As use of incorrect or unreasonable environmental settings, will be easy for the Inverter failure and malfunction, or unable to meet the expected operational results. To take preventive measures, prior to the failure to seriously analyze the reasons for it is particularly important.
扰 The interference of external electromagnetic induction
If the inverter exist around the source of interference, they will be through radiation or power inverter line penetrated the internal control loop caused malfunction, resulting in not working properly or downtime, even when serious damage inverter. Improve the inverter's own anti-jamming capability is important, but due to the installation cost constraints, taken in external noise reduction measures to eliminate the source of interference is more reasonable and more necessary. The following measures are implemented to noise interference "three no's" principle of the specific ways: Inverter around all the relays, contact with the control coils on the need to prevent the installation of voltage shock absorption device, such as RC absorption; control as short as possible Circuit wiring distance, and its main lines and the separation line designated by shielding circuit, according to regulations, if more lines should be used reasonable relay; inverter ground terminal should be carried out, can not be welded , The ground force mix; inverter input noise filters installed to prevent the introduction of the power line into interference.
Installation of the environment
Inverter are electronic devices installed in their specifications are detailed in the installation of the use of environmental requirements. In exceptional circumstances, if it does not meet these requirements, must be kept to adopt corresponding measures to curb: the vibration caused by mechanical damage electronic devices the main reason for shock and vibration larger of the occasion, should be used, such as rubber anti-vibration measures humidity, corrosion Gas and dust, and other electronic devices will cause rust, connection is bad, insulation and reduce the formation of short-circuit, as a precautionary measure to cope with the control panel to deal with anti-corrosion protection against dust and a closed structure, temperature is affecting life and reliability of electronic devices of the Important factors, in particular semiconductor devices should be installed in accordance with the requirements of environmental conditions or install air-conditioning to avoid direct sunlight.
In addition to the above three points, periodic inspection inverter air filters and cooling fans are also very necessary. For special occasions, the Alpine, in order to prevent the microprocessor because the temperature is too low not work properly, space heaters should be set up to take the necessary measures.
Power abnormalities
Power Changbiaoxianwei various forms vary, but generally the following three kinds, namely lack of low-voltage power failure, and sometimes they also form the mixture. These anomalies most of the main transmission lines is due to wind, snow, lightning caused, sometimes because the same power supply system within the phase to short-circuit and short circuit. And because of geographical and seasonal lightning are very different. In addition to voltage fluctuation, some power network or on its own power generation units, will also appear frequency fluctuations, and these phenomena sometimes repeated in a short period of time in order to ensure the normal operation of equipment, the inverter power supply also made corresponding requirements.
If the direct vicinity of starter motors and Induction Cooker, and other equipment, in order to prevent such equipment at the lower voltage, and inverter power supply system separation, reducing the mutual impact of the requirements of instantaneous blackout could continue to run after the occasion , In addition to choose a suitable price of the inverter, but also because of the electrical load in advance to consider the ratio of Jiangsu. Inverter and external control loop compensation by instantaneous stop, back when the voltage, speed through the tracking and detection of motor gun to prevent the acceleration of the current, the amount required to be running the equipment, to the inverter The installation of automatic switching of the power blackout is not installed.
Diode input and control the use of single-phase power inverter, although the lack of state also will continue to work, but in individual rectifier current device too large capacitors and the pulse current is too large, long-term if the inverter will run the life and Adversely affect the reliability should be dealt with early detection.
Lightning, thunder and lightning sensors
Struck by lightning or a lightning sensors sometimes the impact of voltage inverter can also cause damage. In addition, when a power supply system side with a vacuum circuit breaker, short-circuit-switching can also have a high voltage shock. Transformer side of a vacuum circuit breaker disconnect, coupled through the secondary side in the formation of a high voltage shock peak.
To prevent the impact of voltage due to damage caused by over-voltage, usually need the input of the inverter and varistor absorbing devices, such as to ensure that input voltage inverter is not higher than during the main circuit to allow the maximum voltage. When using a vacuum circuit breakers, should be used as a shock absorber additional RC surge. If one side of a transformer vacuum circuit breakers, because of the timing control to ensure a vacuum circuit breaker action before the first inverter disconnect.
The last transistor inverter in the following shortcomings: easy trip, it is not easy to start, a low-load capacity. As IGBT CPU and the rapid development of inverter an increase of sound internal self-diagnosis and fault prevention features, substantially improve the reliability of the inverter.
If the use of vector control inverter in "all areas of automatic torque compensation", which "lack of start-up torque," "environmental conditions caused by changes in output decline" cause of the malfunction, will be good to overcome. This feature is the use of inverter within the micro-computer high-speed computing, calculated at the current needs of torque, rapid output voltage of the amendment and compensation to offset the result of external conditions caused by changes in output torque converter changes .
In addition, the inverter software development more complete, the inverter can be pre-set all kinds of internal measures to prevent failure, and failure to resolve after the operation can continue to maintain, for example: the free parking in the process of re-starting motor ; Automatically reset the internal fault and maintain continuous operation; excessive load torque can automatically adjust operating curve, to avoid Trip; mechanical systems can detect the abnormal torque.
Inverter on the impact of peripheral devices and failure to prevent
Inverter the installation will also have an impact on other equipment, sometimes even leading to other equipment failures. Therefore, the impact of these factors on the analysis and study what measures should be taken very necessary.
Power high harmonics
Since almost all of the inverter using PWM control methods, such a pulse modulation form makes inverter operation at the side of a high-power harmonic current and voltage waveform distortion caused by the power system have a serious impact, often use the following Treatment: The transformer for the inverter power supply, power supply systems and other separation in the inverter input side of the installation of filtering reactor or more rectifier bridge circuit, reducing the high harmonic components, for those that are into the phase capacitor Occasions because of high harmonic current capacitive current increase will cause severe fever, must be in before the series connection capacitance reactor, to reduce the harmonic component of the reactor, the induction of a reasonable basis, avoid a LC oscillation.
Motor temperature is too high and operation of the
For existing motor VVVF transformation, due to the cold in the low-speed motor running at a reduced ability to cool the overheated motor. In addition, because the inverter output waveform in containing the high harmonics is bound to increase the iron loss and motor loss of copper, confirmed the electrical load in the state and scope of operation, take the following measures: the motor-cold ventilation Or increase the electrical specifications grade; replacement for the electrical frequency; limit the scope of operation, avoiding low-speed zone.
Vibration, noise
Vibration is usually due to the pulse of motor torque and mechanical systems caused by the resonance, especially when the pulse of torque and mechanical resonance, exactly the same time much more serious. Noise is usually divided into frequency noise and electrical noise devices, the installation of different places to take different measures to deal with: inverter in the debugging process, to ensure accuracy of control under the premise should be to minimize torque pulse components; debugging confirmed Mechanical Resonance, the use of the frequency inverter shielding function, so that these resonant points excluded from the scope of the operation because of noise inverter main cooling fan, generate electrical and mechanical resistance, the choice of low-noise devices in the motor and inverter AC set up between the anti-rational, PWM modes decreased due to the high harmonics.
High-frequency switching to a peak voltage electrical insulation adverse
In the output voltage inverter, with high-frequency waves with peak voltage. These high-voltage harmonics will reduce the impact of the motor winding insulation strength, particularly in the PWM control of inverter more obvious, should take the following measures: as short as possible inverter to the wiring from the motor used to block the diode A surge absorption device, the output voltage inverter; the PWM Inverter should try to enter the motor side and filters.