BEF 45101 (Power Electronics Lab.)

Development of PWM controlling the speed of the

BEF 45101 (Power Electronics Lab.)

PWM signal Using a Low cost Microcontroller

controlling the speed of the DC Motor

Microcontroller for

1.1 LEARNING OUTCOME

• to indentify the low cost microcontroller • to establish a communication between the microcontroller using

MATLAB-Simulink programming • to generate the basics Pulse Width Modulation pattern using MATLAB and the

microcontroller • to develop the gate driver that is suitable for triggering the MOSFET

1.2 THEORY

This lab is purposed to the student in order to understand the working principles of the operation of each converter that have been learnt during BEF34503, BEF38503 and BEF35603 subjects. The low cost microcontroller that will be used in this lab is the Arduino. As known, Arduino is one of the low cost microcontrollers that capable to be a digital signal processing device but with some limitation such as low switching frequency. The advantage of using Arduino is the capability to communicate with the MATLAB in order to generate a suitable signal that depends to the load. The basic MATLAB programming will be used for communication between the Adruino and the MATLAB. In this communication, there is no programming required or been developed where it just based on the function of the Simulink-Blocks with the Arduino Library that can be downloaded in the MATLAB webpage. This lab is the continuous works which is to develop the completed DC motor control using the MOSFET as the switching devices in open loop mode. In order to drive the MOSFET, a suitable gate driver is needed where, the active input must be in 15 V supply. As recorded, the Arduino is only generated 3.3 V output and that why the gate driver is necessary for the MOSFET operation.

.

1.3 EQUIPMENT LIST

Hardware : PC/Laptop DC motor DC-DC converter Microcontroller- Adruino

DC Supply Voltmeter Oscilloscope

Software :

Matlab Simulink 2010 or latest version Matlab Adruino Library

1.4 PROJECT TASKS

In this project, student is required to carry out a study on low cost microcontroller and to conduct a experiment test on controlling the DC motor control with open loop mode. At the end the student is able to adjust the speed of the dc motor by changing the PWM generation by adjusting the switching frequency period in the MATLAB-Simulink blocks. The MATLAB Arduino library is required to be used as a medium of the communication for the microcontroller. The block diagram of the project is given as in Figure 1.

At the end of this project the student/team should present their working project in poster and demonstration works for the evaluation that will be conducted by the Lab Assistant Engineer and the Lecturers. The presentation will be conducted in Week 14. The final report based on the lab module needs to be submitted 1 week before the presentation.

Figure 1 : Motor control block diagram

Question

1. Complete the table when the PWM duty cycle is been changed

V-in (volt) Duty cycle Pulse Width Modulation Pattern ( from oscilloscope)

Time (s)

12 20% 12 60% 12 80%

2. State the advantages of having different PWM signal for a converter? 3. What is the purposed of the Digital Output block in the MATLAB-Arduino library? 4. State two functions of the gate driver? 5. Determine the speed of the motor for 50% duty cycle if the dc input to the converter is changed to 20 Vdc 6. Complete the table below by using the oscilloscope for voltage output and the motor speed

V-in (volt) Duty cycle V-out (volt) (With oscilloscope)

Speed (rpm)

12 0.2 12 0.4 12 0.6 12 0.8 12 0.9

DC Motor

DC-DC

Buck

Converter

DSP/µC Adruino

DC Supply (5V)

t-on t-off T

REFERENCE

1. Lab Sheet BEF 45101 “ Appendix 1”

2. http://www.mathworks.com/hardware-support/arduino-simulink.html.

3. https://www.youtube.com/watch?v=_OLctOFjjYQ

4. Shamsul Aizam Zulkifli M. N. Hussin, Abdul Salam Saad, “MATLAB-Arduino as a Low Cost Microcontroller for 3 phase inverter” 2014 IEEE Student Conference on Research and Development (SCoRED), 16-17 Dis.2015, Penang, Malaysia.

5. Shamsul Aizam Zulkifli, Mohd Razali Tomari, Mohd Najib Hussin, Abdul. Salam. Saad, Mohd. Khair. Ab Ghani, Farih Deraman , Nawi Berahim, Abdul Hadi Abdullah, “Application of Robust Control on Arduino Microcontroller Testing in Power Electronics Converters”, Journal of Appiled Mechanics and Material, Vol 785, July 2015.

6. Shamsul Aizam Zulkifli, Suhairiyanti Mohd Yusof, Ahmad Husaini Hussian, Ahamd Izzat Mod Arifin, Mohd Saiful Najib Ismail@Marzuki, Wan Ahmad Khusairi Wan Chek and Faizul Rizal Mohamed Tazudin “MATLAB-SIMULINK Controller Design For Arduino Target on AC Motor Control Application, Inter. Jrn. Of Energy and Power Engineering Research, UMPEDAC.

7. Course subjects for BEF34503, BEF38503 and BEF35603

Appendix 1

PROCEDURE FOR MATLAB-SIMULINK ARDUINO COMMUNICATION :

(a) Install MATLAB 2010 or latest version (b) Write ‘targetinstaller in M-file window or Using Add on icon on the MATLAB (c) When the new window open click on the Arduino and follow the instruction (d) When it finished you can use the Arduino block diagram at Arduino library in

Simulink shows in Figure A1

Figure A1

(e) Create a simple block diagram using Adruino output block function given in the library. (f) Test the interfacing between Matlab and Arduino. (g) Connect the LED at the Arduino digital output and observe the LED output. (h) When step (g) was successful, the gate driver for the MOSFET needs to be build

by referring to Figure A2. (i) Test the gate driver using the oscilloscope depends to the input given in Figure

below

Figure A2(a): Gate driver circuit

Figure A2(b): Gate driver circuit

Second task

It is to design a buck converter that converts 12V to 0-12V and supply 1A to the Load based on Figure A3. The switching frequency needs to be approx. 2kHz generated from the Arduino. This switching frequency might be imposed to ensure that the dc/dc converter is not operating at the same frequency as other sensitive electronics in the circuit

As know our duty cycle is represented by,

From µC

PWM signal

To Mosfet

� =����

���

The L and C can be calculated based on the equation given,

And the C (Capacitor), where r =0.05%

Figure A3: Buck converter circuit

PROCEDURE FOR OUTPUT MEASUREMENT :

(a) Develop the buck converter with the given parameters (b) Changed the switch symbol to Mosfet which is shown in buck converter

circuit

V

in=12 V

M

IN4148

L

C R

RD)(

=LL

Lf

D)(

R

Lf

D)(

RVo

⋅−≥⇒

≥−−

≥

−−⇒

2f

1

02

11

02

11

min

2o

o

LCf

D)(=

V

∆V=r

8

1−

(c) Connect gate driver in Part A to the buck converter in this task (d) Download the Adruino program from the Matlab-Simulink to the Adruino

board (e) Connect Adruino, gate driver and buck converter and test the output in

open loop (f) Change the load with the DC motor and test the system (g) Change the PWM pattern from the PC in order to adjust the different

speed of the DC motor (h) The student can model the complete circuit outside the Lab hours but the

student needs to make an appointment with the Technical Assistant in the Lab.

Rating Excellent 5

Good 4

Fair 3

Poor 1

Very Poor

C2: Introduction

Summarized procedure and purpose of work with relevant background information are sufficiently provided and the report are very well organized.

Summarized procedure and purpose of work with relevant background information are available but not completely provided. The report still well organized.

Summarized procedure and purpose of work with relevant background information are missing. Report is still reasonable well organized.

Summarize procedure and purposes of work with relevant background information are missing. Report is poorly organized.

C3: Data Collection

and Recording

Data collected is clearly written and appropriately tabulated; Data is within the expected norms.

Data collected is improperly tabulated (units missing) or the data deviates appreciably from the expected norms.

Some data is missing and / or data deviates drastically from the expected norms.

Data is poorly organized or grossly incomplete

C4: Analysis (Calculations and Results)

All required calculations are present and performed correctly; Results (with % error where appropriate) are clearly stated.

All required calculations are present but minor errors are present in the calculations; Results section is incomplete (i.e. % error values are reported without the values they refer to).

Some calculations are missing and / or there are significant errors in the calculations.

Calculations are grossly incomplete and / or incorrect.

A3: Discussion/ conclusion

All assigned questions (if any) are answered and discussed

All assigned questions are answered and discussed lightly.

Some assigned questions are answered. Discussion on

All assigned questions are not answered Discussion on

appropriately. Discussion of results shows a strong grasp of the scientific concepts covered by the lab.

Discussion on results needs some refinement but shows a reasonably strong grasp of the scientific concepts covered by the lab.

results does not identify appropriate concepts, needs significant work and / or show a weak grasp of concepts.

results is inappropriate for the lab and shows a lack of comprehension of scientific concepts.