Technical Report



 
 
 
CONTROL OF PERMANENT MAGNET MACHINE USING TI-TMS320F240
 
Geeta Dhananjay Athalye
Ali Keyhani
 
The Ohio State University
Electrical Engineering Department
Columbus Ohio 43210
Tel: 614-292-4430
Fax: 614-292-7596
Keyhani.1@osu.edu
June 2000

 ABSTRACT:This report describes the design and implementation of an experimental setup for Field Oriented Control (FOC) of permanent magnet machine based on a DSP (Digital Signal Processor) system manufactured by Texas Instruments. The DSP system integrates into a single board the computational power of a TMS320F240 DSP with extra peripherals needed in vector control application, and therefore requires minimal hardware development. The control algorithm implemented is the discrete time sliding mode control. Simulation and Experimental results are presented. A technique for position sensorless control is also discussed in this report.

Control of brushless PM machines using the vector control techniques is becoming more popular. Due to the wide availability of high-speed digital signal processors, the need for extensive calculations no longer poses a hurdle in the FOC implementation. Now-a-days, digital signal processors with instruction cycles in the range of tens of nanoseconds are common. In order to implement FOC control of a permanent magnet machine, certain interface peripherals must be specifically built into the DSP system. These peripherals include analog to digital converters for feedback signal acquisition, a set of timers for PWM generation, a speed encoder interface, and digital to analog converters for tracing of signals. Previously, the time and effort in FOC implementation was greatly increased because all the peripherals had to be compiled. Therefore, a single board that would integrate the DSP with all the above-mentioned peripherals is highly desirable. One such board is currently available from Texas Instruments. This board, which is based on the Texas Instruments TMS320F240 DSP, contains all the peripherals mentioned above. This thesis describes the development of the FOC using this type of system.

Modern techniques propose the use of the continuous time sliding mode (CTSM) control for PM machines. Theoretically, this control has the advantages of ease of implementation, robustness to parameter variation and good dynamic response. However, some deterioration in microprocessor-based implementation is observed due to the limitation of the maximum sampling time, which in turn limits the minimum-switching interval of the sliding mode controller. This problem can be solved by employing a discrete time Sliding mode (DTSM) controller in conjunction with hardware PWM as discussed in this study.

In order to implement the vector control of PM machine the sensing of rotor position is of utmost importance. Speed transducers such as shaft-mounted incremental encoders or resolvers are commonly used for this purpose. These however have several limitations in terms of mounting, maintenance, aging and power consumption. This has led researchers to seek ways of implementing vector control without speed sensors or "sensorless control". One technique for sensorless control of brushless permanent magnet machine has been discussed in this report.This report describes the design and implementation of an experimental setup for Field Oriented Control (FOC) of permanent magnet machine based on a DSP (Digital Signal Processor) system manufactured by Texas Instruments. The DSP system integrates into a single board the computational power of a TMS320F240 DSP with extra peripherals needed in vector control application, and therefore requires minimal hardware development. The control algorithm implemented is the discrete time sliding mode control. Simulation and Experimental results are presented. A technique for position sensorless control is also discussed in this report.

Control of brushless PM machines using the vector control techniques is becoming more popular. Due to the wide availability of high-speed digital signal processors, the need for extensive calculations no longer poses a hurdle in the FOC implementation. Now-a-days, digital signal processors with instruction cycles in the range of tens of nanoseconds are common. In order to implement FOC control of a permanent magnet machine, certain interface peripherals must be specifically built into the DSP system. These peripherals include analog to digital converters for feedback signal acquisition, a set of timers for PWM generation, a speed encoder interface, and digital to analog converters for tracing of signals. Previously, the time and effort in FOC implementation was greatly increased because all the peripherals had to be compiled. Therefore, a single board that would integrate the DSP with all the above-mentioned peripherals is highly desirable. One such board is currently available from Texas Instruments. This board, which is based on the Texas Instruments TMS320F240 DSP, contains all the peripherals mentioned above. This thesis describes the development of the FOC using this type of system.Modern techniques propose the use of the continuous time sliding mode (CTSM) control for PM machines. Theoretically, this control has the advantages of ease of implementation, robustness to parameter variation and good dynamic response. However, some deterioration in microprocessor-based implementation is observed due to the limitation of the maximum sampling time, which in turn limits the minimum-switching interval of the sliding mode controller. This problem can be solved by employing a discrete time Sliding mode (DTSM) controller in conjunction with hardware PWM as discussed in this study. In order to implement the vector control of PM machine the sensing of rotor position is of utmost importance. Speed transducers such as shaft-mounted incremental encoders or resolvers are commonly used for this purpose. These however have several limitations in terms of mounting, maintenance, aging and power consumption. This has led researchers to seek ways of implementing vector control without speed sensors or "sensorless control". One technique for sensorless control of brushless permanent magnet machine has been discussed in this report.

The report has 119 pages.
 

 

If your company is a member of the Mechatronic Laboratory, please send the request to receive a copy of any technical report. If you are not a member please send a request to Ali Keyhani, Department of Electrical Engineering, Mechatronics Program at the following address: Ali Keyhani, Ohio State University, Electrical Engineering Department, Mechatronics Systems Laboratory, 2015 Neil Ave., 205 Dereese Lab., Columbus, OH 43210.

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