Dc Power Source Utilization Engineering Essay

Dc Power start Utilization Engineering EssayM each industrial operations entertain begun to require racy position apparatus in young years. Some mediocre voltage motor scrams and utility lotions require medium voltage and megawatt might level. For a medium voltage grid, it is trouble several(prenominal) to combine however wholeness mogul semiconductor switch directly. As a ending, a multilevel baron inverter twist has been introduced as an alternative in high major federal agencyfulness and medium voltage business offices. A multilevel inverter is a power electronic device create to synthesize a craved AC voltage from several(prenominal) levels of DC voltages.The concept of multilevel shifters has been introduced since 1975. The term multilevel began with the terzetto-level transpo charmr. Subsequently, several multilevel converter topologies have been developed. Plentiful multilevel converter topologies have been proposed during the last ii decades. Cont emporary research has set-aside(p) novel converter topologies and unique modulation schemes. Moreover, there argon ternion different major multilevel converter structures which ar cascaded H-bridges converter with dampen dc outsets, diode clamped (neutral-clamped), and flying capacitors (capacitor clamped) 1 Although the diode clamped multilevel inverter is comm al one and only(a) discussed in the literature, there has been considerable interest in the series connected or cascaded H-bridge inverter topologies 2. However, the elementary concept of a multilevel converter to achieve high power is to hire a series of power semiconductor switches with several beginninger voltage dc tooth roots to perform the power conversion by synthesizing a staircase voltage prosperform. Capacitors, batteries, and renewable energy voltage germs stinkpot be engagementd as the quadruple dc voltage sources 1.multilevel power conversion has become increasingly popular in upstart years due to advantages of high power quality waveforms, low electromagnetic compatibility (EMC) concerns, low permutation losses, and high-voltage capability. The primary disadvantage of multilevel power conversion technology is the large add together of semiconductor devices infallible. This does not fruit a signifi layaboutt cost maturation since lower-voltage devices whitethorn be utilize. However, an increase in gate drive hitchry and much elaborate mechanical layout atomic number 18 need 3.Project OverviewThis roll go away involve in the foundation and construction of a star bod 3-level H-bridge inverter apply the IGBTs. An H-bridge is an electronic move which enables a voltage to be utilize across a lodge in either direction. These tours allow DC motors to run forwards and chokewards. H-bridges ar available as integrated hitchs, or contri scarcee be built from discrete components.In this single physique H-bridge inverter circuit, the IGBTs atomic number 18 utilise as power devices that will be operated as a switch by applying control prognostic to gate terminal of IGBTs. The insulated gate bipolar combination transistor or IGBT is a three-terminal power semiconductor device, noted for high strength and fast switching.The softw are that will be used is MATLAB Simulink. Simulink is a technical tool for temperling, simulating and analyzing multido all important(p) dynamic systems. Its primary interface is a graphical hold on diagramming tool and a customizable set of stymy libraries.The Aims and ObjectivesThe aim of this objectify is to simulate a single phase 3-level H-bridge inverter (DC to AC converter) using the MATLAB Simulink and constructed it.The objectives of this project are as followsTo investigate the use of H-bridge inverter.To assemble using the software, circuits implementation, and troubleshoot for the hardware.To learn the operation of the single-phase 3-level inverter for software and hardware.CHAPTER 2LITE RATURE REVIEWInverterPower electronics converters may be classified into four categories based on the source and types of the want sidetrack characteristics as shown in underframe 1.1 belowOUTPUTACDCACINPUTRECTIFIERREGULATORSDCCHOPPERSINVERTERS see to it 2.1 Converter ClassificationDC-to-AC converter is k without crackn as inverter. The function of an inverter is to change a DC enter voltage to a symmetrical AC product voltage of desire order of magnitude and relative frequency. The variable product voltage could be fixed or variable at a fixed or variable frequency. Inverter foot be built in m two output portend phases which is normally use in practice like single phase inverter and three phase inverter. The implementation of the inverter circuit must to be involved in application of the power devices like SCR, MOSFET, IGBT, GTO, and Forced-Commutated Thyristor which is controlled to turning ON and turning-OFF in its operation as a converter. This inverter generally us e PWM control signal for producing an AC output voltage 3.Single Phase H-Bridge Inverter OperationThe H-Bridge Inverter or sometimes called just Bridge consists of four switches (see Figure 2.2). A boost converter is required as this system has no means of stepping up the input. Switches S1-S4, and S2-S3 make up two switch pairs. When S1and S4 are on, the output voltage is a confirmatory pulse, and when S2 and S3 are on, the output is a banish pulse. The phase sequence, frequency, output magnitude and harmonics can be controlled through appropriate switching devices, in accompaniment with other equipment.Figure 2.2 Single phase H-bridge inverterSingle Phase multilevel H-Bridges InverterThere are two types of multilevel H-bridge inverter that can be selected in this project which are classifyd dc source and single DC source. These two types have its pros and cons. The advantages of separated DC source areThe number of possible output voltage levels is more than twice the number of dc sources (m = 2s + 1).The series of H-bridges makes for modularized layout and packaging. This will enable the manufacturing process to be done more quickly and cheaply.while the disadvantage isSeparate dc sources are required for each of the H-bridges. This will limit its application to products that already have multiple SDCSs readily available.Each H-bridge cell requires an a discriminate(p) dc source. The isolated sources are typically provided from a transformer/rectifier arrangement, tho may be supplied from batteries, capacitors or photovoltaic arrays to add up the output voltages. This topology was patented by Robicon collection in 1996 and is one of the companies standard drive products.2On the other hand, for the single DC source multilevel H-bridge inverter, the advantage of this type of connection is only one DC tack is used. This will not limit its application to products. And the disadvantage of single DC source is transformer is needed to add up the output voltagesSeparated DC Source multilevel H-Bridges InverterA single-phase structure of an m-level cascaded inverter is illustrated in Figure 2.3. Each separate dc source (SDCS) is connected to a single-phase full-bridge, or H-bridge, inverter. Each inverter level can generate three different voltage outputs, +Vdc, 0, and -Vdc by connecting the dc source to the ac output by different combinations of the four switches, S1, S2, S3, and S4. To obtain +Vdc, switches S1 and S4 are turned on, whereas -Vdc can be obtained by turning on switches S2 and S3. By turning on S1 and S2 or S3 and S4, the output voltage is 0. The ac outputs of each of the different full-bridge inverter levels are connected in series such that the synthesized voltage waveform is the spirit of the inverter outputs. The number of output phase voltage levels m in a cascade inverter is defined by m = 2s+1, where s is the number of separate dc sources 1.Figure 2.3 Single-phase structure of a multilevel cascaded H-bridges i nverterAn example phase voltage waveform for a nine-level cascaded inverter and all H-bridge cell output waveforms are shown in Figure 2.4. In this thesis, all dc voltages are fictive to be equal. According to sinusoidal-liked waveform, each H-bridge output waveform must be quarter-symmetric as illustrated by V1 waveform in Figure 2.2. Obviously, no thus off the beaten track(predicate) harmonic components are available in such a waveform. To smear THD, all switching angles must be numerically calculated.Figure 2.4 waveform showing a nine-level output phase voltage and each H-bridge output voltage.One of the advantages of this structure is the number of possible output voltage levels is more than twice the number of dc sources (m = 2s + 1). The other advantage is the series of H-bridges makes for modularized layout and packaging. This will enable the manufacturing process to be done more quickly and cheaply. On the other hand, the main disadvantage of this topology is that separa te dc sources are required for each of the H-bridges. This will limit its application to products that already have multiple SDCSs readily available. The sources are typically provided from a transformer/rectifier arrangement, but may be supplied from batteries, capacitors or photovoltaic arrays.Single DC source Multilevel H-Bridges InverterReferred to Zhong Du1, Leon M. Tolbert, John N. Chiasson, and Burak -zpineci thesis entitled A Cascade Multilevel Inverter development a Single DC Source, a regularity is presented showing that a cascade multilevel inverter can be implemented using only a single DC power source and capacitors. Without requiring transformers, the scheme proposed allows the use of a single DC power source for examples a onslaught or a fuel cell stack while the stay n1 DC sources being capacitors.Figure 2.5 shows the Single DC source Multilevel H-Bridges Inverter. The DC source for the eldest H-bridge (H1) is a DC power source with an output voltage of Vdc, whil e the DC source for the second H-bridge (H2) is a capacitor voltage to be held at Vdc/2. The output voltage of the first H-bridge is denoted by v1 and the output of the second H-bridge is denoted by v2 so that the output of this two DC source cascade multilevel inverter is v(t) = v1(t)+v2(t). By opening and decision the switches of H1 appropriately, the output voltage v1 can be make equal to Vdc, 0, or Vdc while the output voltage of H2 can be made equal to Vdc/2, 0, or Vdc/2 by opening and closing its switches appropriately.Figure 2.5 Single DC source Multilevel H-Bridges InverterIGBTs Versus MOSFETsThe power MOSFET is a device that is voltage- and not current-controlled. MOSFETs have a positive temperature coefficient, stopping thermal runaway. The on-state-resistance has no theoretical limit, hence on-state losses can be far lower. The MOSFET besides has a consistency-drain diode, which is placeicularly useful in dealing with special free wheeling currents. All these advant ages and the comparative elimination of the current go after soon meant that the MOSFET became the device of choice for power switch forges.Then in the 1980s the IGBT came along. The IGBT combines the cross between the power MOSFET and a bipolar power transistor (see Figure 2.2). The IGBT has the output switching and conduction characteristics of a bipolar transistor but is voltage-controlled like a MOSFET. In general, this means it has the advantages of high-current discussion capability of a bipolar with the ease of control of a MOSFET. However, the IGBT unsounded has the disadvantages of a comparatively large current tail and no body drain diode. Early versions of the IGBT are too prone to latch up, but nowadays, this is pretty well eliminated. Another potential problem with some IGBT types is the negative temperature co-efficient, which could lead to thermal runaway and makes the analogueing of devices hard to effectively achieve. This problem is now being addressed in the latest generations of IGBTs that are based on non-punch through (NPT) technology. This technology has the same basic IGBT structure (see Figure 2.6) but is based on bulk-diffused silicon, rather than the epitaxial material that both IGBTs and MOSFETs have historically used 4.Figure 2.6 NPT IGBT cross sectionThe comparisons between MOSFETs and IGBTs are as belowTable 2.1 Comparisons between IGBTs and MOSFETsIGBTsMOSFETsCharacteristics kickoff duty cycle gloomy frequency (Narrow or small line or laden variations spunky-voltage applications (1000V)5kW output powerOperation at high junction temperature is allowed (100C)Long duty cyclesHigh frequency applications (200kHz)Wide line or load variationsLow-voltage applications (ApplicationsMotor control Frequency Uninterruptible power supply (UPS) Constant load, typically low frequencyWelding High comely current, low frequency (Low-power lighting Low frequency (Switch mode power supplies (SMPS) Hard switching above 200kHzSwitch mode power supplies (SMPS) ZVS below 1000 wattsBattery charging 4Applications of InvertersThere are many application of inverter available today. Some of the applications are as followsDC power source utilizationAn inverter converts the DC galvanising automobileity from sources such as batteries, solar panels, or fuel cells to AC electricity. The electricity can be at any required voltage in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltage.Grid tie inverters can feed energy back into the distribution network because they produce alternating current with the same wave shape and frequency as supplied by the distribution system. They can also switch off automatically in the event of a blackout.Micro-inverters convert direct current from individual solar panels into alternating current for the electric grid.Electric vehicle drivesAdjustable speed motor control inverters are currently used to power the traction motor in some ele ctric locomotives and diesel-electric locomotives as well as some onslaught electric vehicles and hybrid electric highway vehicles such as the Toyota Prius. versatile improvements in inverter technology are being developed specifically for electric vehicle applications. In vehicles with regenerative braking, the inverter also takes power from the motor (now acting as a generator) and stores it in the batteries.Uninterruptible power suppliesAn uninterruptible power supply (UPS) uses batteries and an inverter to supply AC power when main power is not available. When main power is restored, a rectifier is used to supply DC power to recharge the batteries.Variable-frequency drivesA variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the list component, variable-frequency drives are sometimes called inverter drives or just inverters.Induction heatingInverters convert low frequency main AC power to a higher frequency for use in induction heating. To do this, AC power is first rectified to provide DC power. The inverter then changes the DC power to high frequency AC power.CHAPTER 3METHODOLOGYIntroductionThis chapter exposes the proposed method of this project to built single phase multilevel H-bridge inverter. This project can be divided into two main parts of study which are software and hardware implementation. For the software part, the software used is PIC24 Compiler that used to do the programming for the microcontroller part and MATLAB to do the simulation of the inverter circuit in advance implemented it in hardware. In addition, Proteus 7 Professional is also used to simulate the number one wood circuit before do the hardware. The compact of the project is shown in Figure 3.1.Software Part Prepared(Microcontroller) hardware Part PreparedTroubleshootingInterfacingResultFigure 3.1 The project summary form of the H-Bridge Inverter SystemThe H-Bridge inverter system can be divided into three main stages that were constructed. It is consists ofMicrocontrollerPower electronics driverPower electronics inverterEach part was treated as a separate functional block system. Figure 3.2 below shows the block diagram of how each stage of the inverter system are organized. Power electronic driver circuit and microcontroller stage is the low voltage side and power electronics inverter circuit is the high voltage side.DC electromotive force InputAC OutputPower Electronics Inverter spellMicrocontrollerPower Electronic Driver CircuitFigure 3.2 The block diagram of the inverter systemMicrocontrollerMicrocontroller is a computer-on-a-chip optimised to control electronic devices. The microcontroller chip used for this project is PIC16F877A. In this project, microc ontroller is used to develop the triggering signal for the IGBTs and interfacing to the single phase inverter circuit as a control signal for the gate driver.To implement the microcontroller part, the program for triggering the IGBTs was written in assembly speech communication using the PIC C Compiler. It is written in the text editor in chief or notepad called as source code. It also can be written directly in the PIC C Compiler. Then the file save is *file.c file. After the program is successfully compiled, the *file.hex file was generated. The hex file was tested by doing the simulation in the Proteus 7 Professional to see the output generated from the program. After got the correct output, the *file.hex file then was uploaded in the PIC16F877A using the PIC programmer. The process of implementing the microcontroller is shown in Figure 3.3. This microcontroller part is the first part that was implemented in hardware.Figure 3.3 The process of implementing the microcontrollerP ower Electronics DriverA driver is an electronic component used to control another circuit or other component, such as a high-power transistor. opposed the bipolar transistor, which is current driven, IGBTs, with their insulated gates, are voltage driven. It is allows user to speed up or slow down the switching speeds according to the requirements of the application.The control circuitry supplied low current driving signals that are attendenced to controller-ground. A logic one signal was employ to its gate with respect to its source to turn on an IGBT switch, and this signal needs to restrain sufficient power. These requirements can not be met by the control circuit. Figure 3.5 shows a diagram of how signals need to be applied to IGBT switches for effective operation.Figure 3.4 Control signals need to be applied to the gate with respect to the sourceThe driver chose is IR2110 which is a dual driver. The IR2110 High Voltage Bridge Driver is a power integrated circuit that is desi gned to drive two insulated gate devices. The typical connection of the driver is shown in Figure 3.5. The two channels of the IR2110 are completely free of one another. The HO output is controlled by the HIN input, and the LO output is controlled by the LIN input. The two inputs of the IR2110 are logically coupled to the shutdown (SD) pin through an AND gate. If HIN and LIN both go high, then the IR2110 will be shut down until one or both inputs go low. This measure helps prevent the catastrophic situation where both Q1 and Q2 turn on at the same time and piffling circuit the input source. 5Figure 3.5 Typical connection of IR2110 High Voltage Bridge DriverIsolation using the optocouplerAn optocoupler or sometimes refer to as optoisolator allows two circuits to exchange signals yet remain electrically isolated. This is normally accomplished by using light to relay the signal. The standard optocoupler circuits design uses a LED shining on a phototransistor. The signal is applied to the LED, which then shines on the transistor in the ic. The optocoupler circuit is shown in Figure 3.6 below. In this project, the optocoupler is used as the source and destination are at very different voltage levels, where the source is the microprocessor which is operating from 5V DC but it being used to control the IGBTs which is switching at higher voltage. In such situations the link between the two must be an isolated one, to protect the microprocessor from overvoltage damage. The optocouplers can be used with following advantages for driving high side IGBT in any topologyThey can be used to give a very high isolation voltageSignals from DC to several MHz can be handled by opto-couplers.They can be easily interfaced to Microcomputers or other controller ICs or any PWM IC.Figure 3.6 Optocoupler circuitThe circuit of low side voltage which consists of PIC, driver and optocoupler was first constructed in the Proteus 7 Professional to see the output generated to be compared with the hardware results. The circuit is as in Figure 3.7 below.Figure 3.7 Low side voltage simulationPower Electronic InverterThe power electronics inverter part is the main part of the system. This is because this circuit will perform the conversion from DC to AC. The circuit consists of four IGBT that act as a switch, DC source and also the load. Figure 3.8 shows a diagram of the H-Bridge power electronics inverter stage.Figure 3.8 H-Bridge power electronics inverter stage.But for this project, the inverter circuit used is the 3-level H-bridge inverter circuit. The circuit was first constructed in the MATLAB as in Figure 3.9 and the simulation of the circuit was done to see the result of simulation.Figure 3.9 3-level H-bridge inverter circuit constructed in MATLABThe block parameter for the IGBTs was set as in Figure 3.10. The switching frequency used for this circuit is 50Hz. So, the stage of waveform can be calculated as below faulting frequency, f = N / PfFundamental period, Pf = 1 / f fundamental = 1/ 50 = 0.02sFigue 3.10 The block parameter setting for the IGBTsIn addition, the phase delay or switching times of the IGBTs were also set. Table 3.1 below shows the switching time of the IGBTs. After the simulation was success, the circuit of single 3-level H-bridge inverter was constructed.Table 3.1 The switching time of the IGBTsIGBTsSwitching periodIGBT 1 and IGBT 310 ms ()IGBT 2 and IGBT 40 ms (0 )IGBT 5 and IGBT 77 ms (/7)IGBT 6 and IGBT 83 ms (/3)For the switch, IRGB10B60KDPBF IGBT was selected for this design. It is very important to choose the correct switches for the inverter circuit because the performance of the design is directly depends on this. This IGBT was chosen because it has ultra fast recovery diode along, it offered benchmark capacity for motor control and excellent current sharing in parallel operation. In addition the IGBT was selected as they are able withstand the power rating of the inverter. Table 3.2 shows some of the features of the selected IGBT.Table 3.2 The features of IRGB10B60KDPBF IGBTCharacteristicsValueDrain to Source Voltage (Vds)600VDrain Current (Id)12ARise Time20nsFall Time23nsShort Circuit Capability10sFigure 3.4 3-level H-bridge inverter circuit