Control Of A Switched Reluctance Motor Engineering Essay

Control Of A Switched Reluctance Motor Engineering Essay The main objective of this chapter is to spot the light on the practical performance of some form of control on an actual switched reluctance motor in preference to merely theoretical method including simulation and modelling. Moreover, the design of the controller involves reducing the noise. The crucial motivation for this is to enhance new expertise, sensibly regarding circuit design and construction the use of a Programmable interface controller (PIC). A switched reluctance motor (SRM) has been appeared since the nineteenth century, but the renewal of this motor has been to discover a high-power switched device [13]. The earlier motor was facing a controversial issue in their control where the power electronic switching was very expensive and has many drawbacks. The Switched Reluctance Motor (SRM) is an electromagnetic, rotary machine in which torque is produced by the tendency of its movable part to move to a position where the inductance of the excited winding is maximized [12]. Furthermore, (SRM) has been proposed for variable speed applications [13]. In general a salient-pole synchronous machine without field excitation or permanent magnet is called a reluctance machine. From the general definition (SRM) is classified as a synchronous machine, but has different construction. These differences are both stator and rotor have salient poles. However, the stator has wound field coils but the rotor has no coils or permanent magnet. Moreover, the stator has higher number of poles or (tooth) than the rotor. While each pole in the rotor is excited by the opposite pole in the stator due to a sequence of current pulses which produce magnetic field on each stator poles. The Switched Reluctance Motor (SRM) can be more capable for variable speed than AC and DC motor. Since it is simple, robust, has a high efficiency and high power density [3, 10, 12]. Figure 1.1: two- two poles SRM [12] Over the past 30 years the power electronics growth has made the exploit of the characteristics of reluctance machines sufficiently well. Consequently, several successful products are now manufactured. The rotation of the motor depends on the angle between the rotor poles and the stator poles where the current is switched on or off to each poles in the stator where the position of the rotor is very significant. For the motoring principle example, two- two poles (SRM) where stator has two poles with two wound field coils connected in series and two poles in the rotor without magnets or windings and free to rotate as it shown in figure 1.1. If the rotor poles edge is started to be aligned, the current is switched on. Consequently, the inductance is increased and the torque in the rotor is occurred to pull the rotor in clockwise direction. The direction of the rotation is addressed by the current. The current is switched off; when the rotor poles are fully aligned with the stator poles that make the rotor free to move. However, if the current is not switched off the torque at the fully aligned is become negative that produces an attraction between the poles where the negative torque and positive torque cancel each other [12]. The ideal current waveform is therefore a series of pulses synchronized with the rising inductance intervals. The cycle of torque production associated with one current pulse is called a stroke.[12] As a result, to increase the resolution more teeth can be add to the stator and the rotor. From the instantaneous electromagnet torque equation which was derived by T.J.E.Miller(2001) [12] Te = i2/2 dL/dÃŽÂ ¸ that shows the torque is proportional to the square of the current. Therefore, the current is always unipolar. However, at the end of each stoke the voltage must be reversed to return the flux linkage to zero. The power switching IGBT, GTO and MOSFET or any other switching devices can be used in the power electronic topologies [3]. These switches are used to open and close the exiting power in the stator winding. 1.5. Applications of SRM Since the SRM has a significant characteristic operation and design which shows many advantages and makes them suitable for various applications. R.Krishnan (2001) [10] shows the wide range of applications. For example, plotter drive, air-handler motor drive, hand fork lift/ pallet truck motor drive, door actuator and washers and dryers machine, those applications are low power applications where the drives are less than 3hp. Moreover, the medium power applications range is less than 300kw such as industrial general purpose drive, train air conditioning drive and mining drive. However, the SRM did not find much attention by the manufacturers in this range of power. The high power drives are still under study for drives up to 1000hp for fan and pump applications where the converter is very competitive. The high speed applications such as screw rotary compressor drives, centrifuge for medical applications, and aerospace applications the SRM is a perfect option for them due to the small size of the rotor and high power density. Some efforts of study are in Mild Hybrid Vehicles that is reported by (Watterson, P.A. ; et al) [17] in 2008. 1.6 Research area Since the SRM has appeared and has disadvantages such as reduction of acoustic noise and torque ripple. According to the noise and vibration sources can be classified into four main categories: magnetic, mechanical, aerodynamic, and electronic. The classification was done by R.Krishnan (2001) [10] as it shows in figure 1.2. Most researches are based on the design of the motor or in the controller to improve the motor performers and reduce the noise. Iqbal Husain (1994) [8] discusses the effect of the high ripple toque which causes vibration and acoustic noise. The case was in driving SRM for low speed and high performance applications by a new PWM strategy current control. The method was based on optimum profiling of the phase current during an extended overlapping conduction period of two phases. The result shows a smooth operation with minimum torque pulsations by controlling the current profiling. Moreover, other studies were in magnetic radial force as M. N. Anwar (2000) [1] show s the lower noise is occurred when the dominant mode frequencies is high. As a result the research has experimented a proposed design considerations to a 4-phase, 8/6 (1-repetition) and a 3-phase, 12/8 (2-repetition) 1.0 kW SRM with low acoustic noise requirement. The results of the proposal design shows that the noise level has been reduced; however, a 3-phase SRM is noisier than a 4-phase SRM. There are other research was on reducing the noise by Adding extra winding to the phase winding to reduce magnetic stress during commutations with Two stage power converter. Adding extra winding to the phase winding in 6/4 SRM with Two stage power converter shows a significant improvement in the efficiency and reduce in the vibration and noise [16]. The electronic sources of noise occur by reason of the harmonics of voltage and current. The significant research is reported by (Lecointe J.P; et al) in (2004) [11]. The research was in adding an auxiliary winding to the model of a BDFRM (brus hless doubly-fed reluctance machine) to shows that the additional winding has a benefit in reducing the noise in SRMs where a specially derived current is injected to create a suppression force. The BDFRM is used to analyse the equivalent circuit where the equivalent circuit of the model is similar to SRM. However, the process still needs to be complete using two current sources. Figure 1.2: sources of noise in electrical machines [10] Advantages and disadvantages of 3 basic power electronic circuits There are many power electronic topologies that is used for SRM depends on the machine phase configurations. R. Krishnan (2001) [10], figure 1.3, has classified the power converters for switched reluctance machines. The simple three topologies are: Figure 1.3: Classification of power converters for SRM [10] 1.7.1. Single-Switch-per-Phase Circuits (Split dc supply converter) The basic operation of this topology, figure 1.4, is to split the reverse dc power supply into two capacitors. The phase voltage is half the dc voltage when the switch is on and negative half voltage when the switch is off. Consequently, this configuration is a disadvantage. Moreover, the maximum speed and the output power are half the rated while the current and the voltage are half. This topology is only used for low-cost application due to the high power losses. However, the advantages of this topology are: simple and less cost. [3, 10] Figure 1.4: Single-Switch-per-Phase Circuits (Split dc supply converter) [10] 1.7.2. Single-Switch-per-Phase Circuits (Bifilar type) The basic operation of this topology uses a bifilar winding, figure 1.5, with the motor winding to regenerate the stored energy to the supply that the phase winding is connected in series with the switch, and the diode is connected in series with the bifilar winding. The reflected energy is an advantage for this topology in some applications, where the transistor voltage is much higher than the supply voltage. However, the cost increases as the extra winding is added to the motor and the complex design of the power electronic. Moreover, the power density of the motor reduces because of the bifilar winding. [3,10] Figure 1.5: Single-Switch-per-Phase Circuits (Bifilar type) [10] 1.7.3. Two-switch/phase Asymmetric Bridge Converter From the half bridge topology that is illustrated in figure 1.6. if both Q1 and Q2 are turned on the apply voltage at the winding is equal to the supply voltage. However, if both Q1 and Q2 are turned off the apply voltage at the winding is equal to a negative supply voltage where D1 and D2 to avoid the freewheel currents. The advantages of this topology that it can give a negative voltage to reduce the torque ripple refer to noise for a high performance SRM drive system and it can be used for generator or motor operations. The disadvantages more control is needed, more fault in the switching [3, 10, 12]. Figure 1.6: Two Switched / Phase Asymmetric Bridge Converter [12] 1.8 Speed and Position Controller The switched-reluctance motor is basic control system form of a torque-controlled drive as compared in performance to a D.C motor (separately-excited). Commonly, controlled speed or even position is the most requirements. The SR motors speed increases if torque is still produced. As the D.C. drive the torque of SR motor controller is included within a speed regulating loop. The rotor position sensor, which is the encoder, is used as a feedback to derive the speed of the motor readily as it shown in figure 1.7. From the figure it can be seen that an additional feedback is introduced to achieve the position control of the SRM [3]. Figure 1. 7: basic speed and position controller for SRM [3] Aims and Objectives The aims of the project are to design, build and test a power electronic circuit for Switched Reluctance motor (SRM) using Bifilar type. The objectives are as following: Understand the operation of two- two poles SRM to realise the behavior of the motor and their characteristic. We can know from their characteristic how to make the motor spin and the control techniques that is used for them. Select and Design Power Electronic Circuit can help to active a high efficiency, low noise and low cost. Test Power Electronic Circuit with Resistive Load: to find the advantages and disadvantages of the circuit when the resistive load is applied to the motor. Design, Build and Test current limiting circuit where the current limitation can achieve low torque rebel. From the low torque rebel the noise can be decrease. Rotate motor using direct feedback where the position of the rotor is important to detect the moment of switching on and off. Study and understand PIC 18F 46K20. Program PIC to control SR Motor by designing a simulation using the MATLAB or other programmes. Chapter 2 Choosing power electronic component 2. Overview Over the time motor control has a significant growth in the industrial control where digital signal processors together with external hardware and appropriate software are used widely. In order to control the motor the switching device should switch on and off according to the position of the motor rotor and the apply current to the stator winding. The aim of this chapter is to highlight the details of the components that were used in the controller design. 2.1 Technical operation of Simple SRM The simple SRM has 2 poles in the stator and 2 poles in the rotor, figure 1 which the stator iron core has square shape with two winding in the upper side opposite the poles. Both stator and rotor are salient poles where the free spinning rotor is placed between the stator poles. In order to spin the rotor, stator poles are energised by the winding when the rotor poles are unaligned with stator poles. The inductance increased and the torque is produced as the rotor approaches the aligned. At this point the stator winding is demagnetised allows the rotor free to spin. The time of the energised and de-energised of the motor windings depend on the rotor speed. Figure 2.1: (a) Simple SRM 2/2 poles with bifilar winding[12] 2.3 Winding connections The motor has a bifilar winding to build up the current in the stator quickly, figure 1, which facilitates the higher torque and magnetic flux densities occurring. As a result the stored energy regenerated to the supply that the phase winding is connected in series with the switch device. This leaded to three achievable connections, figure 2, for bifilar winding. Figure 2.2: Possible winding connections The first connection shows the parallel connection that has a resistance connected in parallel to the motor windings to reduce the power losses when the switch is off. This connection has the main disadvantage due to the high loss. The second connection shows series connection that two switching devises are used which increase the cost of the design. However, this topology is the most common one for SRM according to reduce the switching heat losses, protections and their control flexibility that is handling the phase current and the machines acoustic noise. The third connection is the most cost effective and easier to control for the simple SRM figure 2. Moreover, it is offering the zero voltage supply as a reference for all power switching that make it suitable for low- voltage systems. Simply this configuration operates as it shows in figure 2.3, When the current of phase-A is turned off by removing the base drive signal to T1, the induced EMF in the winding is of such polarity that D1 is forward biased. This leads to the circulation of current through D1, the bifilar secondary winding, and the source, thus transferring energy from the machine winding to the source. The various timing waveforms of the circuit are shown in Figure 2.3. During current turn-off, the applied voltage across the bifilar secondary winding is equal to the dc link voltage. The voltage reflected into the main winding is dependent upon the turns ratio of the windings. Considering the turns ratio between the main winding in series with the power switch and the aux iliary winding in series with the diode as a, the voltage across the power switch is VT 1 = Vdc + aVdc =(1 + a)Vdc This shows that the voltage across T1 can be very much greater than the source voltage. One switch per phase comes with a voltage penalty on the switch. The volt ampere (VA) capability of the switch will not be very different for one switch compared to two switches per phase circuit. [10] Figure 2.3: (a) Converter for an SRM with bifilar windings; (b) operational waveforms of bifilar converter. [10] Thus, Figure 4 shows the primary plan for designing the current limiting circuit for the third connection of SRM and each block are explained next. Figure 2.4 basic configurations for current limiting 2.4. Power switching component Nowadays semiconductor and electronic switching devices offer a significant performance to control the electrical motors. Moreover, their size and cost make them more convenient to use in the motor control. The electronic devices has a significant role to control SRM where the switching on and off for the voltage is the major role to control the SRM with high performance. As a result, the main electronic devices that can be used are field effect transistors. There are two types of the field-effect transistor J-FET and MOSFET (see the appendix figure 3) [4]. The MOSFET has taken a widely role as a best choice to the simple SRM for many reasons that is discussed later in this chapter. 2.4.1 N-channel power MOSFET (STP36NF06) Simply the MOSFET is a metal-oxide-semiconductor field effect transistor where the MSFET has a significant characteristic [2]. The characteristic of N-channel MOSFET shows a significant use in switching. The structures of the MOSFET are shown in figure 5 where the MOSFET consist of Si P material substrate, two N material substrate that one is the source and the other is drain, and between them there is an insulator Sio2 and at the top metal conductor which is known as a gate. The length (L) below the gate and between the source and the drain is known as a channel. Fundamentally, the MOSFET output current is proportional to the charge in the semiconductor material by the control electrode[15]. Figure 5 MSFET structures [6] The MOSFET is used as a switching device to provide a high speed switching. The significant advantages of the field-effect transistor are: Higher operation temperature. Lower switching leakage. High input impedance. Low noise. Lower power dissipation during switching. In addition, The N-channel MOSFET has advantages such as ease to use for high frequency switching and simpler to control where the MOSFET gate drive do not require a continuous current to switch ON. When the MOSFET is needed to switch ON positive threshold voltage is needed to apply to the gate drive and Zero current to completely switch off. Moreover, the N-channel MOSFET has higher density integration and possible in rapid reduction in capacitances. [2]. MOSFET (STP36NF06) gate requires drive properly the later components are used to limit the current and the gate signal for the MOSFET. The gate drive is a power amplifier that accepts a low power input from a controller devices and generate the appropriate high current gate drive for a power MOSFET[4]. 2.5. Bipolar junction Transistor Transistors are considered one of the main elements of semiconductors that have been discovered in modern times. Transistors are used in the amplifiers of electrical signals and electronic switching, which have helped a number of factors such as small size, ease in manufacturing, cost effective and consume less power to extend significantly. Figure 2.6 (a) transistor structures (b) npn and pnp structures 2.5.1. ZTX 653 NPN transistor The NPN transistor is a type of bipolar transistors known as a medium power transistor. The NPN ZTX 653 transistor has interesting features that make it suitable for the push pull topology and amplifier topology (pre totem pole connections). The features of NPN ZTX 653 transistor are [6] * 100 Volt VCEO * 2 Amp continuous current * Low saturation voltage * Ptot=1 Watt 5.5.2. ZTX 753 PNP transistor The PNP transistor is another type of bipolar transistors that is used in the push pull topology. The PNP ZTX 753 transistor is suitable to employ in the push pull topology (Totem Pole) according to their features. Their features are [6] * 100 Volt VCEO * 2 Amp continuous current * Low saturation voltage * Ptot=1 Watt Figure 2.7: npn and pnp characters 2.5.3 Gate drivers (Totem Pole) This type of connection is known as a discrete drivers or push pull drives which is in common use today. Figure 2.8 shows the complimentary arrangement pair bipolar NPN and PNP emitter configuration. Moreover, the N-channel and P-channel MOSFT can be employing for totem pole connection. However, the N-channel and P-channel MOSFT driver suffers from shoot through current, caused by the threshold voltage overlap during ON and OFF transitions, resulting in increased drive power requirements [9]. Figure 2.8: push pull configuration The bipolar Totem Pole, figure 2.8, is non-inverting and offers no voltage gain to improve the pre-driver rise or fall times. It does provide current gain to reduce the driver impedance to speed the charge and discharge of the device capacitances. Once the input capacitances are charged and the power device has been switched, the driver does not require holding current. It has medium speed and does not perform well at higher conversion frequencies [9]. This circuit uses a complementary pair of transistors similar betas and power rating one is an npn power Darlington, and the other is a pnp power Darlington. When a high voltage (e.g., +15 V) is applied to the input, the upper transistor (npn) conducts, allowing current to pass from the positive supply through the motor and into ground. If a low voltage (0 V) is applied to the input, the lower transistor (pnp) conducts, allowing current to pass through the MOSFET gate from ground into the negative supply terminal.[14] 2.5.4. Common emitter amplifier (inverter) This configuration is a simple electronic circuit that is used to boost and invert the low signal. Figure 2.9 shows the circuit that contain a high resistance value with NPN transistor. The low signal is switch on and off the transistor where the resistance is limiting the current that apply to the transistor. This topology is used to boost and invert the output of signal processing unit to appropriate the signal that can switch the MOSFET as it will be discussed in the following point. Figure 2.9 common emitter configuration 2.6. Current control and limiting The winding current is controlled inorder to be not more than 8A. When the MOSFET is switched ON without any current limiting circuit, the current shoots up without any control. As a result, the technique for current limiting is arranged as follows When the winding current is less than 8A the MOSFET switches ON. When the winding current is exceeds 8A the MOSFET switches OFF. Therefore for appropriate current control, square wave signal is applied to the gate of the MOSFET. The frequency of input signal at the gate of the MOSFET is take into account to make the MOSFET switch properly with regard to the above current control arrangement. In order to do that feedback from the source of the MOSFET is carried to non-inverting terminal of the comparator. Figure 10 shows the operational waveform of the MOSFET. It can be seen that, the MOSFET needs to switch off when the voltage at inverting input of the comparator reaches 0.8V and switch on when the voltage is zero. Moreover, the reference voltage is 0.8 volt from the voltage divider law when a 0.1ÃŽÂ © resistance is connected to the source of the MOSFET. The 555 timer can offer the control of MOSFETs switching frequency. Figure 2.10: the expected waveforms from the design. 2.6.1 Timer NE555P The 555 timer IC is an incredibly useful precision timer that can act as either a timer or an oscillator. In timer mode is known as monostable mode the 555 simply acts as a one-shot timer; when a trigger voltage is applied to its trigger lead, the chips output goes from low to high for a duration set by an external RC circuit. In oscillator mode is known as astable mode the 555 acts as a rectangular-wave generator whose output waveform (low duration, high duration, frequency, etc.) can be adjusted by means of two external RC charge/discharge circuits.[14] In this project the monstable circuit is highlighted due to it has one stable state. Figure 2.11 (a) monostable configuration of timer 555 (b) monostable operations[14] In the monostable configuration, figure 2.11(before a trigger pulse is applied) the 555s output is low, while the discharge transistor in on, shorting pin 7 to ground and keeping C discharged. Also, pin 2 is normally held high by the 10-k pull-up resistor. Now, when a negative-going trigger pulse (less than 1à ¢Ã‚ Ã¢â‚¬Å¾3VCC) is applied to pin 2, comparator 2 is forced high, which sets the flip-flops Q_ to low, making the output high (due to the inverting buffer), while turning off the discharge transistor. This allows C to charge up via R1 from 0 V toward VCC. However, when the voltage across the capacitor reaches 2à ¢Ã‚ Ã¢â‚¬Å¾3VCC, comparator 1s output goes high, resetting the flip-flop and making the output low, while turning on the discharge transistor, allowing the capacitor to quickly discharge toward 0 V. The output will be held in this stable state (low) until another trigger is applied [14]. According to the operation of the monstable the pulse width can be modified by changing the value of R1 and C. T= 1.11 R1C Thus, to obtain capable functioning of the circuit the variable resistance R1 with a maximum value 100KÃŽÂ © and the threshold capacitance C value is 100nf are chosen. The timer input is the output of the comparator where the two values of the voltage are compared to make the output of the timer based on these two values. The two voltages are one is 5V and the other is the feedback from the MOSFETs source. 2.6.2. (LM393) Comparator The comparator is used to compare the voltage between the source voltage and the feedback from the MOSFET. This is important to control the current by triggering the timer to limit the current as it is mentioned before. LM393 has several advantages for timer input which are Higher accuracy in comparators. High voltage range (2.0V to 36V) Biasing with lower input current. Lower input offset current  ±5 nA Figure 2.12 LM393 connections to the circuit In order to establish the reference voltage variable resistance is required in the voltage dividers law. The operation of the comparator is simply as follows If IN+ > IN- the comparator output = V8. If IN+ From the previous operation it can be seen that the comparator send the signal to trigger the input of the timer and the timer acts upon the applied signal therefore the MOSFET switches on and off with regard to the timer output. However, the output of the timer switches on the MOSFET when the current is high which will be disastrous to the motor. To avoid this not to happen, a design of logic gates are incorporated in the current limiting topology of the SRM. 2.6. 3. Logic gate design (SN74LS00N) Logic gate is designed according to the output of the timer which gives the positive pulses when the current exceeds to 8A and no pulse when the current is less than 8A. With the purpose of switch (totem pole) the gate of the MOSFET turns on and off at required instants of time using an external Drive Signal. Figure 2.13 shows the technique of the combination between the Drive Signal and the timer output to control the MOSFET. SN74LS00N has four NAND gates that can be used to reduce the number of ICs in PCB connection. The logic gate is connected to the timer output which will be inverted with a common emitter configuration to switch on the MOSFET when the timer output is low (Itimer Figure 2.13: (a) SN74LS00N chip (b) logic circuit connection (c) NAND gate logic signal. The MOSFET behaviour that is need according to the timer output is shown in table 1. To do that the NOT gate, OR gate and AND gate are needed before the pre totem pole connections (common ammeter topology). Current condition Timer(A) Drive Signal(B) Output of the logic gate (C) MOSFET gate signal (Output after totem pole) I > 8A MOSFET must be off 1 0 1 0 1 1 1 0 I MOSFET can be on 0 0 1 0 0 1 0 1 Table 2.1 digital signal behaviour Boolean algebra From the logic gate output we can get the function: (1) This function can be simplified (2) Figure 2.14 (a) logic gate from equation 2 (b) table shows the equavelant NAND gates [7](c) the final simblified gates using the table (b) 2.7 Curant limiting circuit simulation Curent limiting circuit ,figure 2.15 , is the simulation circuit and the combination of each part that discussed previously. Figure 2.15: current limiting circuit

Critique of the Novel Our Town Essay -- Thornton Wilder

Thornton Wilder was born on April 17, 1897, and died on December 7, 1975. He was born in Madison, Wisconsin to Amos Wilder, an American diplomat, and Isabella Wilder. Thornton Wilder started writing plays in The Thacher School in Ojai, California, and graduated from Berkeley High School in 1915. He served in the Coast Guard in World War II. After the war he attended Oberlin College, then Yale University where he earned his B.A. in 1920. His writing was honed at Yale where he was a part of the Alpha Delta Phi Fraternity which is a literary society. In 1926, he earned his M.A. in French from Princeton University. Wilder won Pulitzer Prizes for The Bridge of San Luis Rey in 1928, Our Town in 1938, and The Skin of Our Teeth in 1942. He also won the Peace Prize of the German Book Trade in 1957, the Presidential Medal of Freedom in 1963, and the National Book Award in 1967 for his novel The Eighth Day. Form, Structure, and Plot The novel is organized into three acts, each one representing a different period of time. There are only two flashbacks in the book. The first takes place in act two, after George and Mr. Webb have a conversation. They both leave the stage and the Stage Manager introduces the flashback of when Emily and George had their first date at Mr. Morgan’s drugstore. The second flashback is not so much a flashback as it is time travel. It occurs in act three after Emily Webb joins the rest of the dead. She, as well as the Stage Manager, goes back in time to revisit her twelfth birthday. The first act is of George Gibbs and Emily Webb as teens, the second act is of their marriage, and the third act is of Emily Webb’s funeral. In the play a total of twelve years is covered. Throughout the play, the tone becomes more and m... ...out that Emily is dead. Additional Comments I was not thrilled with this book, but I did not hate it. The book’s strengths are that it has good, applicable themes that are easy to understand. Another strength that the book has is that it is not written in formal diction, so it is easy to read and understand. One of its weaknesses is that it is sometimes hard to follow the plot because of the lack of narration. The reader can get confused because of sudden scene or time changes. The book does leave one lingering question: What happens to George Gibbs? Although this is not my favorite book, it will have lasting effects on me. The transience of human life is a universal theme that can be observed by anyone. Bibliography Thornton (Niven) Wilder (1897-1975). . Our Town. Wikipedia. .

Factors affecting course preference

Parent involvement is somewhat of a mystery within the field of education. Teachers often wonder how to encourage more parents to attend workshops while parents question how to best support their children's learning at home. Researchers struggle to conduct accurate studies isolating home-school collaboration as a channel for student achievement and policymakers have difficulty drafting a document that guides schools to work with â€Å"hard-to-reach† parents. Simply stated, schools and districts across the country struggle to involve parents as partners in heir children's education (Sheldon &Hutchins, 2011). Garland 2009) found that the most significant influence on the career choice of Indian students was the father. Likewise, parent's perceptions of their children's interests and abilities and their specific expectations for their child's success can affect choices, beliefs, and career actions. Similarly, because college students typically seek approval and family support reg arding specific career decisions, these students will probably experience a struggle if their career decision does not align with family expectations.In a recent duty confirmed the great influence of parents relating to career choice. It has also been established that several societies across the globe emphasize collective identity and significance of family. (Bryant et al. 2009) One of the challenges facing the accounting profession has always been how to attract competent applicants. In recent years the demand for accounting graduates has been strong. Although a severe economic downturn beginning in the fall of 2008 lessened the demand for accounting graduates, the employment outlook for entry-level accountants overall is positive.The purpose of this survey study is to assess the relative importance of factors affecting students' employment choices (Bloom & Miring, 2011). The results of this study can be useful to among others, employers, students, faculty and career counselors. R ecruiters could benefit from an understanding of factors students consider important when choosing among various employment offers. Greater understanding of influential decision factors can help the recruitment process, improve employee selection, and better match students with suitable employers.This could result in positive outcomes such as a more efficient acquirement strategy, greater employee satisfaction, and lower employee turnover. Accounting faculty and career advisors could also benefit from understanding factors affecting employment choices since they also help students assess employment opportunities. Today's graduating accounting students are members of Generation Y (Gene Years), a term used to describe those who were born between 1979 and 1994. Gene Years currently range in age from 14 and 29.Gene Years are shaped by their shared experiences due to economic, political, social, and cultural 32 Journal of Higher Education Theory and Practice volt. 1(2) 2011. Peer influen ce As we grow older, your peers actually helped shape your personality towards your strengths. You will be faced with some challenging decisions. In an article by Attar Manor she said that making decisions on your own is hard enough, but when other people get involved and try to pressure you one way or another it can be even harder.Be it school, college or workplace – making friends is important, and so is socializing, but there are ways to forge new ties and mix up with people without being pressurized by the peers. Friends never make you lose your identity, making rinds is about appreciating the differences and respecting individual tastes and still being together. Be comfortable with identity of who you are, and you will soon make new friends and be accepted by everyone. The effects of peer pressure can be prevented by simply teaching your child to be confident and comfortable in their own skin, without giving in such social influences.When making a decision it is not ther e is nothing involved for one to draw to their decision, one may not realize that this is process and that it is done every day several times a day. According to the text the definition of decision making is the process of choosing a course of action to deal with a problem or opportunity' (Shoehorning, Hunt, Osborn. & Uh-Been, 2010). Farmer (2010) also affirms that peers are not inherently positive or negative; they can be both good and bad.He further said that, peer friendships, group interactions, and influences are a part of positive development. Young people learn to evaluate themselves through the eyes of their peers, they get feedback on their personal characteristics, they gain social skills and confidence and they learn how to defer personal fulfillment to group goals. Young people also learn how to make themselves more attractive and interesting to others, they learn to control their aggressive reactions in the interest of fitting with others.Personal decision After a decis ion is made, people experience a variety of reactions. In addition, present decisions influence future decision making. Several of the outcomes that may result from a decision are regret or satisfaction; both of which influence upcoming decisions. Regret, feelings of disappointment or dissatisfaction with a choice made is one potential outcome of decision making. Interestingly, regret may shape the decision asking process. According to Abraham and Sheerer (2010), anticipated regret is the belief that the decision will be result of inaction.Anticipated regret may prompt behavior; that is, when a person indicates they will do something, such as exercise, they may follow through with their intended decision, to avoid regret. Once the decision is made, the impact of the decision, if regret is experienced, will impact future decisions. People can often get consumed with examining the other options that were available; the path not taken (Saga & Friedman, 2009). Satisfaction refers to owe pleased the decision maker is with the outcome of the decision. There are many things that impact levels of satisfaction.Boots and lounger (2011) observed individuals prefer to make their own decisions and believe they will be more satisfied with their choices; however, when people are given only undesirable options, decision makers are less satisfied than those who have had the choice made for them. Future decision making is based on past decisions, as well as levels of satisfaction or regret. Even though there is evidence to support this notion, in many cases, particularly when the session may be reversed, decisions may be based on the reversibility factor (Gilbert, & Bert, 2010).Significant to individuals' satisfaction is that people are willing to pay a premium for the opportunity to change their minds at a later date. Decision making is a critical aspect to feeling successful and happy in life; decision making is at the root of all we do. It is important to develop effective d ecision making skills and strategies. Problem solving strategies include, but are not limited to brain storming, cost benefit analysis, written remediation plans, and an examination of possible choices. The decision making process can be complicated and overwhelming.As a result, it is valuable for individuals to learn a model to follow, that may be applied to everyday decisions, as well as life changing choices (Western, Christianson, Food, & Santiago-Riviera, 2009). Justification of the study Parents are taking vital part in making decision in the lives of their children. It always been subjective that parents know what is best for their children and they want them to be in the right track. Children look for advice and approval for what is right and good for them in terms of decision making because sometimes they are fitful of what career preferences to choose if they will succeed or regret.Peer influence helps us to have decisions in life especially in the mode of work. It gives u s self-assurance and at ease on the career decision we made. Collaboration with our friends and mingle with others increase and shape our personal growth to set goals for achievement in ourselves. Personal decision makes us to become independent in our life. Deciding of what you really want makes you learn from previous occurrence and to become stronger to face challenges that you will become successful in the end.

Ethical Judgement Methods - 1195 Words

Ethics are a standard of right behaviour controlled by our moral principles. Our ethics control our actions, what we believe in and say is somewhat affected by our ethics. Although our ethics play an imperative role in our lives it sometimes may be limitation, especially when it comes to knowledge our ethics may become an obstacle. Some say ethics there to protect us, some argue they are a hindrance. Our ethics come from two major ways of knowing which are emotion and reasoning. This essay will tackle the knowledge issue which is â€Å"Is our ethical judgements hindrance on our knowledge a good thing?† I will be focusing on two areas of knowing which Natural Sciences and the Arts. To some ethics can simplify life, by just following what their religion or what their culture say. For example ‘you shall not kill’; this is a worldwide ethical view. It is seen in many religions and culture this gives a sense of order. On the other hand when someone is being raped and their only source of defence is to kill the person who is raping her or him. Would this still be unethical? On the other hand ethics can also not give straightforward answers, because everyone is different, because our ethics come from our culture, environment and the societies we surround ourselves with. Some say the source of our ethics is empiricism. This can sometimes lead moral principles clashes. So whose ethics values are right? Even when it comes to individuals their ethics are never consistent. Most peopleShow MoreRelatedEthical Judgements Limit the Methods Available1400 Words   |  6 PagesMeanwhile the arts is a discipline in which we express both ethical and unethical ideas that are more subjective. Both areas of knowledge are affected by the ethical judgements that people make in the production and of knowledge. Ethical judgements are related to human moral values and they affect how people should or should not act (Dombrowski, 2007). Even though some may say that ethical judgments vary by subject, location and time, but all ethical judgments have to be by conscious choices. ThereforeRead MoreEthical Judgments in the Arts and Natural Sciences1390 Words   |  6 Pages Ethical judgements are a very potent limiting factor in both the arts and natural sciences, and although these judgements are often times subjective to specific people or cultures, they are extremely beneficial. The exploration of these ethical judgements is vitally important in order to understand why exactly they are thought to limit the methods available in the production of knowledge in these areas, but must also be looked at with a fair and balanced perspective. To begin with, the definitionRead MoreJudgement On Clean Air Or Money1343 Words   |  6 PagesJudgement on Clean Air or Money Economic development will damage the environment more or less, so the choice between the economic development and environmental protection has always been a difficult social problem that challenges many developing countries. China has been suffering by its air pollution for years because people burn too much fossil fuels with few regulations before it become a serious social problem for the whole country. United States as the top of developed countries is also notRead MoreEthics, Art, and Natural Science1353 Words   |  5 Pagesthe question- to what extent, do ethical beliefs limit our ability to effectively study the arts and natural sciences? To understand how ethics affects both natural science and the arts, it is important to have an understanding on the topic of ethics. Ethics as defined by Aristotle reaches down into the unfathomable world of the human psyche. The first step to understanding ethics begins with understanding that ethics stems from moral judgements. A moral judgement is simply a determination of whatRead MoreThe Ethical Decision Making Of Bilingual People Essay1510 Words   |  7 Pagesresult of that many people speak both Chinese and English. This research paper discusses the ethical decision making of bilingual people to challenge the most common theory that ethical decisions does not differ regardless of what language the subject is making it in. Given the rapid globalization many accounting students and professionals speak multiple languages and this profession require people to make ethical judgments in complex situations. And there has been very limited prior research in thisRead MoreQuestions O n Personal Morals And Ethics956 Words   |  4 Pagesindividual (Ianinska Garcia-Zamor, 2006). The common thread is right from wrong and following those standards when making decisions and dealing with people. According to Guffey and Loewy (2015), there are a set of question to ask when trying to make an ethical decisions. Some of these same questions can be applied to moral decision making as well. For example, how would one feel if family, friends, or coworkers found out about the decision to do whatever it takes to keep a job, even if it were unethicalRead MoreEmotivism1571 Words   |  7 PagesEMOTIVISM LOGICAL POSITIVISM Logical positivism embraced a scientific method for verifying knowledge – a process of verification – which excluded the possibility of moral facts. This shows the influence of David Hume (1711-1776), who believed that sentiment was the source of right and wrong. If you decide to help someone in need, you do so because you have feelings, not because you have reason. Hume believed in a common feeling for each other’s welfare. We all have a capacity for compassion, butRead MoreDoes Proof Can Be Better Than Others? Essay1210 Words   |  5 Pagesexperiences and how they might be coloring my judgement. I believe these are important aspects to consider when making a reasoned judgment. First, you must look at each and distinguish arguments on both sides of your argument. Then you identify and consider the relative strength to each. When you consider these aspects, you are able to first identify both sides of the argument and choose strong evidence that will take you closer to forming your own reasoned judgement. I believe this is important as it givesRead MoreEthical Judgement Can Restrain Someone from Expanding Their Knowledge1160 Words   |  5 Pageschild, I obeyed the rules, for the most part. But now, as a young adult, I realize that my parents ethical judgement towards profane music, impacted my understanding of the true purpose of hip hop music and the goal of the artists. I came to the realization that ethical judgement can truly restrain someone from expanding their knowledge. I then began to wonder to what extent can the ethical judgement towards the mechanisms utilized in the arts, and other areas of knowledge like the natural scienceRead MoreEthics And Management : Ethical Considerations By Observers Of Earnings Management909 Words   |  4 PagesAbstract. The article reviewed was Ethically Related Judgments by Observers of Earnings Management. The abstract emphasizes that the earning management is the major ethical issues in acco unting. Regulators and investors examine professional judgment through legal books (p. 285). Introduction. The author studies accounting methods, earnings management, and financial reporting to examine the ethicalness of judgments. Management’s ethics play a key role in earnings management activities and financial