Modeling Motor Drives with Long Cables and Their High Frequency Phenomena.
Driving an electric motor with long cables from an inverter will introduce ringing and oscillations on the drive waveforms from which large over-voltages could result.
” Will these over-voltages harm the power devices or the motor?”
” How can this system be modeled?”
” Is it possible to mitigate and reduce the impact?”
In this webinar we will answer these questions and demonstrate how several new features of PSIM v12 help us to overcome the issues that high frequency phenomena can cause.
With PSIM v12 several new models were included to look at this issue. There are three main parts to the system each required a specific model:
- AC cable model
- Machine model with high frequency input impedance
- Switch model
Some background information in preparation for the webinar:
The new AC cable model allows the designer to select how many discrete sections the cable should be defined with. The distributed model allows for better definition of the high frequency interactions.
With other tools however, modeling very small inductance and capacitance values can be very difficult as it will introduce very stiff equations causing convergence issues. With PSIM on the other hand these types of equations do not cause convergence issues whatsoever.
Also added in v12 was an induction machine which allows for the high frequency input impedance to be defined. This input impedance is important as it provides the proper termination impedance for the cable model which will be the source of reflections back down the cable to the inverter.
Having added non-ideal switch models since PSIM v10, PSIM now supports a full range of non-ideal switches: IGBT, MOSFET, WBG (SiC & GaN), and diodes with reverse recovery. The type of switch you use will impact the turn on speed, a faster turn on speed with introduce a sharper edge to the cable which in turn has more high frequency components which could cause more problems than a slower device.