissipates heat, easy to dissipate heat, and maximize the efficiency of the radiator.


The second is that the module terminals are easy to connect, which is beneficial to reduce stray inductance, especially when it is used at high frequencies.


⑨ When connecting devices, the bus bar connecting the module should not cause excessive mechanical and thermal stress to the main terminal electrodes of the module, so as to prevent the internal welding of the module electrodes from breaking or the heating of the electrode terminals to cause overheating on the module.