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I have used Microchip and TMS320 to develop VFD for various applications. To give you a top level view, The TMS320 is a high end solution - a lot of commercial variable frequency drive uses TMS320 DSP. Quite a bit of work in programming, but if you go to the Ti web site and look at their new InstaspinFOC and InstaspinMotion, Ti have the entire motor control solution software implemented in ROM, you buy the chip, write a C program to call up their motor control function and you and a VFD.
I have a problem with ABB ACS800-104-0105-3 drive model, the output current reading on the VFD is always double the reading of the clamp ampere(i.e. drive reading= 40 A, clamp ampere reading=20 A), what is the procedure that i can follow to detect the cause of this error?
If there is frequent current-limitation or overcurrent alarm during the variable speed drive running, we should check the loads and inverter IGBT module is normal or not, if its good, then the failure is the Hall magnetic compensation current sensor damaged on the control circuit of the variable speed drive. Hall magnetic compensation current sensor is a device to measure the current value of sinusoidal and non-sinusoidal periodic, which can truly reflect the real current waveform, to provide a control and protection signal to the variable speed drive.
It will cause a series problems during AC drive operation in various environmental conditions, take an example as: when failure occurs, AC drives protective function is activated, and the AC drive tripped immediately, the electric motor stop slowly, the red LED alarm indication turns on, the display panel shows alarm message code or fault content. Then we can analyze the variable frequency AC drive fault reasons base on the display information, if it is soft failures, we can cut of the AC drive and reset it.
In inverter regular inspection, we must cut off power before operation. Wait 4minutes (the bigger the longer, the maximum waiting time is 15 minutes) till the frequency inverter display panel LED indicator lights turn off, to make the main circuit DC filter capacitor fully discharged, and measure with a multimeter to confirm before proceeding.
Due to variable frequency drive can adapt to various requirements in production process, especially in the industrial automation control applications, AC variable frequency control technology has risen to be the mainstream in industrial automation controls. AC variable speed system performance is almost same as DC speed control system, even exceed the DC speed control system. It adopts all-digital control ways to enhance information processing capabilities greatly.
Transistor frequency inverter has the following disadvantages: easy trip, difficult re-start, poor overload capacity. As the rapid development of IGBT and CPU, the inverter drive integrates perfect self-diagnosis and fault prevention features, improve the reliability greatly.
Sometimes, lightning or lightning impulse voltage also will cause the variable frequency drive damaged. In addition, if the power supply system with a vacuum circuit breaker, short-circuit on/off will generate higher impact voltage. To avoid surge voltage causes overvoltage damaged, the general method is add varistor absorption on the variable frequency drive input side, and the vacuum circuit breakers should add RC surge absorber.
Variable frequency drive power anomalies can be divided into following three types: phase loss, low voltage and power off, sometimes they maybe appear mixed. The main reasons for these anomalies are transmission line impact by wind, snow and lightning, sometimes it's the power supply system appear ground wire and phase short circuit.
Variable frequency drives are electronic devices, they have stringent requirements in installation environment which is specified in its user manual normally. In exceptional circumstances, if it does not meet these requirements, we must adopt appropriate suppression measures: vibration is the main reason to cause electronic devices mechanical damaged, for big shock and vibration occasions, we should use rubber anti-vibration measures.
If there are interference sources around the variable frequency drive, they will invade into the VFD by radiation or power cable, to cause the control circuit malfunction, and result in machine not work or shut down, even cause the VFD damaged. The specific method to reduce noise interference: Install anti-surge voltage absorption devices to the wirings of relays and contactors around variable frequency drive, such as RC surge absorber.
Variable frequency drive cooling system mainly includes heat sinks and cooling fans, wherein the cooling fan service life is short. The fan generates vibration, noise increases and finally stops when approaching end-life, then the VFD drive tipped in IPM overheat.
Gozuk Service Gozuk Blog: all about electric motor control & drives industries development in energy saving applications.


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