Defining the System Plant

Last modified by Microchip on 2023/11/09 08:54

The system or plant block defines the information about the power supply hardware that needs to be controlled. Because Microchip dsPIC® Digital Signal Controllers (DSCs) are well suited for many different power supply topologies, the Digital Compensator Design Tool (DCDT) Graphical User Interface (GUI) gives you the flexibility to define the plant using any one of these three different methods:

  • Polynomial Transfer Function
  • Pole Zero Transfer Function
  • Import Plant Data

Select Plant Entry Method
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Plant in Polynomial Form

You can enter the transfer function of the system or plant by expressing this in a polynomial form, where you define each of the polynomial coefficients.

Polynomial Plant Transfer Function

Plant Polynomial Window

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Plant in Pole Zero Form

The second method to enter the system plant information is using the frequency domain real poles and real zeros by entering the frequency location (in Hz). The GUI will compute the system transfer function and use this for all computations.

Pole Zero Plant Transfer Function

Plant Pole Zero Window

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Plant Imported From

The third method to define the system plant is by importing the gain and phase information as a data index using a Comma Separated Value (.CSV) file format. This allows you to import the frequency response characteristics from real hardware measurements or data gathered using simulation tools.
The data to be imported must follow these formatting guidelines:

  • The file must be saved as Comma Separated Values (.CSV).
  • The first row will not be imported and is assumed to be the column name.
  • The first data column will be the frequency, defined in Hertz (Hz).
  • The second data column will be the Plant Gain magnitude, defined in decibels (dB).
  • The third data column will be the Plant Phase, defined in degrees (°).
  • For good plant resolution it is suggested to have at least 10 data points per frequency decade, there is a maximum plant.
  • The frequency sweep data must be sequential and incrementally organized.

Import Plant CSV Format Example

Using the File Browser Menu, locate the data file. Once the data is successfully imported, it will be displayed inside the GUI window, as shown in the accompanying image.

Import Plant Window

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