Rockwell Automation Publication 750-AT006D-EN-P - January 2022 7
Chapter 1
Background
This document is intended to assist PowerFlex® 755T drive users in tuning Flux Vector position and velocity loops, filters, and other features
to achieve high performance. Here, the primary control mode is “Induction FV". The information is intended for users who are familiar with
the following:
• PowerFlex 755T drive connectivity and configuration
• Drive communication through a personal computer or human interface module (HIM)
• Use of Connected Components Workbench™ (CCW) software
• Understanding how control loops work in drive applications
Parameters are referenced as Port Number:Parameter Number [Parameter Name]. For example:
10:900 [Motor Inertia] denotes port 10:parameter number 900 named Motor Inertia.
0:65 [Pri MtrCtrl Mode] denotes port 0:parameter number 65 named Pri MtrCtrl Mode.
Quick Start Guide—See Recommended Default Settings
on page 58.
Mechanical Loading
To effectively control the motion of a mechanical system and achieve high performance, first understand the mechanical properties of the
system that dictate performance. This section describes these mechanical properties, how they limit performance, and what tuning features
apply to compensate for them. The best approach is to build a mechanical system that is as rigid as possible and with a constant inertia, but
that is not always possible or cost-effective. This section includes:
• Inertia
• Compliance on page 9
• Backlash on page 11
• Resonances on page 12
Inertia
With rotary motors and rotating machinery, inertia is rotating mass. An object with mass requires a certain amount of torque to accelerate
and decelerate it at a specified rate. The larger an object is, the more torque is required. As a result, inertia affects how large of a drive and
motor is required which ultimately affects drive tuning. A few things happen as inertia increases:
• More torque is required to accelerate the inertia to a given speed.
• Or it takes longer to accelerate the inertia to a given speed with a fixed torque.
• Adverse effects of non-rigid components (compliance and back lash) are amplified, making it more difficult to tune.
A motor with a connected load is shown in Figure 1
as a simple two mass system.
To Next Page
Loading...
Need help?
General
