View source for H-Bridge and other Motor Drivers

{{Template:Infobox_Generic
| Name                                        = LN298 Dual H-Bridge
| Image                                       = H-Bridge LN298.jpg
| SensorType                                  = 
| ProcessorType                               = Chip L298N (ST NEW)
| Frequency                                   = 
| Language                                    = 
| OS                                          = 
| IOPins                                      =
| TypicalVoltage                              = 5.0 V
| TypicalCurrent                              = 0 mA - 36 mA
| MaxVoltage                                  = 35 V
| MaxCurrent                                  = 2 A (MAX single bridge)
| Protocols                                   = Compatible with L297/L298 driver
| Range                                       =
| Cost                                        = $3.99
| Website                                     = [http://courses.jamesmpoe.com Course Website]
| Student                                     = [mailto:christian.hage001@mymdc.net Christian Emilio El Hage]
}}


An H bridge is an electronic circuit that enables a voltage to be applied across a load in either direction. These circuits are often used in robotics and other applications to allow DC motors to run forwards or backwards.

Most DC-to-AC converters (power inverters), most AC/AC converters, the DC-to-DC push–pull converter, most motor controllers, and many other kinds of power electronics use H bridges. In particular, a bipolar stepper motor is almost invariably driven by a motor controller containing two H bridges. <ref>[https://en.wikipedia.org/wiki/H_bridge H-Bridge Wiki Page]</ref>

== History of Motor Drivers ==

*I could not find much history on H-bridges, so I found this paper on the History of Power Electronics for Motor Drives in Japan
 
Power electronics today is one of a wide range of well defined technologies. It has a key role in the transformation and adaptation of electrical energy between the supplier and the user. As the motor drive is one of major application fields of power electronics, a lot of developments have been achieved and evolutional systems have been produced for motor drives in Japan. The emergence of many kinds of power semiconductors and the digital control technology such as the use of microprocessor, made it possible to realize epoch-making products. In this paper, the 50-year history of power electronics for drive systems in Japan is summarized. In the first place the developments of power semiconductor devices and cooling systems are stated. Afterwards various converters and their control methods are sorted out and classified with historical events. Finally the developments in three application fields, which are the industrial field, the railway, and the elevator, are presented with the introduction of major products. 

The invention of the transistor in 1948 revolutionized the electronics industry. Semiconductor devices were first used in low power level applications for communications, information processing, and computers. In 1958, General Electric developed the first Tyristor, which was at that time called SCR [1]. With the arrival of Thyristors, the era of power electronics began. The progress of power semiconductor devices is summarized in Fig. 1. Since the production of the 400 V 80 A Thyristor with the wafer of 20 mm’s in diameter in 1961 in Japan, development work led to a constant improvement in the semiconductor components and the assorted circuit technology, resulting in rapid development and the extension of the classical converter technology in Japan as well as in the USA and Western Europe. Since then, a steady growth in the ratings of the Thyristors and their operating frequency has enabled extension of their application to motor control. The increase in current ratings of the Thyristors has been possible by the availability of larger-diameter silicon wafers. Single devices are now manufactured with wafers of 6 inches in diameter. The high voltage blocking capability of the Thyristors has been achieved by the ability to produce very uniformly doped high-resistivity N-type silicon by Neutron Transmutation Doping (NTD) since the 70s. As the NTD process allows the conversion of a silicon isotope into phosphorus by the absorption of a thermal neutron, a very uniform doping can be produced throughout the wafer. Especially the large investment in the Japanese steel industry in the 70s gave impetus to the development of the Thyristors of higher ratings. The 2500 V Thyristor and the 4000 V Thyristor were respectively developed for the 750 V DC motor in 1967 and the 1200 V DC motor in 1976. The 8000 V 3500 A light-triggered Thyristors with 6 inch wafers were used for the DC power transmission system in Kii channel of Japan in 2000.
Since around 1975, more turn-off power semiconductor elements were developed and implemented during the next 20 years, which have vastly improved modern electronics. Included here are improved bipolar transistors (with fine structure, also with shorter switching times), Field Effects Transistors (MOSFETs), Gate Turnoff Thyristors (GTOs) and Insulated Gate Bipolar Transistors (IGBTs). 

[[File:Figure 1.png]]

You can read more on the history of Motor Driver from this paper through this link [http://www.ieeeghn.org/wiki/images/4/49/Yano2.pdf HERE] <ref>[http://www.ieeeghn.org/wiki/images/4/49/Yano2.pdf History of Power Electronics for Motor Drives in Japan]</ref>

== Purpose of the H-Bridge ==

The H-Bridge is designed to drive a motor clockwise and anticlockwise. 
To reverse a motor, the supply must be reversed and this is what the H-Bridge does. 
An H-Bridge can be made with SWITCHES, RELAYS, TRANSISTORS or MOSFETS. 
Note: Some circuits are just demonstration circuits and need "damper diodes" (protection diodes) to reduce spikes.  

Three Things 
To drive a motor forward and reverse, the circuit must deliver a voltage in one direction, then in the opposite direction. 

It must also be able to deliver a "running current" (operating current) (say up to 1 amp) and a "starting current" (up to 5 amps), and a "loaded current" (up to 5 amps). The transistors must be capable of passing a "stalled current" without being destroyed. 

The power supply must be capable of delivering a high current so the motor will START-UP under load. <ref>[http://www.talkingelectronics.com/projects/H-Bridge/H-Bridge-1.html The H-Bridge]</ref>

== Physical Implementation and Design ==

In general an H-bridge is a rather simple circuit, containing four switching element, with the load at the center, in an H-like configuration:

[[File:Image 1.png]]

The switching elements (Q1..Q4) are usually bi-polar or FET transistors, in some high-voltage applications IGBTs. Integrated solutions also exist but whether the switching elements are integrated with their control circuits or not is not relevant for the most part for this discussion. The diodes (D1..D4) are called catch diodes and are usually of a Schottky type.

The top-end of the bridge is connected to a power supply (battery for example) and the bottom-end is grounded.

In general all four switching elements can be turned on and off independently, though there are some obvious restrictions.

Though the load can in theory be anything you want, by far the most pervasive application if H-bridges is with a brushed DC or bipolar stepper motor (steppers need two H-bridges per motor) load. In the following I will concentrate on applications as a brushed DC motor driver.

 Static Operation

The basic operating mode of an H-bridge is fairly simple: if Q1 and Q4 are turned on, the left lead of the motor will be connected to the power supply, while the right lead is connected to ground. Current starts flowing through the motor which energizes the motor in (let’s say) the forward direction and the motor shaft starts spinning.

[[File:Image 2.png]]

In a bridge, you should never ever close both Q1 and Q2 (or Q3 and Q4) at the same time. If you did that, you just have created a really low-resistance path between power and GND, effectively short-circuiting your power supply. This condition is called ‘shoot-through’ and is an almost guaranteed way to quickly destroy your bridge, or something else in your circuit.

[[File:Image 3.png]]

Because of this restriction from the four possible states the side-A switches could be in only three make sense:

[[File:Chart.png]]

<ref>[http://www.modularcircuits.com/blog/articles/h-bridge-secrets/h-bridges-the-basics/ Modular Circuits]</ref>

== Applications for the H-Bridges ==

Found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, power tools, and disk drives, electric motors can be powered by direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or by alternating current (AC) sources, such as from the power grid, inverters or generators

Small DC motors are used in tools, toys, and appliances. 

The universal motor can operate on direct current but is a lightweight motor used for portable power tools and appliances.
 
Larger DC motors are used in propulsion of electric vehicles, elevator and hoists, or in drives for steel rolling mills.
 
The advent of power electronics has made replacement of DC motors with AC motors possible in many applications.

Industrial type of AC motors are widely used for pumps, blowers, conveyors and other industrial machinery.

== Schematics to use the H-Bridge ==

[[File:Schematic Hbridge.png]]

[[File:Motordrive schematics.png]]

== Code to Control H-bridge ==

Thise is an exsample of a simple bash script to drive motor using wiring pi

motor 1 forward:

#!/bin/bash
gpio mode 0 out
gpio mode 1 out
gpio write 0 1
gpio write 1 0

motor 1 backward:

#!/bin/bash
gpio mode 0 out
gpio mode 1 out
gpio write 0 0
gpio write 1 1

motor  1 Stop:

#!/bin/bash
gpio mode 0 out
gpio mode 1 out
gpio write 0 0
gpio write 1 0

motor 2 forward:

#!/bin/bash
gpio mode 2 out
gpio mode 3 out
gpio write 2 1
gpio write 3 0

motor 2 backward:

#!/bin/bash
gpio mode 2 out
gpio mode 3 out
gpio write 2 0
gpio write 3 1

motor 2 Stop:

#!/bin/bash
gpio mode 2 out
gpio mode 3 out
gpio write 2 0
gpio write 3 0

== How H-Bridges Work (VIDEO) ==

https://www.youtube.com/watch?v=iYafyPZ15g8

== Different Version of the Device ==

[[File:Hbridge ic.jpg]]

[[File:Hbridge2.jpg]]

[[File:Hbridge.jpg]]

== Where to Purchase H-Bridges ==

Device name	         Website	        Price	      Link to product page

Dual H-Bridge Motor Driver for DC or Steppers - 600mA - L293D	Adafruit	$2.95	[https://www.google.com/aclk?sa=l&ai=DChcSEwjHmYGIqerRAhXYA4EKHQX6Ch4YABAB&sig=AOD64_0mUods0umln2cb027NBzNfQB3fCA&ctype=5&q=&ved=0ahUKEwj-mv2HqerRAhXHNiYKHU9_C8MQ2CkI3gUwAA&adurl= Adfruit]

L298N Dual H Bridge DC Stepper Motor Controller Module for Arduino    $6.94	[https://www.google.com/shopping/product/4697569923230100682?q=H-bridge&rlz=1C1CHFX_enUS583US583&espv=2&biw=1680&bih=895&bav=on.2,or.r_cp.&bvm=bv.145822982,d.eWE&ion=1&tch=1&ech=1&psi=XVCPWMCTF8XrmQGdjaK4DA.1485787229981.5&prds=paur:ClkAsKraXzPglzAfPDJ4W_OVnUOgYYEvUZw0dT0js9o6ExNEhbSWg_RipGX-9K9iUvD8sFWi2Z8Q2XVPbUMRX6B6FQaoiykznitrFnA4rxfgN5Vce5W4-Jk9-BIZAFPVH73sidiWDlU3kZ_5pbAALqUAAXVRag&sa=X&ved=0ahUKEwj-mv2HqerRAhXHNiYKHU9_C8MQ8wII5gUwAQ SeeedStudio]

Devantech MD03 24V 20A H-Bridge DC Motor Driver
	        Robotshop.com	$106.75	[http://www.robotshop.com/en/devantech-md03-50v-20a-h-bridge-driver.html?gclid=Cj0KEQiA5bvEBRCM6vypnc7QgMkBEiQAUZftQCp6ZJGwKNiGELNAq9dgncScBmmClx5ldtwkZ_Exq9saAoci8P8HAQ Robotshop]

== References ==
{{Reflist}}