ECE 4600 Project Proposal

Group 12

Wireless Firing Interface for Power Electronic Converters

Authors: Supervisors:

Brennan Martin Dr. Ani Gole

Luchen Song Cyrus Shafai

Jason Gole

Meng Wang

Date of Submission:

Sept 27, 2013

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Contents

1. Introduction………………………………………………………………………………………...1

2. Project Specifications………………………………………………………………………………2

2.1 Wireless Specifications……………………………………………………………………......2

2.2 Control Board Specifications….………………………………………………………………4

2.3 Converter Specifications………………………………………………………………………5

3. Milestones………………………………………………………………………………………….6

4. Gantt Chart…………………………………………………………………………………………7

5. Budget……………………………………………………………………………………………...8

6. References………………………………………………………………………………………….9

List of Tables

Table 1-Wireless specifications

Table 2-Controller specifications

Table 3-Converter specifications

Table 4-Milestones/task distribution

Table 5-Proposed budget

List of Figures

Figure 1: Proposed system topology

Figure 2: ZigBee wireless network

Figure 3: Chopper circuit with DC motor load

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1. Introduction

Power Electronic (PE) converters are a family of devices used to convert electricity from one

form to another. Encompassing a variety of DC-DC, DC-AC, and AC-AC devices, all modern PE

converters rely on the rapid switching of semiconductor devices to function. However, PE converters are

not capable of generating their own control signals, necessitating the installation of either a hardwired

control board, or a wired control system capable of transmitting them. However, both methods pose

problems. Hardwired boards are small, cost effective and easily installed, but can only give a single

output. Changing the output of the system would require a new board. On the other hand, wired systems

give operators control and allow easy monitoring, but are expensive, and also require fiber-optic cables if

the system is to remain electrically isolated. A wireless system would simultaneously be small,

controllable, and electrically isolated.

The goal of this project is to design and implement a wireless system that is capable of

controlling a basic DC-DC PE converter. The system will accept user input on a PC based interface,

transmit data to a control board connected to the converter, and allow a variety of DC outputs from the

converter. To allow wireless control of the system, we will be utilizing the ZigBee wireless protocol.

ZigBee offers a simple, reliable transmission protocol which is designed for low power usage, whilst

giving access to a multitude of integrated transmitter/microcontroller (µC) units.

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2. Project Specifications

The project will be broken down into 4 primary components:

A PC based user interface

A Wireless ZigBee based transmitter/receiver system

An IGBT (Insulated Gate Bipolar Transistor) driver board

A DC-DC PE converter

Figure 1: Proposed system topology

Figure 1 gives an overview of the entire system. The user interface on a pc will allow the user to

make changes to input control signals for the converter. The signal is then sent to out of the transmitter

and picked up by the receiver. The receiver sends the signal to the IGBT driver, which controls the

converter using the acquired signal. The output of the converter can then be used to power a load.

2.1 Wireless Specifications

We will be using the ZigBee wireless protocol to send data from the user to the IGBT driver.

ZigBee operates according to IEEE standard 802.15.4. The ZigBee protocol will allow us a wireless range

of 10 to 100 meters [1]. Testing will need to be done to determine the exact range.

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ZigBee allows one coordinator to send data out to one or more routers or end devices, as can be

seen in Figure 2. The routers can then send data further to more routers or end devices. The use of

multiple routers allows the signal to be relayed from one coordinator to several routers before reaching

the desired end device, increasing the maximum range of the system. For the purposes of this project,

only one coordinator and one end device will be used, with no intermediate routers.

Figure 2: ZigBee wireless network [2]

To communicate between the user and the IGBT driver, both a transmitter and a receiver are

needed. The transmitter will be the coordinator node, while the receiver will be the only end device. The

ZigBee module used will contain a built in antennae, as well as a microcontroller. Having built in

components will reduce the complexity of the design and will allow us to use two identical ZigBee

modules for both transmitter and receiver.

Using the ZigBee protocol for our wireless communication will allow us to use a single 9 volt

battery to power the microcontrollers. The use of a single battery is possible because the ZigBee wireless

protocol uses very little power, especially when compared to other wireless standards such as Wi-Fi or

Bluetooth. Other wireless standards have the advantage of transmitting data faster than ZigBee, but for

the purposes of this project low power consumption is more important than speed of transmission.

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The user interface will allow the duty cycle of the transmitted signal to be modified. The

microprocessor within the receiver will send the signal to the IGBT driver with a frequency of 2 to 5

kilohertz. The exact value will be determined when tests concerning the losses and smoothness of the

waveform have been conducted.

Table 1-Wireless specifications

Description Specification

Wireless standard ZigBee (IEEE standard 802.15.4)

Power Source 9 V

Wireless range 10-100m

Number of microcontrollers 2

Switching frequency 2-5 KHz

2.2 Control Board Specifications

As a microcontroller cannot safely supply a sufficient amount of power to switch on an IGBT, we

require a controller board to interpose between the microcontroller and the converter. The controller

board must accept an input signal that can be safely generated by a low power microcontroller, output

enough current and voltage to switch an IGBT, and accept a supply voltage that can be provided by a

battery. Desirable but nonessential characteristics include low delay time, low power usage, and the

presence of a low power or standby mode.

Table 2-Control Board Specifications

Description Specification

Supply Voltage 6-12 V

Input Voltage 2-5 V

Input Current .1-.5 mA

Output Current .25-1 A

Delay Time 5 µS

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2.3 Converter Specifications

The DC-DC converter we are planning to use is called a chopper. The chopper is controlled by an

IGBT power electronic switch. The IGBT is repeatedly switched on and off by a voltage pulse. The

on time per voltage cycle can be controlled by controlling the on/off time ratio of IGBT, called the

duty cycle. If the on time is D, and the IGBT is switched on/off during period T, then the off time is

(1-D)*T. The average voltage output [3] is then:

[

]

For the purposes of this project, we want to select a voltage that is high enough to be stepped

down to a useful level, but still low enough that we do not need to use high voltage equipment. We

also want enough power output to do useful work with the output, such as driving a DC motor.

Table 3-Converter specifications

Description Specification

Input voltage 28 V

Output voltage 12 – 24 V

Output current 5 A

Switching frequency 2 -5 kHz

Figure 3: Chopper circuit with DC motor load [4]

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3. Milestones

Table 3 contains a list of project milestones and tasks, as well as the group members in charge of

completing them. A number of administrative tasks are absent from this list, but are listed in the

Gantt chart.

Table 4-Milestones/task distribution

Milestones and Tasks Individuals in charge

Research ZigBee communications Jason & Luchen

Coding language for µCs Jason & Luchen

DC-DC converter Meng

Design Design receiver PCB Jason

Design transmitter PCB Luchen

Code implementation Jason & Luchen

DC-DC converter Meng

IGBT driver Meng & Brennan

Simulation Test receiver design Jason

Test transmitter design Luchen

DC-DC converter Meng

Build Build receiver PCB Jason

Build transmitter PCB Luchen

Code µCs Jason & Luchen

Connect µC to IGBT driver Brennan

Connect µC to ZigBee transmitter Brennan

DC-DC converter circuit Meng & Brennan

Testing Wireless communication Jason & Luchen

DC-DC converter circuit Meng & Brennan

Implementation and final test Converter control with ZigBee Group

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4. Gantt Chart

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5. Budget

Table 4 contains a list of required components for our design, as well as associated costs. The

costs of shipping and taxes are included in the cost of each component. Our final cost is well

below the $400 maximum cost of the project. This gives us $150 to be used for unforeseen costs,

such as burnt out parts.

Table 5-Proposed Budget

Required part Number of parts Cost of parts

ZigBee module 2 $80.00

9 volt battery 2 $15.00

PCB 2 $100.00

Passive components TBD $25.00

IGBT 2 $10.00

IGBT driver 1 $5.00

MISC components TBD $15.00

Total $250.00

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6. References

[1] ZigBee Alliance (2013) Specification FAQ [Online] Available: http://www.zigbee.org [Sep. 26, 2013]

[2]RF Wireless World (2013) ZigBee Tutorial [Online] Available: http://www.rfwireless-

world.com/Tutorials/Zigbee_tutorial.html [Sep. 26, 2013]

[3]Mohan, Undeland, Riobbins, Power Electronics, 3rd

Edition. Hoboken: Wiley, 2002.

[4] Pedro Daniel Dinis Teodoro, “Development of a simulation environment of an entertainment

humanoid robot”, MS Thesis, Dept. Mech. Eng., Instituto Superior Technico, Lisbon, Portugal, 2007.