15 Introduction

The PI controller is a widely used closed-loop controller for controlling a first-order system. The basic functionality of a PI controller is to make the feedback measurement to track the reference input. PI controller performs this action controls its output until the error between the reference and feedback signals becomes zero.

There are two components that contribute to the output: the proportional term and the integral term, as shown in the following figure. The proportional term depends only on the instantaneous value of the error signal, whereas the integral term depends on the present and previous values of an error.

Figure 15-1. PI Controller in Continuous Domain

PI controller in the continuous time domain is expressed as:

Where,

y (t) = PI controller output

e (t) = reference (t) - feedback (t) is the error between reference and feedback

To implement the PI controller in the digital domain, it has to be discretized. The discretized form of the PI controller based on zero order hold method is shown in the following figure.

Figure 15-2. PI Controller based on Zero Order Hold Method

Summary

Core VersionThis document applies to Speed ID IQ PI Controller v4.2.
Supported Device Families
  • PolarFire® SoC
  • PolarFire
  • RTG4™
  • IGLOO® 2
  • SmartFusion® 2
Supported Tool FlowRequires Libero® SoC v11.8 or later releases.
LicensingThe complete encrypted RTL code is provided for the core, enabling the core to be instantiated with SmartDesign. Simulation, Synthesis, and Layout can be performed with Libero software. The Speed ID IQ PI Controller is licensed with the encrypted RTL that must be purchased separately. For more information, see Speed ID IQ PI Controller.

Features

The Speed ID IQ PI Controller has the following key features:

  • Computes d-axis current, q-axis current, and motor speed
  • PI controller algorithm runs for one parameter at a time
  • Automatic anti-windup and initialization functions are included

Implementation of IP Core in Libero Design Suite

IP core must be installed to the IP Catalog of the Libero SoC software. This is done automatically through the IP Catalog update function in the Libero SoC software, or the IP core can be manually downloaded from the catalog. Once the IP core is installed in the Libero SoC software IP Catalog, the core can be configured, generated, and instantiated within the SmartDesign tool for inclusion in the Libero project list.