Technical support and model request for Speedgoat's Baseline Real-Time Target Machines

Dear all,

I am interested in real-time target machines, here I would like to ask some questions and request some specific solutions.

I want to use the baseline real-time target machine of the I/O397 board to achieve the following functions:

1. Real controller, closed-loop control of simulink motor model in real-time target machines.

2. The PWM output by the real controller is 10kHz.

Problems I'm having:

First, use PWM Capture under FPGA resources to collect PWM. Then, I run the average value inverter and the surface mount permanent magnet synchronous motor simulink model in the CPU, PWM Capture gives the average value inverter model three duty cycle information, the inverter outputs three AC power, drives the permanent magnet Synchronous motor simulink model.

Observation found that the speed of the simulink model of the permanent magnet synchronous motor ran away or was unstable. I don't know what may be the cause.

Hope you can predict some possible influencing factors.

Help I hope to get:

Considering the cost, I hope to purchase the I/O397 baseline later, which means that the inverter and permanent magnet synchronous motor models can only run in the CPU.

Because the CPU of the baseline of the I/O397 board can only run the simulink model with a fixed step size of 20kHz.

So, I would like to request a simulink model of the inverter and PMSM that can run more accurately at a fixed step size of 20kHz.

I would very much like to get a reference model, which is very important to me. Here, I would be very grateful if you would provide such an inverter and PMSM model.

thank you very much.

XY

Answer 1

[Dimitri MANKOV]

Hi Xueying,

It's hard to say for sure based only on the information that you shared, but the time-drifting that you observed may be due to a lack of synchronisation between your model and the PWM signal used as an input to the model. In Simulink Real-Time, you could use an "Interrupt Setup" block to achieve this functionality.

Speedgoat real-time target machines are not limited to a fixed step size of 20kHz: in fact, the achievable freqency will depend on a multitude of factors, from the complexity of your model and the I/O interfaces required by your algorithm to the CPU and target machine type used. As a rule of thumb, you can achieve closed-loop rates between 1kHz and 20-40kHz for models using the CPU. This is typically not sufficient to sample PWM signals fast enough to get a good resolution, which is why this part of the algorithm is usually outsourced to an FPGA, like the IO397 module.

You can find an Electric Motor Control reference application here. I belive it would be a good starting point for your evaluation.

Best,

Dimitri

[Xueying Ma]

Hi,Dimitri,

Sincerely thank you for your answer, I benefited a lot from it.

due to experimental conditions. In about a month, I'll be experimenting again, and if there are any other questions, can I still ask you here?

Thanks again for your generosity.

Best,

Xueying