hbridge

“H-BRIDGE QUAD MOSFET DRIVER

FOR DC MOTOR CONTROL”

Submitted by

Ritesh Kakkar

2011-12

DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING

SHIVALIK COLLEGE OF ENGINEERING

DEHRADUN (UTTARAKHAND)-248001

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Acknowledgement

A special thanks to Mr.Rohan Raj of the Department of

Electrical & Electronics Engineering for his support and guidance

throughout the Project preparation. Also, special thanks to

Er.A.K.Gupta, Head of Department, Department of Electrical &

Electronics Engineering for supporting our endeavor .

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I. Introduction

An H-Bridge is an electronic power circuit that allows motor

speed and direction to be controlled. Often motors are controlled from

some kind of ”brain” or micro controller to accomplish a mechanical

goal. The micro controller provides the instructions to the motors, but

it cannot provide the power required to drive the motors.

An H-bridge circuit inputs the micro controller instructions and

amplifies them to drive a mechanical motor. This process is similar to

how the human body generates mechanical movement; the brain can

provide electrical impulses that are instructions, but it requires the

muscles to perform mechanical force. The muscle represents both the

H-bridge and the motor combined. The H-bridge takes in the small

electrical signal and translates it into high power output for the

mechanical motor.

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II. Project Requirment

1. MOSFET IRF 9540/540 2. MICRO-CONTROLLER (PIC16F67X)3. COMPARATOR LM3394. PMDC MOTOR5. DIODE 1N40076. PCB, WIRES, RESISTANCE, POTTENTIAL METER, REQULATOR

7805, etc.

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III. Design Schematic

The integrated circuit allows N-Channel Power MOSFETS driving in a full H-bridge configuration and is best suited for DC Motor Control Applications. The four drivers outputs are designed to allow MOSFET switching.

The speed and direction of the motor are to be set by two pins. Voltage across the motor is controlled by low side Pulse Width Modulation (PWM). This PWM feature can be made internally when the input pin is connected to an analog signal, or it can be given directly from a digital source.

Fig. Design schematic of H-BRIDGE QUAD MOSFET DRIVER FOR DC MOTOR CONTROL

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Fig. Microcontroller (PIC16F676) pin diagram

Moreover, integrates a 5V voltage regulator suitable as a power supply output for the microcontroller.Using this circuit speed control of DC motor is achieved.

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III.WORKING

Bridge : The power electronics actually form a letter H configuration, as shown in figure. The switches are symbolic of the electronic Power MOSFETs which are used for switching.

If it is desired to turn the motor on in the forward direction, switches 1 and 4 must be closed to power the motor. Figure below is the H-Bridge driving the motor in the forward direction.

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If it is desired to turn the motor on in the reverse direction, switches 2 and 3 must be closed to power the motor. Figure below is the H-Bridge driving the motor in the reverse direction.

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IV.Test Results

Fig. PWM Voltage Waveform on CRO

The advantages possessed by PWM techniques are as under:

(a) The output voltage control with this method can be obtained without any additional components.

(b) With the method, lower order harmonics can be eliminated or minimized along with its output voltage control. As higher order harmonics can be filtered easily, the filtering requirements are minimized.

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V.Picture of Final PCB

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VI. Picture of Simulation

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VII. Rating of MOSFET

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VII. Programing Microcontroller

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V. Applications and conclusion

Most often H-bridges are used to control rotational direction of DC motor. And unless you buy a potentially expensive motor-driver, you need an H-bridge to control any robot with a motor.

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