Ingenieurbüro für EMV

Dipl.-Ing. Heinz Lindenberger

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Models

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Saturation-ckt

Simulation of Saturation with CM-Cores

In this simulation, two Common-Mode Cores (CM) are shown - the left model has a purely linear behavior, while the right model simulates the saturation behavior of a nanocrystalline material


Both cores also show an equal frequency behavior, which was also modeled to be similar to nanocrystalline material

The diagram shows the current over time - blue for the Linear CM-Core - red for the Non-Linear-CM core


Defining the start of saturation at 10% deviation from the linear behavior, the saturation current here is just over 1 A

PWR-90uH-V-250V

Inverter simulation with Linear CM-Core inside the HV-Filter


0% is set as modulation (zero vector) - this results in the highest CM currents through the magnet core

Inverter simulation with Non-Linear CM-Core inside the HV-Filter


Apart from the magnetic core, the circuit is unchanged

PWR-90uH-V-250V-I-Cy

Current spikes through one Y-Capacitor (Cy1)                     The CM current through the magnet core is the sum of both Y-C

Saturation
PWR-90uH-1-V-250V
PWR-90uH-1-V-250V-I-Cy
PWR-90uH-V-500V-I-Cy

Current spikes through one Y-Capacitor (Cy1)          Doubling the battery voltage, doubles the amplitude of the current spikes        

Current spikes through a Y-Capacitor (Cy1)             With the Non-Linear Core, the current spikes have increased by about 30%


That's about the maximum current for the non-linear core - with barely acceptable inductance reduction

PWR-90uH-1-V-500V-I-Cy

At twice the battery voltage, the amplitude of the current spikes increases by a factor of 10 with the Non-Linear Core


The current spikes have now increased dramatically          

PWR-90uH-V-250V-LISN

Voltage spikes at the Artificial Network (BNN = LISN) with 250 V battery voltage and Linear Magnetic Core          

PWR-90uH-1-V-250V-LISN

Voltage spikes at the Artificial Network (BNN = LISN) with 250 V battery voltage and Non-Linear Magnetic Core              

PWR-90uH-V-500V-LISN

Voltage spikes at the Artificial Network (BNN = LISN) with 500 V battery voltage and Linear Magnet Core                

PWR-90uH-1-V-500V-LISN

Voltage spikes at the Artificial Network (BNN = LISN) with 500 V battery voltage and Non-Linear Magnet Core              

FFT-lin-250V
FFT-non-lin-250V

Noise level at BNN (=LISN)     250 V      Linear Magnet Core    

Noise level at BNN (=LISN)     250 V      Non-Linear Magnet Core  

FFT-lin-500V

Noise level at BNN (=LISN)     500 V      Linear Magnet Core  

FFT-non-lin-500V

Noise level at BNN (=LISN)     500 V      Non-Linear Magnet Core  

Results at the Artificial Network (BNN = LISN):          

Conclusion


With the models shown here, CM-Cores and CM-Chokes can be fully mapped in all relevant properties - both with the desired Frequency Characteristics, as well as with the desired Saturation Behavior


Thus, e.g. HV-Filters can be designed and tested to the limit of their ampacity - and beyond, e.g. to investigate the consequences in case of failure



     

 

At 250 V, the noise spectrum with the non-linear magnetic core is only slightly different than with the linear core. The deviation from the linear behavior is only 30%.

At 500 V, however, the noise spectrum with the non-linear magnetic core is significantly different than with the linear core. The deviation from the linear behavior is here about factor 10.

© Ingenieurbüro Lindenberger       8447