IGBT (Insulated Gate Bipolar Transistor), insulated gate bipolar transistor, is a composite fully controlled voltage-driven power semiconductor device composed of BJT (bipolar transistor) and MOS (insulated gate field effect transistor), which has both MOSFETs. The advantages of both the high input impedance and the low turn-on voltage drop of the GTR. The GTR saturation voltage is reduced, the current carrying density is large, but the driving current is large; the MOSFET driving power is small, the switching speed is fast, but the conduction voltage drop is large, and the current carrying density is small. The IGBT combines the advantages of the above two devices, with low driving power and reduced saturation voltage. IGBT is very suitable for converter systems with DC voltages of 600V and above, such as AC motors, inverters, switching power supplies, lighting circuits, traction drives, etc. Figure 1 shows an N-channel reinforced insulated gate bipolar transistor structure. The N+ region is called the source region, and the electrode attached to it is called the source. The N+ zone is called the drain zone. The control region of the device is the gate region, and the electrode attached thereto is called the gate. The channel is formed next to the boundary of the gate region. The P-type region (including the P+ and P regions) between the drain and the source (the channel is formed in this region) is called a Subchannel region. The P+ region on the other side of the drain region is called the Drain injector. It is a unique functional region of the IGBT. Together with the drain region and the sub-channel region, it forms a PNP bipolar transistor that acts as an emitter. The drain injects holes and conducts conductive modulation to lower the on-state voltage of the device. The electrode attached to the drain implant region is called the drain. The switching function of the IGBT is to form a channel by adding a forward gate voltage, and provide a base current to the PNP transistor to turn on the IGBT. Conversely, the reverse gate voltage is applied to eliminate the channel, and the base current is cut off to turn off the IGBT. The driving method of the IGBT is basically the same as that of the MOSFET. It only needs to control the input pole N-channel MOSFET, so it has high input impedance characteristics. When the channel of the MOSFET is formed, the hole from the P+ base is injected into the N layer (small sub-), and the N layer is conductance modulated to reduce the resistance of the N layer, so that the IGBT is also low at high voltage. On-state voltage. 1, determine the polarity First, dial the multimeter in R&TImes; 1KΩ gear. When measuring with a multimeter, if the resistance of one pole and the other two poles is infinite, the resistance of the pole and the other poles is still infinity after the switch is changed, then the extreme gate is judged. ). The remaining two poles are measured by a multimeter. If the measured resistance is infinite, the measured resistance is smaller after changing the test leads. In the case where the resistance is small, it is judged that the red pen is connected to the collector (C); the black pen is connected to the emitter (E). 2, judge good or bad Place the multimeter in R&TImes; 10KΩ block, connect the IGBT collector (C) with a black pen, and connect the red pen to the emitter (E) of the IGBT. The pointer of the multimeter is at zero. Touch the gate (G) and the collector (C) with your finger at the same time. At this time, the IGBT is triggered to turn on. The pointer of the multimeter swings in the direction of smaller resistance and can stand at a certain position. Then touch the gate (G) and the emitter (E) with your finger at the same time, when the IGBT is blocked and the pointer of the multimeter returns to zero. At this point, the IGBT is judged to be good. 3. Any pointer type multimeter can be used to detect IGBT Pay attention to the IGBT when it is good or bad, be sure to set the multimeter in R&TImes; 10KΩ block, because the internal battery voltage of the multimeter below the R&TImes; 1KΩ block is too low, the IGBT can not be turned on when the test is good or bad, and it is impossible to judge whether the IGBT is good or bad. . This method can also be used to detect the quality of a power field effect transistor (P-MOSFET). Inverter IGBT module detection: Dial the digital multimeter to the diode test file and test the forward and reverse diode characteristics between the IGBT modules c1 e1 and c2 e2 and between the gate G and e1 and e2 to determine whether the IGBT module is intact. Take the six-phase module as an example. Remove the wires of the U, V, and W phases on the load side, use the diode test file, connect the red meter pen to P (collector c1), and the black test pen sequentially measures U, V, W. The multimeter displays the value as the maximum; the test pen is reversed, black The meter is connected to P, the red meter is measured U, V, W, and the multimeter displays a value of about 400. Then connect the red test pen to N (emitter e2), the black test pen to measure U, V, W, the multimeter display value is about 400; the black test pen is connected to P, the red test pen is measured U, V, W, and the multimeter displays the maximum value. The forward and reverse characteristics of each phase should be the same. If the difference indicates that the performance of the IGBT module is deteriorated, it should be replaced. When the IGBT module is damaged, only the breakdown short circuit occurs. The red and black test pens measure the forward and reverse characteristics between the gate G and the emitter E, respectively, and the values ​​measured by the multimeter are both maximum. At this time, it can be determined that the gate of the IGBT module is normal. If there is a numerical value, the gate performance deteriorates and the module should be replaced. When the forward and reverse test results are zero, it indicates that the detected one-phase gate has been broken through. When the gate is damaged, the voltage regulator of the circuit board protection gate will also be damaged by breakdown. Adapter Ring,Lens Adapter Ring,Camera Adapter Ring,Filter Adapter Ring SHAOXING COLORBEE PLASTIC CO.,LTD , https://www.colorbeephoto.com
January 21, 2023