Control The Speed Of The DC Motor Engineering Essay

Control The deal on Of The DC get Engineering EssayDirect original (DC) move is applied in a wide range of maskings tidings classicularly in automation technology due to minimal electromotive force consumption. In the proffer DC aim plays an effective role in Hardw atomic number 18 implementation. The primary(prenominal) principle behind the project is to use the exhi playi bingler say-so to break loose the DC force back its mavin of stovepipe feed ass take forlers. For estimating the velocity and the armature accepted of the DC motor with 24 volts and a ds moving picture Micro curbler is classmed .The preceding(prenominal) completely operation is finished with(p) in a unlikeable have eyehole function.Table of confine1.2 Objective2. Specific objects of the projectChapter 11. Introduction1.1 Background brushed DC locomoteDC motor modelDigital watch of dc motorAdvantages of dc with respect to despatch fancy par bothel of latitude control of dc motor2. 1 ds PICdsPIC30f 30102.2 MPLAB IDE3. Design and look intoCascade control flowing closed racing locomote dynamicsSpeed kink dynamics3.1 Components for absolute 24v brushed Dc motor3.1. Flexible change come along3.2.1 Gene rank PWM curve earns3.1.2 H-Bridge converter3.2 Softw ar techniques employ in DC motor class micro control condition in Flexible inverted mount4. Results and Discussion5. Conclusion6. appendixList of Figures get wind 1 Operation of BRUSHED DC re thrill trope2 General elude draw of velocity circulate and up-to-date entwine of DC rideFIGURE3 H-bridge converter with diametric potentiality V VCHAPTER 11. INTRODUCTION1.1 ObjectiveThe important function of the project is to control the hurrying of the DC Motor using a dsPIC30f3010 microcontrol. For that implement a separate computer hard liquidate to satisfy the main function of the project.1.2 Specific Aim of the projectIn roll to achieve the main core of the project, set out Hardwargon for despotic the f number control of DC motor. The main ironw atomic number 18 extremitys beds PIC microcontrollerICD embrasure wine connector for outline larboardDC function supplyMOSFETCurrent sensing elementsThe above components are involve to construct a hardware nameed Flexible Inverted Board 4.1.3 lineation OF PROJECTStep1In this paper a flexible inverted board is constructed with the series of hardware componentsStep2 because communicate the Flexible inverted board with system using MPLAB IDE software system with ICD-3 interface 4.the language employ in the MPLAB software is C-language.Step3The locomote draw in and the certain loop are the twain key functions for controlling the f number of the Dc motor. In our project the hear forefront is to control both the loops by C-programming language using MPLAB ICD-3.The hurrying loop of the microcontroller is called drive on controller and the reliable loop of the microcontroller is called afoot(predicate) co ntroller.CHAPTER 2THEORITICAL TECHNIQUES AND THEIR REVIEWS2 Background2.1 Brushed DC MotorIn self-propelled industries DC motor is used widely in fuel marrow control, electronic steering control, engine control and electric vehicle control 6for its cost effective and it is used in m whatsoever applications like bod and paper industries, fan pumps, press, winder motors 2,home appliances, washers, dryers and compressors6 are some of the best archetypes. DC motor is one of the im wayant hardware employed in this paper, it consists of a rotor coil coil and stator, and the parts are placed in a immutable magnetic field. Commutator and brush are placed in in the midst of the rotor and stator. Positioning the brush at a particular direction in the rotor is classified into some categories and they are radial, trailling or leading 3 positions. When the rotor rotates the commutator and carbon brush interface at a point, which produces an enormous cadence of magnetic field from the bru sh of the motor and it produces current to the armature flatus of the Dc motor.FIGURE 1 Operation of BRUSHED DC Motora2.2 DC Motor model 8Each motor provide have different precondition and requirements. According to motor requirements and inside information the model keep be designed. The propose of motor model, deals with controlling the applied potency of both cannonball along and current. The staple fiber model for a Dc Motor is shown underFIGURE2 DC Motor modelThe above plot is a simple RL go. RL circuit is called shield inductance circuitand a 24v DC Motor. All these components combine to form RL circuit.Now the derivation part of the RL circuit is explained beneathT (t) = Jw is the Angular velocityJ is the moment of inertiaB is the frictionT is the armature TorqueT (t) = (t)is the Torque constantis Armature currentAccording to Kirchhoffs law(t) (t) = (t) +and are the inductance and resistance for the armature current (ia)The electromotive of the motor earth-clos et be de borderined by multiplying the back emf with speedThe relationship for the electromotive force is shown beneath(t) =The affirm model for whatever DC motor using ia and w (speed) is mentioned below.= +2.3 ds PIC -microchipds PIC stands for Programmable Interface Controller or programmable intelligent computer, which act as an measurable controlling unit for entire system. The main objective of this project is to take in the ds PIC to generate 6PWM waveform. In an ideal condition the waveform from the pulse largeness inflexion arse control the H-bridge converter. It not unless serves as an interface controllers however to a fault plays a role of a programmable logic controller (PLC). 16,20ds pic has a storage of 16bit microcontroller that has both major functions. Firstly it offer act as a software part serving software functions and the other is a hardware part serving hardware functions.The infix tokens that are attain from the feedback serve system are rece ived by the software part which in sophisticate utilizes the codes that are written on the chip on C language to analyze the input and operate the hardware. Finally the software makes sure the hardware runs found on the software functions to understand the needed produce. 18, 20Our project arduous on working experiments that were run at lab conditions. Since a couple on of systems have certain differences from the stimulation that have been run in accredited conditions compared to ideal conditions. This in turn is the working of the microcontroller.dsPIC30F 3010, 2010 4011 and 3012 are the series of chips that have been gettable in the Lab. The letter F in ds PIC30F and such(prenominal) chip states that the chip contains flash retrospection. The reason for considering this flash retrospection intersection point is because 30F has an ex-ordinary instruction execution when compared to EPROM (Erasable Programmable Read-Only Memory) and one fourth dimension programmable c hips (OTP). This has been a major requirement for the running of this project to get the required payoff.16-bit modified Harvard architecture has been added to the processor containing ds PIC30F for utilizing the info and upgrading the set of guide lines for running digital omen processing (DSP) 14. on that point is a lengthy flexible opcode field which has been installed in the CPU that has a 24 bit wide user software engineer retrospect area and the total embraceing speed terminate go up to 4M-24 bit. This programming model has sestetteen 16bit working registers in ds PIC30F chip. in that location are devil classes of introduction controlling unit that have been coordinated and used for execution they are integrated and used for execution 2.2.3.1 dsPIC30F 3010This section is about the joystick configuration and the components available in dsPIC30F3010 microcontroller. Normally the memory allocation in dsPIC30F 3010 displace classified in to three categories they are S thrust in BytesEEPROM in BytesProgrammable memory in Bytes/instruction2.3.1.1 S wadSRAM stands for dormant RAM (Random Access Memory). According to the tabulation shown below the data saltation for static RAM should not exceed 1024 bytes. The memory in the function tail assembly classified in two types they areX Data RAMY Data RAMThe static RAM uses X -RAM and Y_RAM for storing datas.2.3.1.2EEPROMThe memory allocation for EEPROM is aforementioned(prenominal) as static RAM. In read exactly memory one of the im lookant types of ROM used to store memory is EEPROM. The main function of this ROM is based on two parameters they are endurance and retention 2. Endurance is to retain the data even afterwards the ROM fails. Therefore the data cant be deleted at any instant. sentence current is required to store data that is taken charge by retention 2.2.3.1.3Program memoryIn a particular program ds PIC30f microcontroller has a separate memory allocation for storing both the addre ss and data. The memory restrict for the program memory is 24K.program address infinite anda data address spaceTABLE 1 Tabulation for memory allocation in ds PIC30f3010The pin configuration of dsPIC30f3010 is described belowFIGURE 3 Pin configuration of dsPIC30F 30102Pin descriptions(PWM1L and PWM1H), (PWM2L and PWM2H) (PWM3L and PWM3H) 2 these are six different types PWM channels used in the pin configuration. In which from distributively one PWM pair generates three duty beats with one high output (H) and one low output (L).INT0, INT1INT2 are the amputate buffers used in the PIC. VSS and VDD 2 are the supply potentiality and ground in the PIC controller.U1RX U1TX, U1ARX U1ATX 2 are the series of pins used for communicating PIC microcontroller with PC, in other system interface operation can be done by UART function. In that RX stands for manslayer and TX stands for transmitter. The above pin function plays an important in our project.CHAPTER 3 methodology3.1 Components for controlling 24v brushed Dc motorSince the project is fully based on hard ware so some(prenominal) components are available and how they work in that operation.3.1.1Cascade control operation in Dc MotorThe below operation is done by using Double rain shower downd layout, it consists of two loops they are current controller with current reference and speed controller with speed reference 5 as shown in .FIGURE4 General block plat of speed loop and current loop of DC Motor bThe current loop is c everyplaceed by the speed loop, in the block draw it has the two mobilises inner circle is called inner loop and the outer circle is called outer loop since the inner circle operation is unendingly faster than the outer circle. In other words inner circle performance is multiple of ten clips quicker than the remaining one. The cascade control principle is mainly used in our project to maintain the speed of the motor at a constant direct and the current loop in the cascade control is the armature current and it is otherwise called as torque. sometimes armature current may exceed the terminus ad quem to avoid this situation in cascade control, it has clipper ship, and the main function of the limiter is to limit the values of the armature current. For eccentric To limit the armature current to 64volt i.e. 1 ampere. So that the armature wont exceed those limits since the limiter is available in cascade control. The speed controller in the cascade control used to produce demand current ia*. The motor runs to dominate the demand current values. The demand current value leave behind always higher than the normal current values. So that the speed motor little by little increases.PI controller(proportional Integral controller)Current controllerSpeed controllerThe above all components construct a cascade controller and the function severally component is described below3.1.1.1PI controller (proportional and entire controller)In cascade controller function non-h omogeneous controllers are used for detecting the speed and control of the motor, but PI controller is recommended as high economical controller because it consist to constant view Kip and Kid. By manually tuning the gain of both Kii and Kpi will reduce the steady state demerit and the stableness of the system will be increased. In modern survey more than 70% cascade controller used PI controller for controlling the speed control DC Motor. In order to reduce the steady state fault in the closed loop system, gradually increase the proportional gain constant Kp. As the gain of the Kp increases the steady state error in the system decreases. But the stability of the system will not be stable. To make the system stable, integral term Ki is introduced in the system. When both the proportional and integral term sum each other to reduce the steady state error and make the system stable .the above two functions can be done simultaneously in the PI controller. The mathematical expressio n for PI controller is explained below.FIGURE 5 PI controller of a closed loop function 1Kp-proportional gainKi-Intergral gainY- Output of the PI controller slew-Error in the PI controllerAt the beginning error (Err) will pass through both Kp and Ki.For proportional gain the output is Kp Erry1= Kp Err eqn1 1y2 = eqn 2 1y = y1 + y2 eqn 3 1eqn 4 1The key point in this PI controller is the error Err in intergral gain Ki will be integrated. so that the steady error will be reduced and the system will be stable.3.1.1.2Current controllerThe current controller in the closed loop functions of the cascade control. The current loop is also called as current controller. It is used to protect cascade circuit from damage. The main function of the cascade function is to control the speed. Before controlling the speed the current of the controller should be controlled. The current obtained from the closed loop function is from armature circuit of the DC Motor 7.the input in the current controller is the back emf (ia*).Power converter is mainly used to improve the control in the system. It has high turn relative absolute frequency, since the personnel converter in the current loop is very quick. The output of the converter is armature electromotive force (Va).(-E) is the worry occurred in the current loop, in order avoid the disturbance-Eiaia*RL CIRCUITTPower ConverterPIFIGURE 6 Functional block diagram of Current controllerThe disturbance is added along with RL circuit, and the equation is shown belowVa = (S La + Ra) ia + EThe function of the RL circuit is reduce complexityVa is Armature electromotive force.ia is armature current (trying to control)Ra is Armature resistanceE is DisturbanceRL = 1/(S La + Ra)Current loop is carried out by transmitting the from ia(armature current) to ia*(demand armature current). As quick as possible without making the over shoot getting so high. If the over shoot is high it creates problem to the converter. Similarly when the gain valu es (Kp and Ki) increases in PI controller the over shoot value reduces, but the same time there is more amount of oscillation which may cloak the system. Care should be taken in choosing both Kp and Ki values.tsiaia**FIGURE 7 graph for armature current vs settling timeia Armature currentia* read armature currentts Settling time3.1.2 Flexible inverted boardThe major hardware has been designed and implemented as Flexible inverted board.It consists of many components they are dsPIC30F3010 microcontroller, H-bridge converter and dc motor. The functions of these hardware components are explained earlier. The above all operation is implemented in a single hard ware called flexible inverted board.FIGURE 8 Functional block diagram of Flexible inverted board3.1.2.1 IR2130 gate ingest circuitThere are three input signal generator blocks which are surefooted of providing two outputs each gives the inputs to the six output drivers. L1, L2 and L3 are signal generators which drive precisel y the three low-side output drivers although H1, H2 and H3 signal generators must(prenominal) be level shifted before it is fed to the high-side output drivers.The floating points of the driver, gate charge requirements of the power switch and the maximum power switch ON times receives power from three bootstrap capacitors C1, C2 and C3. Bootstrap capacitors also feed supply to the inhering floating driver current. Once these energy requirements are met there must be considerable amount of charge still on the 8.3V nominal to prevent stopping. D7, D8 and D9 should be super-fast.VCC level seen by an under- potential drop detector circuit gives an input to outlaw six outputs of the signal generator circuits. Current sensor R1 derives the ITRIP signal in the main power circuit of the motor when it is segregated with a 0.5 volt reference to outlaw the six signal generator outputs. ITRIP inputs sets up a fault logic circuit which in turn gives circularize drain TTL output for system ge sture.FIGURE 9 Circuit diagram for IR2130 gate drive circuit3.1.2.2Trim port function with PWMTrim port are miniature in size and they are very small in size .it is mainly used in many PCB look board since its occupies less space.The mow port act like a potentiometer and it is otherwise called as trimmer . By tuning the trim port, resistance value can be minimized or maximized. For example if a 50ohm resistance can be tuned by trim port from 0 50.The two leg of H-bridge converter produce two pulse wave form one with low output (1L) and another one with high output (1H). The duty ratio of the PWM wave form can adjust using trim port.3.1.2.3DC MOTOR ENCLOSED WITH A ENCODERThe best methods of calculating the speed of the DC motor is using optical encoder method. It consists of a disk, Light Emitting Diode (LED) and optical sensor 6. The disk is fitted with the rotor, as the rotor rotates the disk starts spinning along with the rotor and it is placed in between the LED source and t he light sensor. Once the rotation starts the disk passes through the LED source and the optical sensor gets started, from which the speed of the motor can be calculated because the optical sensor acts like a tachometer. In other words the encoder in the DC motor is otherwise called as speed detecting sensors. 63.1.2.4 H-Bridge converterDC motor runs differential speed, but the applied voltage of the motor varies at every interval of time. Since the voltage is directly proportional speed, as the voltage increases the speed of the motor also increases. Speed can be calculated by tachometer which is in build in the DC motors, the applied voltage can be supplied and controlled by a converter called h-bridge converter.GDGD Gate motility CircuitFIGURE 10 H-bridge converter with different voltage V VcIn this H-bridge circuit it produces two unipolar pulse comprehensiveness transitions because it has two leg inverter. Effective modulation takes place only if in the first half of the inverter. As a result two multivariate voltages are generated on either side of the armature winding.In H-bridge, modulation index is represented as (+mi) and the reciprocal of modulation index is represent as (-mi).the motor in our project actually experiencing two pulse width. two the pulses are inversely proportional to each other producing a unipolar PWM.The two legs in the converter are called the switching signals or switching frequency. Bigger converter relatively has lower frequency and smaller converter has higher frequency. If the frequency in the leg1 is high in contrast the frequency in the leg2 will be low.In our project consider V and V are the switching channels of the H- bridge converter . they are inversely proportional to each other.The pallbearer signal is called the input frequency . the carrier frequency used in our project is 10khz. According to the carrier frequency the time period of V and V differs.In C coding V and V is mentioned as PDC1and PDC2 from th e below graphFIGURE 11 graphical imitation of PWM signals in H- Bridge converter.The output voltage of the h-bridge converter can be obtained both negative and positive voltage distribution 1. Pulse width modulation in the h-bridge converter helps to control the armature circuit of the DC motor 1. Maximum armature current (torque) can be obtained by comparing time constant of both field winding and the armature winding 1. Since the motor is connected directly to the field windings supply voltage in the field winding is more when compared with the armature winding. To maintain equal time constant in both field and armature winding 1, the applied voltage in the armature winding should be increased, as the armature current increases the torque output is maximized 1.3.1.3 Generating PWM wave formsAs the torque output gets maximized, pulse width modulation is introduced in the H-bridge system to avoid the disturbance in the armature current.it can be done by increasing the frequency lev el of the H-bridge converter at a higher range.As the torque output gets maximized, pulse width modulation is introduced in the H-bridge system to avoid the disturbance in the armature current.it can be done by increasing the frequency level of the H-bridge converter at a higher range.FIGURE 12 Diagrammatic representation of the pulse width modulation is shown below 6The below specification is referred from 6 long ton Time is ON (applied voltage)Toff Time OFF (applied voltage)T Time period.Duty cycle =.The average voltage of the DC motor can be shown in an equation belowAverage = Duty cycle - Vin 6When the motor is running at a constant speed the back emf of the motor is also remain constant.As the back emf remain the same the motor running at constant speed and the armature current (Ia) is zero. PWM is one main part that is required for the operation of cascade control.4. Software used to drive the Motors4.1 scheduling microcontroller in Flexible inverted board using C-languageI n the flexible inverter board PIC microcontroller plays a major position in directing the pulse width modulation. The net ton time in the pulse width modulation (PWM) signal can be modulated or controlled by the microcontroller, as the microcontroller varies the time, the velocity of the motor changes with respect to time. The Programing language used in microcontroller is embedded C. The programming codes are downloaded in the microcontroller chip, the downloading approach can be done by a software development tool called MPLAB, this software exists in observe the systems, this software should be first installed in the PC, the programmers will write the codes to modulate the PI controller to acquire Applicable source from the current loop of the cascade control function. Once the codes are accepted according to the current loop 1, the programs can be downloaded in the microcontroller through universal successive bus or in circuit Debugger (ICD) ICD is a bus which interfaces PC system and the flexible inverter Board. 6In order to program the microcontroller examine whether the hardware components are interfaced with the controller. The programming language used for programming the controller is C language. In c-language the datas are classified in to input data and output data. The microcontroller send the development in parallel of latitude signal, where the C-language wont accept latitude signals .To avoid the situation ADC converter and encoder interface are introduced in the system. ADC stands for analogue to digital converter it converts the analogue signal in to digital signals. Then the digital signals get received by the C-program as input data. In turns c-program will send the output data to the PWM unit. UART communication system is a bidirectional so that microcontroller and PC can communicate simultaneously. UART stands for universal asynchronous receiver transmitter. The basic diagrammatic representation for system communication with C-lang uage is shown belowFIGURE 13 System communication in C Programming Language.In C-language firstly initialise all the functions required for the speed control of motor.4.1.1Current sensor inputThe current in the motor coils is one important parameter in the effective running of the motor. So it is essential to sum of money the value of this current. The measurement of the current is performed by using special sensors call Hall Effect Sensors. The range of the current is determined by the rating of the motor. Any over current in the motor can severely damage the motor. The Hall Effect sensors produce a voltage synonymous to the phase current. This is fed to the ADC inputs of the micro controller where it is converted into the digital signals. This is wherefore fed into the microcontroller program. Hence the current needs to be limited inside specific limits.CL1, CL2 and CL3 are the three current sensors variables used in this coding. The bit ratio of the ADC input is 10 so the in put data ranges from 0 to 1023. The maximum data limit for the current sensor is 1023.so the current sensor value in the C- code is initiated asCL1 = 511 CL2 = 511 CL3 = 04.1.2 Encoder inputFor any speed controller, the actual speed of the rotor forms the basis for the control signals. The speed control signal can be changed only if there is an error between the actual speed of the rotor and the desired speed of the rotor. If the metric speed is less than the desired speed then the PWM pulses are alter accordingly to increase the speed. To perform this action a barb encoder is used. The shaft encoder uses an opto-mechanical system to generate pulses.These pulses then are used to derive the speed of the rotor. A reference pulse is used as an indicator to bet the pulse. This information is fed to the microcontroller, which then uses a special timing circuit that processes these encoder pulses. The motor speed to be accessed by the microcontroller needs to be stored in a variable w ithin the micro controller code. The variable used in this program is a variable called rpm. This variable is accessed to calculate all functions related to the motor speed.4.1.3 Pulse Width ModulationThe MOSFETs in the circuit is used as switches. These MOSFETs are switched according to a PWM. To drive these MOSFETs a gate driver circuit is required. The gate drive signal generates the voltage required for the operation of these MOSFETs. The PWM is generated by the microcontroller according to the program and is supplied to the gate drive circuit. The PWM signals are separate for each if the 3 legs of the MOSFET inverter. Each of the PWM requires a modulation index to generate the signal. These modulation indexes are stored in a register. The registers are named as PDC1, PDC2, and PDC3. These variables are very crucial in generating the PWM signals for the MOSFET drivers. Since data limit is 1023.4.1.4 initializing the code in C languageBefore performing any function in C-language , it requires an initialisation. It is important to initializing the variable of a function. Some the functions are initialized below.Init PORT ()This function initialize the digital input and output port or analogue input and analogue output of the microcontroller.Init UART ()It is one of pin in the microcontroller .The main function of the UART is used for bidirectional communication with PC. Since UART can able to detect the transmission speed in data rapture between the microcontroller and PC. The maximum transmission speed is around 19200.the data canalize wont exceed the limit.Init PWM ( )The input frequency of our PWM signal is 10kHz.the time limit for the modulation index is around 0-1474.in the h-bridge converter has two legs so each leg produces a PWM signal with a maximum time limit of 0-737. Hence the Ton time of PWM signal will be in 11 duty ratio.Init ADC ( )It is used to convert the analogue signals in to digital signals. In the microcontroller there are five pins r eserved for the ADC inputs. During the data transmission ADC functions plays a important role in interrupting the signal. An initialisation is required for the interrupt to perform any function in C- language.Init CAPTURE ( )The intrigue function is mainly used to measure the frequency and time period of the PWM wave form generated from the two legs J30 and J31 pins of the H-bridge converterInitTimer3 ( ) and InitTimer1 ( )To set initial time in the microcontroller for the capture function and timer 1 set the commencement time for the interrupt function happened in the UART communication system.InterruptsInterrupts are occurred only during the data transfer, when the transmission speed that is the baud rate is known operator the interrupts can be added to the system easily.in our project the baud rate is 19200.the main function of the interrupt is used synchronize time period of PWM with the speed loop and the current loop of the motor. In our project four different type of inter rupt service chip are used.They are ISR_ADCInterput ( )This interrupt is triggered when the ADC finishes its conversion and hence its get synchronized to the microcontroller PWM time base. From this all the application control code to be implemented in this interrupts service routine.ISR_T1Interput ( )The various information to the PC is transferred by using the UART communication link in this interrupts service routine. All the variables that are needed to be mentioned in this routine using standard C function sprint ( ).ISR_U1RXInterput( )Various information is transferred from the PC in to the C program. This routine concedes us to regulate the aspects of the program when it is running.ISR_IC1Interput( )It measures the speed value from timing data that are attained in the input capture module.FIGURE 14 The connection diagram for the speed control of Dc motor is shown aboveCHAPTER 55 Results and discussionAs discussed earlier the various functions of hardware components in this p roject, this section discusses the details regarding how the project deals with comparing and evaluating the results. Project has a series of steps each step is assigned with different operation techniques to execute the final results.5.1 Initial connection test between MPLAB IDE and Flexible inverted Board ab initio the system needs to be interfaced using the flexible inverter board. This operation is performed by conne