Common Fault Treatment of Panasonic Inverter

Panasonic inverter is a brand of inverter developed and sold by Panasonic Group of Japan. Panasonic inverter has advanced technology, simple and convenient operation, stable working performance, high safety and reliability, and can also play a lot of self-protection role. However, although it has so many advantages, some faults will still occur during use, which is a common problem of electronic products.

In the maintenance of DV707 series inverters, the fault that is often encountered is no display after power-on. Excluding external power supply, display and other factors, in most cases, it is the damage of the switching power supply. During the maintenance, we can notice that the pulse transformer of the DV707 series inverter is a device that is more easily damaged. Due to the influence of some factors such as high-frequency magnetic conductive materials, load capacity, short-circuit overcurrent protection circuit design of the switching power supply, the primary winding side of the pulse transformer is prone to burnout. Since the skeleton design of the pulse transformer is different from that of the general step-up/step-down transformer, it is not easy to disassemble. Often after disassembly, the magnetic conductive material will crack, and there will be a gap in the closed magnetic field at the connection, and the pulse transformer cannot work normally. Generally, replace the pulse transformer.

In addition, the design of the DV707 series inverter switching power supply is different from other inverters. It uses an integrated block of model MA2810, which integrates switching power tubes, clamping voltage regulator tubes and other components, reducing the peripheral circuits of the switching power supply. However, the probability of damage to MA2810 is still relatively high during maintenance.

(1) No display when the Panasonic inverter is powered on

In the maintenance of DV707 series inverters, the fault that the author often encounters is no display after power-on. Excluding external power supply, display and other factors, in most cases it is the damage of the switching power supply. During the maintenance, we can notice that the pulse transformer of the DV707 series inverter is a device that is more easily damaged. Due to the influence of some factors such as high-frequency magnetic conductive materials, load capacity, short-circuit overcurrent protection circuit design of the switching power supply, the primary winding side of the pulse transformer is prone to burnout. Because the skeleton design of the pulse transformer is different from that of the general step-up/step-down transformer, it is not easy to disassemble. Often after disassembly, the magnetic conductive material will crack, and there will be a gap in the closed magnetic field at the connection, and the pulse transformer cannot work normally. Generally, replace the pulse transformer.

In addition, the design of the DV707 series inverter switching power supply is different from other inverters. It uses an integrated block model MA2810, which integrates switching power tubes, clamping voltage regulator tubes and other components, reducing the peripheral circuits of the switching power supply. However, the probability of damage to MA2810 during maintenance is still relatively high.

(2) Panasonic inverter inverter module is damaged

In VF-7F series inverters, the inverter module is sometimes damaged. A common phenomenon is that the inverter suddenly loses power during normal operation, causing the inverter to be unable to start the motor after powering on again. After checking the inverter module damage, the main reason is that the inverter is still under the control of the running command after the power outage. At this time, due to the consumption of the load carried by the motor and the consumption of the inverter itself, the intermediate DC voltage drops sharply, which easily causes the PWM modulation wave signal to change, resulting in damage to the power module. Generally, in this case, the drive circuit is not easy to be damaged. Replace the inverter module and the inverter can resume normal operation. In such a situation, it is best to take measures on the control circuit to block the inverter output at the moment of power outage.

(3) Panasonic inverter drive circuit is damaged

In the maintenance of DV707 series inverters, it is often encountered that the inverter module is damaged while the drive circuit is also damaged. The lack of negative pressure in the drive circuit is a common phenomenon of drive circuit damage. DV707 series inverters use Fuji's PIM module for power devices, which belongs to the IGBT type. As we all know, IGBT high-power tubes are voltage-conducting types. In the absence of negative pressure, the IGBT will not be able to be effectively turned off, resulting in misconduction. Negative pressure is generally generated by the voltage-stabilizing diode, which is also the most common damage part. Replace it and the drive waveform should return to normal.

(4) Panasonic inverter LV failure

LV failure is also one of the phenomena that can be often encountered during maintenance. Especially in DV700 series inverters. After excluding the external power supply problem, the most common problem should be the detection circuit failure. The sampling is done through the voltage drop resistor, and the optocoupler signal is sent to the main control board for processing after being isolated by the optocoupler. The voltage drop resistor and the isolation optocoupler may be damaged. After replacement, the machine should be able to return to normal.