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Increase the power of my PWM output

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sridharvdp

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Hi,

I am trying to drive a BLDC Motor and the motor's ratings are 120W and 24V. For this I have made a 3 phase MOSFET inverter circuit with NEC 2SK3115 MOSFETs.
I have tried producing PWM signals using a DSP kit and the output amplitude of the PWM from the kit is not more than 2.4V. This is not sufficient for the MOSFETs to turn ON, so there has to be an additional power amplifier used to improve the power so that the signal can turn the MOSFET ON and drive the motor.
Can anybody tell me how do i increase the amplitude of the PWM?? or if there is any better way i can do to drive my motor?
Any suggestion could be of great help.

Datasheet of the MOSFET used in the inverter: https://pdf1.alldatasheet.com/datasheet-pdf/view/108847/NEC/2SK3115/+00J859VlDwa-uMNBtw+/datasheet.pdf

Thankyou
 

You can check what is the maximum duty cycle configured at source code.
Also, you can observe if frequency output is the same as at original Kit version ( ...presuming you already did some changes ).



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andre_teprom said:
You can check what is the maximum duty cycle configured at source code.
Also, you can observe if frequency output is the same as at original Kit version ( ...presuming you already did some changes ).



+++
Click to expand...

Can you tell me what does duty cycle got to do anything with increasing the amplitude here ? Can we use a inverted Schmitt circuit as a buffer to do it ?
 

If I understood correctly, despite not mentioned above, due control is based on a DSP platform, probably you are dealing with a sinusoidal output inverter, and in order to achieve that, a look-up table stores values scaled on sinusoidal pattern.

What happens is that Duty cycle duration is directly proportional to charging on output capacitor. It means that output maximum voltage is defined for maximum Duty cycle value.



+++
 

andre_teprom said:
If I understood correctly, despite not mentioned above, due control is based on a DSP platform, probably you are dealing with a sinusoidal output inverter, and in order to achieve that, a look-up table stores values scaled on sinusoidal pattern.

What happens is that Duty cycle duration is directly proportional to charging on output capacitor. It means that output maximum voltage is defined for maximum Duty cycle value.



+++
Click to expand...

I am not getting a sinusoidal output at any stage.. All i have done is porgramming a DSP using Matlab to produce 6 PWM Square waves which are then give to an inverter where the 6 PWM outputs are connected to each gate of the MOSFETs and all its trying to do is drive a 3phase BLDC. So at any given instant of time the output of the three phases connected to the BLDC will be having +DC at one phase,-DC at another and 0 at the third one. these three phases can take only these 3 values.
 

At this point, unless you provide more informations such as schematic and code program, will be a little hard provide a more accurate help.


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