RX62T

Position Control of PMSM with Encoder

R01AN0899EU0200 Rev. 2.00

Page 2 of 22

Jan. 31, 2014

1. Overview

Position control plays an important role in various areas such as automation industry, semiconductor industry, etc.

Permanent magnet synchronous motors (PMSM) are ideal for advanced position control systems for their potentials of

high efficiency, high torque to current ratio, and low inertia, have been widely used in the industrial fields. Various

approaches have been made to realize high performance motion control.

With successively improving reliability and performance of digital controllers, advances in Microprocessors (MCU) have

greatly enhanced the potential of PMSM in servo position control applications. Digital control can be implemented by

MCUs, which make it superior to analog based stepper control, since the controller is much more compact, reliable, and

flexible. High performance of PMSM can be obtained by means of field oriented control, which is only realizable in a

digital based system.

RX62T is a 32-bit high-performance microcontroller with a maximum operating frequency of 100MHz and 165 DMIPS

and single precision floating-point unit (FPU), which is equipped with multifunction timers (

H

MTU

H

,

H

GPT

H

), high-speed

H

12-

bit A/D converter

H

and encoder signal capture for facilitating servo motion control.

In this application note, a RX62T floating point unit (FPU) based position motion control system is proposed. Position

regulation is developed to provide both a trajectory generator and a PID controller, which ensures accurate position

control and fast tracking. The trajectory generator provides position set-point commands. The position PID controller

operates on the position error and outputs a current command. The current regulation with field oriented control is

implemented to secure fast dynamic response.

Software developed is applicable to following devices and platforms.

 MCU: RX62T and RX62N

 Motor: three-phase permanent magnetic synchronous motors (PMSM)

 Platform: Renesas RX62T demo kit

 Control algorithm: Encoder based position control