Inverter Design For Three Phase Induction Machine-Physics-Report, Study Guides, Projects, Research of Physics

Download Inverter Design For Three Phase Induction Machine-Physics-Report and more Study Guides, Projects, Research Physics in PDF only on Docsity! ii Table of Contents 1 Inverter Design for three phase Induction Machine ................................................... 1 1.1 Inverter: ................................................................................................................ 1 1.2 Three Phase Induction Machine: .......................................................................... 2 1.3 Intelligent power Module: .................................................................................... 3 1.3.1 Introduction: .................................................................................................. 3 1.3.2 Structure of Intelligent Power Modules: ....................................................... 3 1.3.3 Advantages of Intelligent Power Module: .................................................... 4 1.3.4 Controlling the Intelligent Power Module: ................................................... 4 2 Our Task: .................................................................................................................... 5 2.1 Transformer design: ............................................................................................. 5 2.1.1 Specification: ................................................................................................ 5 2.2 Power Supply ....................................................................................................... 7 2.2.1 Rectifier: ....................................................................................................... 7 2.2.2 Bridge Rectifier:............................................................................................ 7 2.2.2.1 Current Flow in the Bridge Rectifier: .................................................... 8 2.2.3 RC Filter: ...................................................................................................... 8 2.2.4 Voltage Regulator: ........................................................................................ 9 2.2.4.1 Purpose of Voltage Regulator: .............................................................. 9 2.2.4.2 Regulator Circuit: .................................................................................. 9 2.2.4.3 Proteous Circuit: .................................................................................. 10 2.2.4.4 PCB Layout: ........................................................................................ 10 2.3 Isolation Board: .................................................................................................. 11 2.3.1 Proteous Circuit: ......................................................................................... 11 2.3.2 PCB Layout:................................................................................................ 11 docsity.com iii List of Figures Figure 1-1 Inverter Input/output ................................................................................................................ 1 Figure 1-2 Main Diagram Of The Inverter Design .................................................................................... 2 Figure 1-3 Optocoupler signals ................................................................................................................... 4 Figure 1-4 Intelligent Power Modul ............................................................................................................ 4 Figure 2-1 Transformer with 4 Secondaries............................................................................................... 7 Figure 2-2 Bridge Rectifer. .......................................................................................................................... 7 Figure 2-3 Forward biased for positive half cycle. .................................................................................... 8 Figure 2-4 Forward biased for negative half cycle. ................................................................................... 8 Figure 2-5 RC Filter. .................................................................................................................................... 8 Figure 2-6 Effect of RC Filter. ..................................................................................................................... 9 Figure 2-7 IC Voltage Regulator. ............................................................................................................... 9 Figure 2-8 Voltage Regulator Circuit. .......................................................................................................10 2-9 Proteus circuit of Regulated Power Supply. .......................................................................................10 2-10 PCB layout of Power Supply Circuit. ................................................................................................10 Figure 2-11 OptoCouplers ..........................................................................................................................11 Figure 2-12 Proteous circuit of Isolation Board ........................................................................................11 Figure 2-13 PCB Layout Of Isolation Board.............................................................................................12 docsity.com 2 Figure 1-2 Main Diagram Of The Inverter Design 1.2 Three Phase Induction Machine: Introduction: An induction or asynchronous motor is a type of AC motor where power is supplied to the rotor by means of electromagnetic induction. These motors are widely used in industrial drives, particularly poly phase induction motors, because they are rugged and have no brushes. Single-phase versions are used in small appliances. Their speed is determined by the frequency of the supply current, so they are most widely used in constant speed applications, although variable speed versions, using variable frequency drives are becoming more common. Operation: In both induction and synchronous motors, the stator is powered with alternating current and designed to create a rotating magnetic field which rotates in time with the AC oscillations. In a synchronous motor, the rotor turns at the same rate as the stator field. By contrast, in an induction motor the rotor rotates at a slower speed than the stator field. docsity.com 3 Therefore the magnetic field through the rotor is changing . The rotor has windings in the form of closed loops of wire. The rotating magnetic flux induces currents in the windings of the rotor as in a transformer. According to Lenz's law the rotor windings will try to oppose the cause of production of induced current in the rotor. The cause of induced current in the rotor is the rotating stator magnetic field, so to oppose this the rotor will start to rotate in the direction of the rotating stator magnetic field to make the relative speed between rotor and rotating stator magnetic field zero, thus the motor will start. For these currents to be induced, the speed of the physical rotor must be lower than that of the stator's rotating magnetic field ( )or the magnetic field would not be moving relative to the rotor conductors and no currents would be induced. As the speed of the rotor drops below synchronous speed, the rotation rate of the magnetic field in the rotor increases, inducing more current in the windings and creating more torque. The ratio between the rotation rate of the magnetic field as seen by the rotor (slip speed) and the rotation rate of the stator's rotating field is called "slip". Under load, the speed drops and the slip increases enough to create sufficient torque to turn the load. For this reason, induction motors are sometimes referred to as asynchronous motors. 1.3 Intelligent power Module: 1.3.1 Introduction: Mitsubishi Electric introduced the first full line of Intelligent Power Modules in November, 1991.Mitsubishi Intelligent Power Modules (IPMs) are advanced hybrid power devices that combine high speed, low loss IGBTs with optimized gate drive and protection circuitry. Highly effective over-current and short-circuit protection is realized through the use of advanced current sense IGBT chips that allow continuous monitoring of power device current. System reliability is further enhanced by the IPM’s integrated over temperature and under voltage lock out protection. 1.3.2 Structure of Intelligent Power Modules: Mitsubishi Intelligent Power Modules utilize many of the same field proven module packaging technologies used in Mitsubishi IGBT modules. Cost effective implementation of the built in gate drive and protection circuits over a wide range of current ratings was achieved using two different packaging techniques. Low power devices use a multilayer epoxy isolation system while medium and high power devices use ceramic isolation. IPM are available in four power circuit configurations, single (H), dual (D), six pack (C), and seven pack (R). Figure 6.1shows the power circuit configurations. docsity.com 4 Figure 1-3 Optocoupler signals 1.3.3 Advantages of Intelligent Power Module: IPM products were designed and developed by reducing design, development, and manufacturing costs as well as providing improvement in system performance and reliability over conventional IGBTs. Others include increased system reliability through automated IPM assembly and test and reduction in the number of components that must be purchased, stored, and assembled. Often the system size can be reduced through smaller heat sink requirements as a result of lower on-state and switching losses. All IPMs use the same standardized gate control interface with logic level control circuits allowing extension of the product line without additional drive circuit design. Finally, the ability of the IPM to self protect in fault situations reduce the chance of device destruction during development testing as well as in field stress situations. 1.3.4 Controlling the Intelligent Power Module: IPMs are easy to operate. The integrated drive and protection circuits require only an isolated power supply and a low level on/off control signal. A fault output is provided for monitoring the operation of the modules internal protection circuits. Figure 1-4 Intelligent Power Modul docsity.com 7 Figure 2-1 Transformer with 4 Secondaries. 2.2 Power Supply 2.2.1 Rectifier: A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification. Rectifiers have many uses, but are often found serving as components of DC power supplies and high-voltage direct current power transmission systems. Rectification may serve in roles other than to generate direct current for use as a source of power. 2.2.2 Bridge Rectifier: A bridge rectifier makes use of four diodes in a bridge arrangement to achieve full-wave rectification. This is a widely used configuration, both with individual diodes wired as shown and with single component bridges where the diode bridge is wired internally. Figure 2-2 Bridge Rectifer. docsity.com 8 2.2.2.1 Current Flow in the Bridge Rectifier: For both positive and negative swings of the transformer, there is a forward path through the diode bridge. Both conduction paths cause current to flow in the same direction through the load resistor, accomplishing full-wave rectification. While one set of diodes is forward biased, the other set is reverse biased and effectively eliminated from the circuit. Figure 2-3 Forward biased for positive half cycle. Figure 2-4 Forward biased for negative half cycle. 2.2.3 RC Filter: The simple process of rectification produces a type of DC characterized by pulsating voltages and currents. Depending upon our needs, this type of DC current may then be further modified into the type of relatively constant voltage DC characteristically produced by such source as batteries. Figure 2-5 RC Filter. docsity.com 9 Figure 2-6 Effect of RC Filter. 2.2.4 Voltage Regulator: 2.2.4.1 Purpose of Voltage Regulator: Voltage regulators are used in power supplies to regulate or eliminate variations from DC voltage. This stage is the important part of Power Supplies; it regulates the DC voltages required at the output of power supply. If these regulators don’t work properly, our sensitive electronics equipments may blow off. 2.2.4.2 Regulator Circuit: IC voltage regulators are versatile and relatively inexpensive and are available with features such as a programmable output, internal short-circuit current limiting and floating operation for high voltage applications. While filters can reduce the ripple from power supplies to a low value, the most effective approach is a combination of a capacitor input filter used with a voltage regulator. The capacitor input filter reduces the input ripple to the regulator to an acceptable level. Most regulators are integrated circuits and have three terminals, an input terminal, an output terminal, and a reference (or adjust) terminal. The input to the regulator is first filtered with a capacitor to reduce the ripple to < 10%, the regulator reduces the ripple to a negligible amount, in addition, most regulators have an internal voltage reference, short circuit protection, and thermal shutdown circuitry. Three terminal regulator designed for fixed output voltages require only external capacitors to complete the regulation portion of the power supply, as shown in figure. Filtering is accomplished by a large value capacitor between the input voltage and ground. An output capacitor is connected from the output to ground to improve the transient response. Figure 2-7 IC Voltage Regulator. docsity.com