How to control the DC-Motor by using H-Bridge techniques?

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A
Seminar Report
On
Controlling DC Motors with
H-
idge Driver

Submitted in partial fulfillment of
the requirements for the degree of
Bachelor of Engineering
In
Electrical (Electronics & Power )

of
Submitted by
Under the esteemed guidance of
Contents
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Acknowledgement
CONTENT
Abstract
1. Introduction
1.1 H-
idge Basics
1.2 H-
idge Driver Topology
2. The Ideal H-
idge Drive
3. PWM Speed Control Techniques Using ROHM H-
idge Drivers
3.1 MCU Control
3.2 Analog Voltage Control
3.3 Fixed Speed From an Unregulated Supply
3.4 Simplified Digital Speed Control
3.5 Soft-Start Control with Analog Input
4. Popular Application
5. Selecting the Right H-
idge Driver for the Application
6. Conclusion
7. References and External links
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ABSTRACT:
Due to efficient control methods, DC motors are widely used motors to drive the loads in
industry. Among the different control techniques for the DC motor speed control, armature
voltage control method using Pulse Width Modulation (PWM) technique is the best one. We can
ealize the PWM control method using a chopper, build with semiconductor switches, such as
BJT, MOSFET, IGBT’s and also using an H-
idge built with MOSFET, IGBT switches, we
study the H-
idge with MOSFETs and control the input voltage of the DC motor using PWM
technique. To generate PWM control signals, we use AT89C51 microcontroller, one of the
popular 8051 microcontroller family members. According to the user’s required speed,
AT89C51 based control circuit generates appropriate PWM pulses. .
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Controlling DC Motors with H-
idge Drive
Introduction:

DC motors are increasingly required for a
oad range of applications including robotics,
portable electronics, sporting equipment, appliances, medical devices, automotive applications,
power tools and many others. The motor itself is a prefe
ed alternative because it is simple,
eliable and low cost. Equally important, advanced, fully-integrated “H-
idge” driver ICs are
available to control the motor’s direction, speed and
aking. This report will explore the basics
of H-
idge drivers and discuss the advancement of the technology from discrete solutions to
highly-integrated ICs. It will compare linear motor speed control with more advanced, higher-
efficiency pulse-width modulation (PWM) techniques.
Integrated timing and control circuitry as well as the unique capability of handling either
analog or digital (PWM) speed control inputs. The report will also describe the benefits of these
advanced motor driver ICs particularly in terms of their exceptional efficiency, integrated fault
protection, small package size, symmetrical pin configurations and pin-compatibility with earlier
(linear output) models. Finally, a summary of the range of H-
idge ICs offered devices specified
with 7 V, 18 V and 36 V VCC.
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H-
idge Basics:
The H-
idge circuit derives its name from the full-
idge circuit shown in Figure 1. The
motor forms the cross-piece in the “H.” Speed and direction are controlled as cu
ent flows
through the motor in the direction determined by the position of the switches in the
idge. In
this example, with switches “A” and “D” closed, the motor will operate in a clockwise (CW)
direction. With “B” and “C” closed, the motor will operate in the counter clockwise (CCW)
direction.


In the linear output control implementation, the motor speed control is determined by the
voltage applied across the motor. In the PWM implementation, the speed is controlled by the
width of series of pulses of equal voltage. In either case, motor direction is controlled via
separate logic inputs.
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While the concept is simple. Controlling the operation of the switches and preventing
simultaneous closure of the CW and CCW control outputs, particularly when reversing the
direction of the motor or changing speed by H-
idge controller. The H-
idge controller is then
connected to four devices forming the legs of the
idge. In a discrete solution the designer must
deal with voltage control levels, timing to prevent shoot-through and the proper selection of the
semiconductor switches. The discrete solution also requires additional circuitry for functions
including overvoltage, overcu
ent, overtemperature and electrostatic discharge (ESD)
protection. All of this translates to a fairly complex design.
H-
idge Driver Topology:
Integrated H-
idge drivers are constructed by combining a...