Abstract: Taking the ACS510 series inverter used in the auxiliary network system of Ningxia Dam Power Generation Co., Ltd. as an example, the common faults of the inverter, the fault diagnosis displayed on the control panel of the inverter, and the common faults of the external circuit of the inverter are analyzed. The faults and general processing methods that may occur during the use of the inverter are described for reference.
Introduction According to statistics, the average power generation coal consumption of Ningxia Dam Power Generation Co., Ltd. is 338g/(kWh), which is much higher than that of developed countries. One of the main reasons is that the power consumption rate of the plant is obviously high, and the operation efficiency of the auxiliary machinery of the main plant is inefficient. Therefore, the plant electricity rate has been hovering around 6.22% for a long time. According to the analysis of on-site data, there are several reasons:
1) With the continuous improvement of the management level of Ningxia Dam Power Generation Co., Ltd., the air leakage and the leakage rate have been significantly reduced, which has caused a significant power margin problem for fans and pumps, making the phenomenon of “big horse-drawn cars†prominent.
2) The installed capacity of Ningxia Dam Power Generation Co., Ltd. is 4×300MW. The machine assembly capacity is relatively large. Sometimes the power supply capacity of the power grid becomes affluent. The unit is in a low-load operation state for a long time, and the load coefficient of the unit is floating at 50%~70%. Deterioration of the operating economy of auxiliary power plants.
3) Due to the change of the load structure of the power grid, the peak-to-valley difference of the load is widened. Sometimes, the unit also needs to participate in peak and peak adjustment and deep peak operation. The auxiliary flow regulation method cannot fully meet the requirements of peak regulation, and energy waste and regulation characteristics also occur. Deteriorated situation.
Therefore, in order to control the power consumption rate of the plant and improve the economic benefits of Ningxia Dam Power Generation Co., Ltd., the new frequency conversion speed control technology is applied in the main auxiliary drive system. It has become one of the main technical measures for the energy-saving transformation of the auxiliary drive system of Ningxia Dam Power Generation Co., Ltd.
With the continuous progress and development of modern enterprises, the maximization of benefits is the eternal theme of the company. The use of new technologies to improve the management level of enterprise production equipment and energy saving is one of the first choices for companies. The development of frequency converters is also constantly introducing new features, increasing functionality and increasing reliability. However, if it is used improperly, it is operated incorrectly, maintenance is not timely, failures may occur, or changes in operating conditions may shorten the life of the equipment. Therefore, daily maintenance and overhaul work is particularly important.
Most of the auxiliary network systems of Ningxia Dam Power Generation Co., Ltd. adopt the ACS510 series inverter manufactured by ABB, and take this as an example for the common faults of the inverter, the fault diagnosis displayed on the inverter control panel, and the external circuit of the inverter. Failure analysis:
First, the common alarm analysis of the inverter 1.1 Inverter charging start circuit alarm ACS510 series inverter is generally voltage type inverter, using the AC - DC - AC work. When the frequency converter is just powered on, because the capacity of the flat wave capacitance on the DC side is very large and the charging current is very large, a starter resistor is usually used to limit the charging current. After charging is complete, the control circuit shorts the resistors through the relay contacts or thyristors. Startup circuit faults typically appear as start-up resistor burnouts. The ACS510 series drive alarm displays an OVERVOLTAGE overvoltage alarm. In order to reduce the size of the inverter and choose a smaller starting resistance, its value is mostly 10-50Ω, power is 10-50W; when the frequency converter's AC input power is frequently turned on, or the contact of the bypass contact is bad, it will Causes the starting resistor to burn out. Therefore, while replacing the resistor, it is necessary to find out the reason. If the fault is caused by the frequency of the power supply at the input side, this phenomenon must be eliminated to put the inverter into service. If the fault is caused only by the bypass contactor element, it must be replaced. These devices.
1.2 Inverter has no fault alarm, but it can not run at high speed. After checking the parameters of the ACS510 series inverter are set correctly, the speed input signal is normal. After the power running test, the inverter DC bus voltage is only about 450V (normally should be 580V-600V), Remeasure the input side and find a missing phase. The fault is caused by a poor contact of an air switch on the input side. Causes the frequency changer to lack the phase to report to the police, still can work in the low frequency band, because most frequency changers the bus voltage lower limit is 400V, only when the bus line voltage drops below 400V, the frequency changer reports the breakdown. When the two phases are input, the DC bus voltage is 380V×1.2=452V>400V. When the frequency converter is not running, due to the role of the flat wave capacitance, the DC voltage can reach the normal value. The new inverter adopts the PWM control technology. The work of voltage regulation and frequency modulation is completed in the inverter bridge, so the input phase is low in the low frequency band. Can still work normally, but because of the input voltage, the output voltage is low, causing the asynchronous motor to rotate at a low frequency.
1.3 Inverter Display Overcurrent Alarm When OVERCURRENT overcurrent alarm appears on the ACS510 series inverter, first check if the acceleration time parameter is too short and if the torque boost parameter is too large, then check if the load is too heavy. If there is no such phenomenon, the current transformer on the output side and the Hall current detection point on the DC side can be disconnected and run after reset to see if an over-current phenomenon occurs. If yes, it is likely that the IPM module has failed because the IPM module contains overvoltage, undervoltage, overload, overheat, phase loss, short circuit and other protection functions. These fault signals are output via the module control pin. The pin is transmitted to the controller. After the controller receives the fault information, it blocks the pulse output on the one hand and displays the fault information on the panel on the other hand. The IPM module should be replaced.
1.4 Inverter displays overvoltage alarm ACS510 series inverter has overvoltage fault and displays as OVERVOLTAGE overvoltage alarm. Generally it is thunderstorm. Since the lightning is strung into the inverter's power supply, the voltage detector on the DC side of the inverter trips. In this case, it is usually only necessary to disconnect the power supply of the inverter for about 1 minute and then turn on the power. In another case, the inverter drives a large inertia load and an over-voltage phenomenon occurs. In this case, one is to increase the deceleration time parameter or increase the braking resistance (brake unit); the other is to set the stop mode of the inverter to freewheeling mode.
1.5 If the motor generates heat, the inverter displays an overload alarm. If the MOTOVERTEMP motor overheating alarm occurs on the ACS510 series inverter, the load status must be checked for the inverter that has been put into operation. For newly installed inverters, this type of fault is likely to be V/F. If the curve is incorrectly set or there is a problem with the motor parameter setting, various parameters must be correctly set. In addition, the motor's heat dissipation performance will deteriorate when operating at a low frequency. This situation may also occur. In this case, a heat sink device must be installed. Motor heating, mainly based on the inverter or temperature feedback value. This kind of alarm message indicates that the motor is overloaded and the tripping is about to occur. The overload condition of the motor and the temperature sensor should be checked.
2. Fault Diagnosis Analysis Displayed on the Control Panel of the Inverter 2.1 DCUNDERVOLT Fault Display on the Control Panel When DCUNDERVOLT fault code appears in the ACS510 series inverter, the inverter is in undervoltage fault status. The main reason is that the input power supply is too low or the phase is missing, the internal voltage detection circuit of the inverter is abnormal, and the inverter main circuit is abnormal. The universal inverter voltage input range is 320V~460V. Under the full load operation of the inverter in practical applications, undervoltage protection may occur when the input voltage is lower than 340V. At this time, the input voltage of the grid or derating of the inverter should be used; If the input voltage is normal, and the inverter has a DCUNDERVOLT fault during operation, it can be judged as an internal fault of the inverter. If the main loop of the inverter is normal, the cause of the DCUNDERVOLT alarm is mostly the fault of the voltage detection circuit. Generally, the voltage detection circuit of the inverter is a switch. A set of outputs of the power supply is sent to the CPU processor after sampling and comparison circuits. When the set value is exceeded, the CPU outputs a fault block signal according to the comparison signal to block the IGBT and display the fault code. At the same time, external loops must also be inspected, such as phase loss of power supply, blown fuses, and undervoltage of the main power supply.
2.2 Display of the DCOVERVOLT/OVERCURRENT fault on the control panel When a DCUNDERVOLT/OVERCURRENT fault appears on the ACS510 series inverter, it indicates that the inverter has overvoltage or overcurrent fault during deceleration. The main reason is that the motor is overloaded. The deceleration time is too short and the load feedback energy is too large to be released in time. If the motor drives a large inertia load, when the frequency of the inverter (that is, the synchronous speed of the motor) decreases, the actual speed of the motor may be greater than the synchronous speed. At this time, the motor is in a state of power generation. This part of the energy will pass through the inverter circuit of the inverter. Return to the DC loop so that the inverter has overvoltage or overcurrent protection. During the on-site treatment, the deceleration time of the inverter can be prolonged without affecting the production process. If the inertia of the load is large and the inverter is required to stop within a certain period of time, an external braking resistor and braking unit must be installed. The ACS510 series inverter All models below 22kW have a built-in braking unit. Only an external braking resistor can be added. The resistance matching can be selected according to the standard in the product description. For models with a power above 22kW, an additional braking unit and braking resistor are required. .
DCOVERVOLT/OVERCURRENT faults usually appear only during inverter deceleration and shutdown. If the inverter fails under other operating conditions, it may be part of the internal switching power supply of the inverter. For example, the voltage detection circuit or current detection circuit is abnormal. Caused by.
2.3 Displaying the CURRMEAS (current measurement) fault diagnosis on the control panel The ACS510 series inverter indicates a current detection fault when a CURRMEAS fault is displayed. The general inverter current detection generally uses a current sensor. The inverter is detected by detecting the two-phase output current of the inverter. Running current detection, display and protection functions, the output current is output by the current sensor linear voltage signal, the amplified comparison circuit is sent to the CPU processor, the CPU processor according to different signals to determine whether the inverter is in over-current status, if the output current exceeds protection Value, the failure to block the protection circuit action, block IGBT pulse signal, to achieve protection.
When the ACS510 series inverter displays a CURRMEAS fault, the main cause is a fault in the current sensor or an abnormality in the current detection and amplification comparator circuit. The former can be solved by replacing the sensor. The latter is mostly an abnormal current in the related current detection IC circuit or IC chip. Related ICs or repair related power solutions.
2.4 Diagnosis of EARTHFAULT (earth fault) on the control panel Fault of EARBUSAULT in ACS510 series Inverter indicates fault of IPM and IGBT of inverter module. The main reason is that the output is shorted to ground and the cable from inverter to motor is too long (exceeds). 50m), inverter module or its protection circuit is faulty. Remove the motor cable at the site, measure the inverter inverter module, observe whether the output is short-circuited, and check whether the motor is shorted to ground and whether the motor line exceeds the allowable range. If the above conditions are normal, it may be the internal IGBT module of the inverter. Drive or protection circuit is abnormal. The general IGBT over-current protection is operated by detecting the voltage drop of the tube when the IGBT is turned on.
When the IGBT is normally turned on, its saturation voltage drop is very low. When the IGBT is overcurrent, the tube voltage drop VCE will increase with the increase of the short-circuit current. When the IGBT is increased to a certain value, the detection diode DB will conduct reverse conduction. The reverse current signal is sent to the CPU processor via the IGBT drive protection circuit, and the CPU blocks the IGBT output for protection. If the detection diode DB is damaged, the ACS510 series inverter will display an EARTHFAULT fault display, and the detection diode can be replaced to eliminate the fault.
When an EARTHFAULT fault appears on the ACS510 series inverter, a ground fault may be detected at the motor or motor cable. When the inverter is running or stopped, the ACS510 series inverter can monitor the ground fault. When the inverter is stopped, the ground fault monitoring has higher sensitivity and can report the location of the fault. When the ACS510 series inverter has an EARTHFAULT fault display, it should also do the following:
1) Check the discharge line ground fault;
2) Check that the length of the cable from the inverter to the motor does not exceed the maximum length allowed;
3) If the input power supply is a delta connection, and the input power cable has a large capacitance, it may result in the occurrence of a ground fault in case of a stop operation. This type of ground fault can be set to exit by mistake.
2.5 Diagnosis of DEVOVEHTEMP (overheating) on ​​the control panel When a DEVOVEHTEMP fault is displayed on the ACS510 series inverter, it indicates that the inverter is overheated. The possible causes are: fan failure, air flow obstruction, radiator dust, and excessive ambient temperature. The cooling fan is damaged and the motor load is too large and the temperature detection circuit is abnormal. When processing on-site, first judge whether the inverter is actually overheated. If the temperature is too high, the fault can be eliminated first. If the DEVOVEHTEMP alarm occurs when the temperature of the inverter is normal, the cause of the fault is the fault of the temperature detection circuit. The seven-unit inverter module used in the ABB22kW models has internal temperature components. If this part of the module fails, DEVOVEHTEMP alarm will also appear. On the other hand, the same fault phenomenon will occur when the temperature detection operation circuit is abnormal.
Third, the external circuit of the inverter analysis of common faults The external circuit of the inverter can be roughly divided into two parts, one part is responsible for the start/stop operation of the inverter control circuit; the other part is responsible for the inverter signal transmission signal circuit, Now take the ACS510 series inverter of Ningxia Dam Power Generation Co., Ltd. as an example to analyze the common faults of the external circuit of the inverter.
3.1 Inverter start / stop control loop analysis of common faults Inverter control loop is generally divided into local and remote, the so-called local operation is to control the frequency control motor start / stop by the inverter's own control function to achieve, do not pass Contactor start/stop. This part is mainly realized by the internal frequency converter, so no analysis is done here. The other part is remote operation. The remote operation can be divided into inverter cabinet operation and remote computer remote operation. Inverter cabinet operation can not achieve the start / stop of the inverter, first check the start / stop button of the inverter cabinet, the fault of the button is a little more, followed by the inspection of the terminal wiring and relay in the cabinet; When the host computer cannot perform remote operation, terminals on the terminal block should be located to realize the remote start/stop operation of the host computer and short-circuited. If the inverter can start/stop after short-circuiting, it means that the cable between the host computer or the connection between the host computer and the inverter cabinet is faulty. Check the discharge gradually; otherwise, check the terminal wiring and relay in the cabinet. In order to achieve the remote operation of the inverter.
3.2 Inverter signal loop analysis of common faults The signal circuit of the inverter is the circuit that transfers the signal between the inverter and the host computer. If the signal loop fails, it will result in loss of signal or wrong transmission of the signal, which will affect the normal operation of the inverter. Operation, because the signal loop is mostly a weak current signal of 4-20mA, it is easy to connect the wrong line and it is not easy to find. For example, once the inverter's current upload signal and the frequency upload signal were incorrectly connected, it caused the operator to make an erroneous decision. When such a fault is encountered, only the current and current signals can be analyzed, and the frequency and rate signals can be uploaded. Change the situation, check the cable and loop number, and correct it after confirming it is correct; between the host computer and the inverter there is a signal transmission of the given amount and feedback amount. If these two quantities are reversed, the inverter cannot realize remote Operation, if you encounter such a fault, first find out the terminals of the given quantity and feedback signal from the terminal block, turn it on, and then use the active signal generator to add 4-20mA current signal to the circuit, if After the signal is added, the corresponding frequency can be displayed on the inverter, indicating that the loop is a given signal loop of the host computer to the inverter; if the signal is added to the upper machine, the corresponding frequency can be displayed, indicating that the loop is the upper inverter. Machine feedback loop signal.
IV. Concluding remarks With the continuous expansion of the application range of frequency converters, technicians are becoming more familiar with the frequency converters. The problems that occur during the use of frequency converters are roughly similar. The ACS510 series inverters used in the auxiliary network system of Ningxia Dam Power Generation Co., Ltd. are used. For example, the common faults of the inverter, the fault diagnosis displayed on the control panel of the inverter, and the common faults of the external circuit of the inverter are analyzed. The possible faults and general processing methods of the ACS510 series inverter in use are described. It is hoped that the technical personnel at the production site will be able to deal with the defects as soon as possible, and at the same time, it is for the reference of the industry insiders.
Introduction According to statistics, the average power generation coal consumption of Ningxia Dam Power Generation Co., Ltd. is 338g/(kWh), which is much higher than that of developed countries. One of the main reasons is that the power consumption rate of the plant is obviously high, and the operation efficiency of the auxiliary machinery of the main plant is inefficient. Therefore, the plant electricity rate has been hovering around 6.22% for a long time. According to the analysis of on-site data, there are several reasons:
1) With the continuous improvement of the management level of Ningxia Dam Power Generation Co., Ltd., the air leakage and the leakage rate have been significantly reduced, which has caused a significant power margin problem for fans and pumps, making the phenomenon of “big horse-drawn cars†prominent.
2) The installed capacity of Ningxia Dam Power Generation Co., Ltd. is 4×300MW. The machine assembly capacity is relatively large. Sometimes the power supply capacity of the power grid becomes affluent. The unit is in a low-load operation state for a long time, and the load coefficient of the unit is floating at 50%~70%. Deterioration of the operating economy of auxiliary power plants.
3) Due to the change of the load structure of the power grid, the peak-to-valley difference of the load is widened. Sometimes, the unit also needs to participate in peak and peak adjustment and deep peak operation. The auxiliary flow regulation method cannot fully meet the requirements of peak regulation, and energy waste and regulation characteristics also occur. Deteriorated situation.
Therefore, in order to control the power consumption rate of the plant and improve the economic benefits of Ningxia Dam Power Generation Co., Ltd., the new frequency conversion speed control technology is applied in the main auxiliary drive system. It has become one of the main technical measures for the energy-saving transformation of the auxiliary drive system of Ningxia Dam Power Generation Co., Ltd.
With the continuous progress and development of modern enterprises, the maximization of benefits is the eternal theme of the company. The use of new technologies to improve the management level of enterprise production equipment and energy saving is one of the first choices for companies. The development of frequency converters is also constantly introducing new features, increasing functionality and increasing reliability. However, if it is used improperly, it is operated incorrectly, maintenance is not timely, failures may occur, or changes in operating conditions may shorten the life of the equipment. Therefore, daily maintenance and overhaul work is particularly important.
Most of the auxiliary network systems of Ningxia Dam Power Generation Co., Ltd. adopt the ACS510 series inverter manufactured by ABB, and take this as an example for the common faults of the inverter, the fault diagnosis displayed on the inverter control panel, and the external circuit of the inverter. Failure analysis:
First, the common alarm analysis of the inverter 1.1 Inverter charging start circuit alarm ACS510 series inverter is generally voltage type inverter, using the AC - DC - AC work. When the frequency converter is just powered on, because the capacity of the flat wave capacitance on the DC side is very large and the charging current is very large, a starter resistor is usually used to limit the charging current. After charging is complete, the control circuit shorts the resistors through the relay contacts or thyristors. Startup circuit faults typically appear as start-up resistor burnouts. The ACS510 series drive alarm displays an OVERVOLTAGE overvoltage alarm. In order to reduce the size of the inverter and choose a smaller starting resistance, its value is mostly 10-50Ω, power is 10-50W; when the frequency converter's AC input power is frequently turned on, or the contact of the bypass contact is bad, it will Causes the starting resistor to burn out. Therefore, while replacing the resistor, it is necessary to find out the reason. If the fault is caused by the frequency of the power supply at the input side, this phenomenon must be eliminated to put the inverter into service. If the fault is caused only by the bypass contactor element, it must be replaced. These devices.
1.2 Inverter has no fault alarm, but it can not run at high speed. After checking the parameters of the ACS510 series inverter are set correctly, the speed input signal is normal. After the power running test, the inverter DC bus voltage is only about 450V (normally should be 580V-600V), Remeasure the input side and find a missing phase. The fault is caused by a poor contact of an air switch on the input side. Causes the frequency changer to lack the phase to report to the police, still can work in the low frequency band, because most frequency changers the bus voltage lower limit is 400V, only when the bus line voltage drops below 400V, the frequency changer reports the breakdown. When the two phases are input, the DC bus voltage is 380V×1.2=452V>400V. When the frequency converter is not running, due to the role of the flat wave capacitance, the DC voltage can reach the normal value. The new inverter adopts the PWM control technology. The work of voltage regulation and frequency modulation is completed in the inverter bridge, so the input phase is low in the low frequency band. Can still work normally, but because of the input voltage, the output voltage is low, causing the asynchronous motor to rotate at a low frequency.
1.3 Inverter Display Overcurrent Alarm When OVERCURRENT overcurrent alarm appears on the ACS510 series inverter, first check if the acceleration time parameter is too short and if the torque boost parameter is too large, then check if the load is too heavy. If there is no such phenomenon, the current transformer on the output side and the Hall current detection point on the DC side can be disconnected and run after reset to see if an over-current phenomenon occurs. If yes, it is likely that the IPM module has failed because the IPM module contains overvoltage, undervoltage, overload, overheat, phase loss, short circuit and other protection functions. These fault signals are output via the module control pin. The pin is transmitted to the controller. After the controller receives the fault information, it blocks the pulse output on the one hand and displays the fault information on the panel on the other hand. The IPM module should be replaced.
1.4 Inverter displays overvoltage alarm ACS510 series inverter has overvoltage fault and displays as OVERVOLTAGE overvoltage alarm. Generally it is thunderstorm. Since the lightning is strung into the inverter's power supply, the voltage detector on the DC side of the inverter trips. In this case, it is usually only necessary to disconnect the power supply of the inverter for about 1 minute and then turn on the power. In another case, the inverter drives a large inertia load and an over-voltage phenomenon occurs. In this case, one is to increase the deceleration time parameter or increase the braking resistance (brake unit); the other is to set the stop mode of the inverter to freewheeling mode.
1.5 If the motor generates heat, the inverter displays an overload alarm. If the MOTOVERTEMP motor overheating alarm occurs on the ACS510 series inverter, the load status must be checked for the inverter that has been put into operation. For newly installed inverters, this type of fault is likely to be V/F. If the curve is incorrectly set or there is a problem with the motor parameter setting, various parameters must be correctly set. In addition, the motor's heat dissipation performance will deteriorate when operating at a low frequency. This situation may also occur. In this case, a heat sink device must be installed. Motor heating, mainly based on the inverter or temperature feedback value. This kind of alarm message indicates that the motor is overloaded and the tripping is about to occur. The overload condition of the motor and the temperature sensor should be checked.
2. Fault Diagnosis Analysis Displayed on the Control Panel of the Inverter 2.1 DCUNDERVOLT Fault Display on the Control Panel When DCUNDERVOLT fault code appears in the ACS510 series inverter, the inverter is in undervoltage fault status. The main reason is that the input power supply is too low or the phase is missing, the internal voltage detection circuit of the inverter is abnormal, and the inverter main circuit is abnormal. The universal inverter voltage input range is 320V~460V. Under the full load operation of the inverter in practical applications, undervoltage protection may occur when the input voltage is lower than 340V. At this time, the input voltage of the grid or derating of the inverter should be used; If the input voltage is normal, and the inverter has a DCUNDERVOLT fault during operation, it can be judged as an internal fault of the inverter. If the main loop of the inverter is normal, the cause of the DCUNDERVOLT alarm is mostly the fault of the voltage detection circuit. Generally, the voltage detection circuit of the inverter is a switch. A set of outputs of the power supply is sent to the CPU processor after sampling and comparison circuits. When the set value is exceeded, the CPU outputs a fault block signal according to the comparison signal to block the IGBT and display the fault code. At the same time, external loops must also be inspected, such as phase loss of power supply, blown fuses, and undervoltage of the main power supply.
2.2 Display of the DCOVERVOLT/OVERCURRENT fault on the control panel When a DCUNDERVOLT/OVERCURRENT fault appears on the ACS510 series inverter, it indicates that the inverter has overvoltage or overcurrent fault during deceleration. The main reason is that the motor is overloaded. The deceleration time is too short and the load feedback energy is too large to be released in time. If the motor drives a large inertia load, when the frequency of the inverter (that is, the synchronous speed of the motor) decreases, the actual speed of the motor may be greater than the synchronous speed. At this time, the motor is in a state of power generation. This part of the energy will pass through the inverter circuit of the inverter. Return to the DC loop so that the inverter has overvoltage or overcurrent protection. During the on-site treatment, the deceleration time of the inverter can be prolonged without affecting the production process. If the inertia of the load is large and the inverter is required to stop within a certain period of time, an external braking resistor and braking unit must be installed. The ACS510 series inverter All models below 22kW have a built-in braking unit. Only an external braking resistor can be added. The resistance matching can be selected according to the standard in the product description. For models with a power above 22kW, an additional braking unit and braking resistor are required. .
DCOVERVOLT/OVERCURRENT faults usually appear only during inverter deceleration and shutdown. If the inverter fails under other operating conditions, it may be part of the internal switching power supply of the inverter. For example, the voltage detection circuit or current detection circuit is abnormal. Caused by.
2.3 Displaying the CURRMEAS (current measurement) fault diagnosis on the control panel The ACS510 series inverter indicates a current detection fault when a CURRMEAS fault is displayed. The general inverter current detection generally uses a current sensor. The inverter is detected by detecting the two-phase output current of the inverter. Running current detection, display and protection functions, the output current is output by the current sensor linear voltage signal, the amplified comparison circuit is sent to the CPU processor, the CPU processor according to different signals to determine whether the inverter is in over-current status, if the output current exceeds protection Value, the failure to block the protection circuit action, block IGBT pulse signal, to achieve protection.
When the ACS510 series inverter displays a CURRMEAS fault, the main cause is a fault in the current sensor or an abnormality in the current detection and amplification comparator circuit. The former can be solved by replacing the sensor. The latter is mostly an abnormal current in the related current detection IC circuit or IC chip. Related ICs or repair related power solutions.
2.4 Diagnosis of EARTHFAULT (earth fault) on the control panel Fault of EARBUSAULT in ACS510 series Inverter indicates fault of IPM and IGBT of inverter module. The main reason is that the output is shorted to ground and the cable from inverter to motor is too long (exceeds). 50m), inverter module or its protection circuit is faulty. Remove the motor cable at the site, measure the inverter inverter module, observe whether the output is short-circuited, and check whether the motor is shorted to ground and whether the motor line exceeds the allowable range. If the above conditions are normal, it may be the internal IGBT module of the inverter. Drive or protection circuit is abnormal. The general IGBT over-current protection is operated by detecting the voltage drop of the tube when the IGBT is turned on.
When the IGBT is normally turned on, its saturation voltage drop is very low. When the IGBT is overcurrent, the tube voltage drop VCE will increase with the increase of the short-circuit current. When the IGBT is increased to a certain value, the detection diode DB will conduct reverse conduction. The reverse current signal is sent to the CPU processor via the IGBT drive protection circuit, and the CPU blocks the IGBT output for protection. If the detection diode DB is damaged, the ACS510 series inverter will display an EARTHFAULT fault display, and the detection diode can be replaced to eliminate the fault.
When an EARTHFAULT fault appears on the ACS510 series inverter, a ground fault may be detected at the motor or motor cable. When the inverter is running or stopped, the ACS510 series inverter can monitor the ground fault. When the inverter is stopped, the ground fault monitoring has higher sensitivity and can report the location of the fault. When the ACS510 series inverter has an EARTHFAULT fault display, it should also do the following:
1) Check the discharge line ground fault;
2) Check that the length of the cable from the inverter to the motor does not exceed the maximum length allowed;
3) If the input power supply is a delta connection, and the input power cable has a large capacitance, it may result in the occurrence of a ground fault in case of a stop operation. This type of ground fault can be set to exit by mistake.
2.5 Diagnosis of DEVOVEHTEMP (overheating) on ​​the control panel When a DEVOVEHTEMP fault is displayed on the ACS510 series inverter, it indicates that the inverter is overheated. The possible causes are: fan failure, air flow obstruction, radiator dust, and excessive ambient temperature. The cooling fan is damaged and the motor load is too large and the temperature detection circuit is abnormal. When processing on-site, first judge whether the inverter is actually overheated. If the temperature is too high, the fault can be eliminated first. If the DEVOVEHTEMP alarm occurs when the temperature of the inverter is normal, the cause of the fault is the fault of the temperature detection circuit. The seven-unit inverter module used in the ABB22kW models has internal temperature components. If this part of the module fails, DEVOVEHTEMP alarm will also appear. On the other hand, the same fault phenomenon will occur when the temperature detection operation circuit is abnormal.
Third, the external circuit of the inverter analysis of common faults The external circuit of the inverter can be roughly divided into two parts, one part is responsible for the start/stop operation of the inverter control circuit; the other part is responsible for the inverter signal transmission signal circuit, Now take the ACS510 series inverter of Ningxia Dam Power Generation Co., Ltd. as an example to analyze the common faults of the external circuit of the inverter.
3.1 Inverter start / stop control loop analysis of common faults Inverter control loop is generally divided into local and remote, the so-called local operation is to control the frequency control motor start / stop by the inverter's own control function to achieve, do not pass Contactor start/stop. This part is mainly realized by the internal frequency converter, so no analysis is done here. The other part is remote operation. The remote operation can be divided into inverter cabinet operation and remote computer remote operation. Inverter cabinet operation can not achieve the start / stop of the inverter, first check the start / stop button of the inverter cabinet, the fault of the button is a little more, followed by the inspection of the terminal wiring and relay in the cabinet; When the host computer cannot perform remote operation, terminals on the terminal block should be located to realize the remote start/stop operation of the host computer and short-circuited. If the inverter can start/stop after short-circuiting, it means that the cable between the host computer or the connection between the host computer and the inverter cabinet is faulty. Check the discharge gradually; otherwise, check the terminal wiring and relay in the cabinet. In order to achieve the remote operation of the inverter.
3.2 Inverter signal loop analysis of common faults The signal circuit of the inverter is the circuit that transfers the signal between the inverter and the host computer. If the signal loop fails, it will result in loss of signal or wrong transmission of the signal, which will affect the normal operation of the inverter. Operation, because the signal loop is mostly a weak current signal of 4-20mA, it is easy to connect the wrong line and it is not easy to find. For example, once the inverter's current upload signal and the frequency upload signal were incorrectly connected, it caused the operator to make an erroneous decision. When such a fault is encountered, only the current and current signals can be analyzed, and the frequency and rate signals can be uploaded. Change the situation, check the cable and loop number, and correct it after confirming it is correct; between the host computer and the inverter there is a signal transmission of the given amount and feedback amount. If these two quantities are reversed, the inverter cannot realize remote Operation, if you encounter such a fault, first find out the terminals of the given quantity and feedback signal from the terminal block, turn it on, and then use the active signal generator to add 4-20mA current signal to the circuit, if After the signal is added, the corresponding frequency can be displayed on the inverter, indicating that the loop is a given signal loop of the host computer to the inverter; if the signal is added to the upper machine, the corresponding frequency can be displayed, indicating that the loop is the upper inverter. Machine feedback loop signal.
IV. Concluding remarks With the continuous expansion of the application range of frequency converters, technicians are becoming more familiar with the frequency converters. The problems that occur during the use of frequency converters are roughly similar. The ACS510 series inverters used in the auxiliary network system of Ningxia Dam Power Generation Co., Ltd. are used. For example, the common faults of the inverter, the fault diagnosis displayed on the control panel of the inverter, and the common faults of the external circuit of the inverter are analyzed. The possible faults and general processing methods of the ACS510 series inverter in use are described. It is hoped that the technical personnel at the production site will be able to deal with the defects as soon as possible, and at the same time, it is for the reference of the industry insiders.
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