Claims:The scope of the invention is defined by the following claims:

Claims:
1. A method to control the speed of brushless dc motor comprising the following steps:
a) A transformer step down the voltage from the given input supply to required voltage. Bridge rectifier and blocking diodes coverts ac to dc voltage.
b) A small micro controller is organized in embedded c with the use of micro controller package and it’s interconnected with the data input device, OPTO isolator, LCD digital display and speed sensors.
c) A BLDC motor is connected with the help of a data input device.
2. As per claim 1, control system management is based upon PWM technique and a voltage regulator is used to regulate the voltage at desired level.
3. According to claim 1, PWM technique works by driving the motor with the series of ON-OFF pulses and varying the duty cycle. , Description:Field of Invention
The present invention relates to control the brushless DC motor at the required speed. Differing types of speed drives at out there within the market that are victimization varied management techniques, but here this method is meant with the assistance of closed-loop system management technique.
The objectives of this invention
The objective of this invention is to run the motor at twenty fifth, five hundredth or seventy fifth of the full speed after we set this share of speed from digital data input device, we use within the digital data input device to start out the motor.
Background of the Invention
A brushless motor has a rotor composed of a permanent field magnet, an armature functioning as stator and a position detecting element for detecting the positions of magnetic poles of said permanent magnet rotor and accordingly switching the electric current to an armature coil body of said stator thereby causing rotary motion of said permanent magnet rotor. Said armature coil body contains plural coils of given number of turns in a polygonal form of which at least two sides are placed parallel to the rotary axis of motor. Said coils are mutually arranged in a partially overlapping relationship to form a cylindrical body with one of said two sides being located at the internal surface of said cylindrical body while the other side is located at the external surface thereof so as to compose a coreless cylindrical armature body
Almost each mechanical action that we have a tendency to see these days is adapted by an electrical motor. Associate electrical motor takes the current as associate input and converts it into energy. The operation of AC Motor is same because the DC motor i.e. to convert current to energy. The fundamental distinction between these 2 motors is that the power provides that is associate AC supply input for AC motors and a DC supply input sort of a battery for DC motors. For each the motors i.e. AC and DC electrical motors carries with it a stator coil that could be a stationary half and a rotor that could be a rotating half or coil of the motor.
The regulation of an electrical motor is predicated on the interaction of flux made by the stator coil and therefore the current flowing within the rotor so as to supply move speed and torsion. In different styles of ratings and sizes. Number of the applications of huge electrical motors includes elevators, rolling mills and electrical trains. Few applications of tiny electrical motors are robots, cars and power tools.
In the recent past, variable speed driving systems have use in various small scale and large scale applications like automobile industries, domestic appliances etc. The usage of green and eco friendly electronics are greatly developed to save the energy consumption of various devices. This lead to the development in Brushless DC motor (BLDCM). The usage of BLDCM enhances various performance factors ranging from higher efficiency, higher torque in low-speed range, high power density ,low maintenance and less noise than other motors. The BLDCM can act as an alternative for traditional motors like induction and switched reluctance motors. (International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181). A brushless motor includes a rotor having a multi polar magnet with n-number of magnetic poles and a stator yoke having a plurality of field coils disposed at a position opposing the multi polar magnet. The stator yoke of the brushless motor is provided with a magnetic-resistance varying portion to improve the smoothness of rotation of the rotor. (US4902924A)
A brushless motor has a rotor composed of a permanent field magnet, an armature functioning as stator and a position detecting element for detecting the positions of magnetic poles of said permanent magnet rotor and accordingly switching the electric current to an armature coil body of said stator thereby causing rotary motion of said permanent magnet rotor. Said armature coil body contains plural coils of given number of turns in a polygonal form of which at least two sides are placed parallel to the rotary axis of motor. Said coils are mutually arranged in a partially overlapping relationship to form a cylindrical body with one of said two sides being located at the internal surface of said cylindrical body while the other side is located at the external surface thereof so as to compose a coreless cylindrical armature body.(US4130769A)
Accordingly, there is a requirement for a speed control of brush less direct current motor. The present invention overcome these problems observed in the prior art
Summary of the Invention
The primary objective of the present invention to provide a Closed Loop Control of a Brushless Dc Motor to run at the Required Speed.
The ultimate aim is to run the brushless DC motor at required speed by using closed loop control system. So that we can achieve the speeds at different levels.
The key feature of Closed Loop Control of a Brushless Dc Motor to run at the Required Speed is PWM technique. This technique works by driving the motor with the series of ON-OFF pulses and varying the duty cycle.
Brief Description of Drawings
The present invention will become better understood with regard to the following description and accompanying figures where in:
Figure 1 Block diagram of closed loop control of a brushless dc motor
Figure 2 Hardware module
Figure 3 Motor speeds at different levels
Detailed description of the invention
Electrical machines which have permanent magnet have many edges & benefits over magnetism machines which have the state of being excited and this excitation which has zero losses are finish in more potency, easy establishment, value might be a smaller quantity, maintenance value might be a smaller quantity and more torsion or more output power for unit volume. Excitation system of magnets was utilized for initial period in electrical machines among the primary nineteenth century. The presentation of this machine was terribly very bad due to bad quality of onerous material of magnetic type and hence used less. Once the creation of metal reinvigorated the usage of this system is inflated. Lanthanum magnets improve the pliability solidity and powerful performances of the machines. AC electric motors are most well liked machines as a result of to its construction is straightforward, value might be a smaller quantity, affordable dependability and low maintenance value among the 20th century .because of tiny air gap, lower potency and less power issue than alternator create synchronous machine prevailing in industrial purposes. Because of no brushes and commutator less there's no any downside of the moving parts.
Additionally as more chilling feature and it's the potential to manage at high speeds create them higher level quality dc machine. it has a disadvantage compared to its brushed equivalent in terms illustration and system style due to its paired nonlinear dynamics and multi-input nature. Due to the straightforward management technique, PMBLDCM are principally utilized in superior implementation. The main concern is the assembly of harmonic-less torsion. There are mainly 3 sources of torsion production in BLDC motors cogging torsion, reluctance torsion, and mutual torsion. Reluctance torsion is due to the variations in section L(mh), with reference to place. Reciprocal torsion is formed by the coupling between the field winding of rotor current and field winding of stator current. Hence, if the results of the section back voltage and section current are alike, torsion ripple is reduced and additionally the reciprocal torsion element is inflated. Finally closed-loop system speed management is finished by victimization PMW technique.
The brushless dc motor is actually a permanent magnet ac motor whose torque "current characteristics mimic the dc motor. Instead of commutating the armature current using brushes, electronic commutation is used. This eliminates the problems associated with the brush and the commutator arrangement, for example, sparking and wearing out of the commutator" brush arrangement, thereby, making a BLDC more rugged as compared to a dc motor. The control system management of our invention is designed with the help of PWM technique. This technique works by driving the motor with the series of ON-OFF pulses and varying the duty cycle. Once now changes then the output voltages square measure changes and by dynamic resulting voltages BLDC motor speed changes.
This methodology is directly as well as 230V ac, as a result of this methodology has electronic parts so these voltages square measure stand down into 9Vor 6V ac with the help of the stand-down ac electrical device..By using bridge rectifier this voltages are converted into DC voltages. With the help of voltage regulator these voltages are regulated into 5v DC. With the help of the regulated voltages Associate in Nursing OPTO isolator and a PIC microcontroller is powered up. The foremost management of the system is that the pic Microcontroller expeditiously and exactly has the tendency to control the motor speed. The small controller is organized in embedded c with the use of micro controller package and it’s interconnected with the data input device, OPTO isolator, LCD digital display and speed sensors. If the person wishes to drive the BLDCM at the required speed, the user simply clicks the speed with the help of a data input device.
As an Associate in nursing example, if person desires to drive the BLDCM at 25% speed then person can simply click the data input device buttons two and five. Similarly, the desired speed is entered and controlled by the user. The required speed is detected by the speed sensors and it offers the signal to the MC then it shows the speed at an alphanumeric LCD. So, that the required speed is well famous by the user. BLDC motor drives, systems in which a permanent magnet excited synchronous motor is fed with a variable frequency inverter controlled by a shaft position sensor. There appears a lack of commercial simulation packages for the design of controller for such BLDC motor drives. One main reason has been that the high software development cost incurred is not justified for their typical low cost.
Fractional/integral kW application areas such as NC machine tools and robot drives, even it could imply the possibility of demagnetizing the rotor magnets during commissioning or tuning stages. Nevertheless, recursive prototyping of both the motor and inverter may be involved in novel drive configurations for advance and specialized applications, resulting in high developmental cost of the drive system. Improved magnet material with high (B.H), product also helps push the BLDC motors market to tens of kW application areas where commissioning errors become prohibitively costly. Modeling is therefore essential and may offer potential cost savings. A brushless dc motor is a dc motor turned inside out, so that the field is on the rotor and the armature is on the stator
3 Claims & 3 Figures