Panasonic inverter fault handling - Solutions - Huaqiang

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Due to the lower range of use of Panasonic inverters, we have made relatively few summaries in the maintenance of Panasonic inverters. The following authors discuss some common faults of Panasonic inverters and discuss them:
(1) Power-on and no display In the maintenance of DV707 series inverter, the fault that I often encounter is power-on and no display, exclude external power supply, display and other factors. In most cases, the switching power supply is damaged. In maintenance, we can It is noted that the pulse transformer of DV707 series inverter is a relatively easy to damage device. Due to the influence of high frequency magnetic conductive material, load capacity, short circuit overcurrent protection circuit design of switching power supply, etc., it is easy to be on the primary winding side of pulse transformer. The phenomenon of burnout occurs. Because the skeleton design of the pulse transformer is different from the general step-up/step-down transformer, it is not easy to disassemble. Sometimes, after the disassembly, the magnetic material will crack open, and the closed magnetic field at the joint will have a gap. The pulse transformer cannot be normal. jobs. In general, replace the pulse transformer.
In addition, the design of the DV707 series inverter switching power supply is still different from other inverters. It uses an integrated block of model MA2810, which integrates the switching power tube and the clamp regulator tube and other components in one, which makes the peripheral circuit of the switching power supply reduced, but the damage probability of MA2810 in maintenance is still higher.
(2) Inverter module damage In the VF-7F series inverter, sometimes the inverter module is damaged. A more common phenomenon is that the inverter suddenly loses power during normal operation, and the inverter cannot start the motor after being powered on again. After checking the damage of the inverter module, the reason is mainly because the inverter is still under the control of the running command after the power failure, and at this time, the intermediate DC voltage drops sharply due to the consumption of the load of the motor and the consumption of the inverter itself, which is easy to cause The PWM modulated wave signal changes, resulting in damage to the power module. Generally, in this case, the drive circuit is not easily damaged. When the inverter module is replaced, the inverter can resume normal operation. In such cases, it is best to take measures on the control circuit to block the inverter output when the power is cut off.
(3) Damage to the drive circuit In the maintenance of the DV707 series inverter, the inverter module is often damaged and the drive circuit is also damaged. No negative voltage in the drive circuit is a common phenomenon in the damage of the drive circuit. DV707 series inverters use Fuji's PIM module on the power device, which belongs to the IGBT type. It is known that the IGBT high-power tube is of a voltage-conducting type. In the absence of negative voltage, the IGBT cannot be effectively turned off, resulting in mis-conduction. Negative pressure is generally generated by a Zener diode. This is also the most common damage. If replaced, the drive waveform should return to normal.
(4) LV failure
LV failure is also one of the phenomena that can often be encountered during maintenance. Especially in the DV700 series inverter. After eliminating the problem of the external power supply problem, the problem should be more than the detection circuit failure. The sample is taken through the step-down resistor and sent to the main control board through the optocoupler isolation signal. The step-down resistor and the isolated optocoupler may be damaged. After replacement, the machine should be able to return to normal.