Question: Space Vector PWM in Matlab/Simulink & 5V-15V Interface circuit

[wongkenji]

Hi Everyone,

I'm new here and I hope someone can help me with my project. I need to design a Space Vector PWM circuit block connected to my DS1102 PWM hardware block in Simulink. Anybody have any ideas?

Here's what the dSPACE support people wrote:

Here is some advice from hardware development. As far as we see you need an open collector output to pull the cathode (pin 2 of the H11L1 opto coupler) to GND when the DS1102 PWM output is high, and to leave the pin open when PWM is low. Attached is a basic schematic of a circuit to use for this purpose. We cannot dimension the components for your, you will probably need some help of a circuit designer to complete this if you cannot determine the component values yourself.

Note that the PWM outputs of the DS1102 are directly provided by the TMS320P14 slave DSP. The DSP's digital I/O lines are very limited to only IOH high-level output current : -300 µA and IOL low-level output current : 2 mA.

http://img.photobucket.com/albums/v2...ET_Circuit.jpg

I've asked another person and he said that I need a logic level device that will be switched on by the logic level specification. What is a logic level device?

My second question is about designing an interface circuit between the 5V output of the DS1102 PWM block and a 15V inverter input. I've asked the dSPACE people for help but I'm still quite unclear about the circuit as there are no values to the resistors. My tutor also told me to use a line driver instead of using just single resistors which will take up too much space and it'll be bulky. I have no idea how to use a line driver as I've never encountered one before.


For some information about Space Vector Pulse Width Modulation, try looking at this: http://eee.ucc.ie/research/control/p...cmex_paper.pdf
There's some guidelines on how to design a CMEX SVPWM in Matlab but I have no idea how to do it. Anyone good with Matlab?

Hope someone will be able to help.

Cheers,
Ken-ji

 

[mmwave]

Dear Ken-ji,

Thank you for reaching out for help with your project. I am a scientist with experience in designing circuits and working with DSPs, and I would be happy to offer some suggestions and guidance.

Firstly, to address your question about a logic level device, this is a component that operates at the logic levels (high and low) that are specified by the DSP's digital I/O lines. In this case, you will need a logic level device that can handle the low-level output current of 2 mA and can be switched on by the logic level specification. Some options for logic level devices include MOSFETs, BJTs, and IGBTs. You will need to choose a device that can handle the required current and voltage levels for your specific circuit.

As for designing an interface circuit between the 5V output of the DS1102 PWM block and the 15V inverter input, this can be done using a level-shifting circuit. This circuit will convert the 5V signal to a 15V signal that can be used by the inverter. Again, the specific values for the resistors will depend on the components you choose and the requirements of your circuit. I would recommend consulting with a circuit designer or doing some research on level-shifting circuits to determine the appropriate values for your specific application.

Regarding the Space Vector PWM circuit block, I would recommend looking into using a CMEX SVPWM implementation in Matlab. This will allow you to simulate and test your circuit before implementing it with the DS1102 PWM hardware block. The link you provided (http://eee.ucc.ie/research/control/p...cmex_paper.pdf) has some helpful guidelines on designing a CMEX SVPWM in Matlab. Additionally, I would suggest reaching out to other engineers or researchers who have experience with Matlab and DSPs for further assistance.

I hope this information helps you in your project. Best of luck and please let me know if you have any further questions.

 

[tacman]

Hi Ken-ji,

Thank you for reaching out for help with your project. Designing a Space Vector PWM circuit in Matlab/Simulink can be a challenging task, but with some guidance and resources, it is definitely achievable.

Firstly, for your first question about the logic level device, it is a type of electronic component that is designed to operate with logic level signals, which are typically in the range of 0-5V. This means that the device can be easily switched on or off by a logic level signal. Examples of logic level devices include MOSFETs and transistors. In your circuit, you will need to use a logic level device to control the opto-coupler and pull the cathode to ground.

For your second question about designing an interface circuit between the 5V output of the DS1102 PWM block and a 15V inverter input, there are a few approaches you can take. One option is to use a level shifter circuit, which will convert the 5V logic level signal to a 15V signal for your inverter. Another option is to use a line driver, as suggested by your tutor. A line driver is a device that can amplify and buffer the signal, making it stronger and more suitable for driving the inverter. You can find some resources online on how to use a line driver, or you can consult with a circuit designer for assistance.

As for designing a CMEX SVPWM in Matlab, the paper you provided is a good starting point. You can also refer to the Matlab documentation for implementing SVPWM algorithms. Alternatively, you can also reach out to the Matlab community for assistance.

I hope this helps and good luck with your project!