Fuzzy Efficiency Enhancement of Induction Motor Drive

ABSTRACT:

Efficiency improvement of motor drives is important not only from the viewpoints of energy loss and hence cost saving, but also from the perspective of environmental pollution. Several efficiency optimization methods for induction motor (IM) drives have been introduced nowadays by researchers. Distinctively, artificial intelligence (AI)-based techniques, in particular Fuzzy Logic (FL) one, have been emerged as a powerful complement to conventional methods. Design objectives that are mathematically hard to express can be incorporated into a Fuzzy Logic Controller (FLC) using simple linguistic terms. The merit of FLC relies on its ability to express the amount of ambiguity in human reasoning. When the mathematical model of a process does not exist or exists with uncertainties, FLC has proven to be one of the best alternatives to move with unknown process. Even when the process model is well-known, there may still be parameter variation issues and power electronic systems, which are known to be often approximately defined.

The purpose of this paper is to demonstrate that a great efficiency improvement of motor drive can be achieved and hence a significant amount of energy can be saved by adjusting the flux level according to the applied load of an induction motor by using an on-line fuzzy logic optimization controller based on a vector control scheme. An extensive simulation results highlight and confirm the efficiency improvement with the proposed algorithm.

KEYWORDS

1.      Induction Motor Drive

2.      Indirect Field Oriented Control (IFOC)

3.      Efficiency Enhancement

4.      Losses Minimization

5.      Optimization

6.      Fuzzy Logic

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1, Block diagram of the optimization system

EXPECTED SIMULATION RESULTS:

Fig.2, Motor Performances Comparison

Fig.3, Motor efficiency evolution with motor load

CONCLUSION:

This paper aims to improve the induction motor drive efficiency that leads to a significant amount of energy saving. This efficiency enhancement is carried out by adjusting the flux level depending on the applied load of an induction motor by using an on-line fuzzy logic optimization controller based on a vector control scheme. A series of the induction motor drive performances are obtained with a variable load under this proposed algorithm. The application of the proposed algorithm yields to a series of simulation performances of the induction motor drive with a variable load. They present the IM drive efficiency evolution with a certain load profile with the suggested losses minimization strategy based on fuzzy control and the conventional field oriented control. The comparison between these two control schemes reveals that the achieved results are of a great interest. Indeed, the fuzzy control contributes with a great deal to the efficiency improvement for all operating speeds particularly in light load region. This contribution conducts to a paramount energy saving and hence to environment protection.

REFERENCES:

[1] I. Boldea, A. Nasser, The Induction Machine Design Handbook, CRC Press Inc; 2nd Revised Edition, 2009.

[2] Jinchuan. Li and all, “A new Optimization Method on Vector Control of Induction Motors”, Electric Machines and Drives, 2005 IEEE International Conference, 15-18 May 2005, pp.1995-2001.

[3] H. Sepahv and, Sh. Ferhangi, “Enhancing Performance of a Fuzzy Efficiency Optimizer for Induction Motor Drives”, Power Electronics Specialists Conference, 2006. PESC '06. 37th IEEE, 18-22 June.2006, pp.1-5.

[4] Branko Blanusa and all, “An Improved Search Based Algorithm for Efficiency Optimization in the Induction Motor Drives”, XLII Konferencija- za ETRAN, Hercy-Novi, 2003.

[5] D. S. Kirischen, D. W. Novoty and T. A. Lipo, “Optimal Efficiency Control of an Induction Motor Drive”, IEEE Transaction on Energy Conversion, Vol. EC-2, N° 1, March 1987, pp.70-76.

Efficiency Optimization of Induction Motor Drive in Steady- State using Artificial Neural Network

ABSTRACT:

Induction motors have good efficiency at rated conditions, but at partial loads if operated with rated flux, they show poor efficiency, Motors in such conditions waste a lot of electricity, results in increased operational cost, hence significant loss of revenue, if run for long duration, Because of robustness, good power/mass relation, low cost and easy maintenance throughout its life cycle, induction motors, particularly squirrel cage induction motors are vastly used in industries. Because of the huge number of operational units worldwide, they consume a considerable amount of electrical energy, so even a minute efficiency improvement may lead to significant contributions in global electricity consumption, revenue saving and other environmental aspects. This paper uses key concepts of loss model control (LMC) and search control (SC) together for efficient operation of induction motors used in various industrial applications, where aforesaid load conditions may occur for prolonged durations. Based on the induction motor loss model in d-q frame, and using classical optimization techniques, done earlier, an optimal Ids expression in terms of machine parameters and load parameters is used to estimate optimal Ids values for various load conditions, offline, and finally tabulated. Based on which, an artificial neural network (ANN) controller is designed, taking torque and speed as input and Ids as output. The ANN controller reproduces the optimal Ids * value, as per load conditions, in feed-forward manner, and thus eliminates run-time computations and perturbations for optimal flux. The ANN training is performed in MATLAB and the results have shown the superb accuracy of the model. Dynamic and steady-state performances are compared for conventional vector control (constant Ids) and proposed optimal control (optimal Ids) operations. Excellent dynamic as well as superior efficiency performance (1-18%) at steady- state, is observed in optimal flux operation, for load torque above 60% of rated, in simulation, for a wide range of speed, by the proposed method. Also, the method is easy to implement for real - time industrial facilities, fast response, ripple free operations, and offers higher energy savings ratio as compared to useful output power, in comparison with similar works done earlier.

KEYWORDS:

1. Energy-efficiency
2. Induction motor drive
3. Vector control
4. Optimal control
5. Efficiency optimization
6. ANN

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1(a). MATLAB model for efficiency validation, (b) Id,* values at different speeds

EXPECTED SIMULATION RESULTS:

Fig. 2(a) Efficiency- vs- Load-Torque at 120 rad/s, (b) %age Power saving - vs- Speed

Fig. 3. Speed, Torque, Input power and Efficiency performance at for a load cycle of (150 N -m, 120 radls) for 4 sec, (200 N -m, 150 rad/s) for 3 sec, and (150 Nm, 90 rad/s) for 3 sec.

Fig. 4. Switching state performances at sample 120 rad/sec speed at a load cycle of 16 seconds.

CONCLUSION:

In this work, it is verified that the optimal flux operation is superior to that of vector control method under steady - state condition, in terms of efficiency enhancement and hence energy-saving. In general 1 - 18% efficiency improvement is observed on 50 HP, 60 Hz motor, at different load-torques (above 60%) and speeds, in Simulink environment. Efficiency improvement margin is seen degraded below 60% of rated load, and conventional vector control performs better. This can be seen as shortcoming of proposed method. The dynamic performance is seen satisfactory, similar to vector control or even better, in terms of overshoot, undershoot and settling time, speed and torque tracking accuracy is little bit deviated, but still the proposed approach is extremely suitable for such an application where maintaining speed and torque very precisely is not a critical issue, such as an induction motor drive used in an industrial HV AC applications [7, Bose 2004]. A lot of electricity can be saved with this minute compromise in speed and torque accuracy, since it offers higher amount of energy savings as compared to existing methods, hence a great contribution towards social and environmental aspects. The proposed method can be easily implemented on other induction motor drive systems also, for which the steady-state speed-vs.torque load characteristics are already known or can be predicted. The offline optimization as done here, is a limitation, as the optimal flux trajectories are only valid for one specific application, can also be considered as drawback. But, the proposed hybrid approach eliminates the need of run-time computation complexity in traditional loss model controller (LMC), so less hardware installations required in implementation, hence cost-effective. Also, since no run-time perturbations happening as it usually happen in conventional search control (SC), so no torque ripples, hence less wear and tear of induction motor drive.

REFERENCES:

[1] A. H. M. Yatim and W. M. Utomo, "To develop an efficient variable speed compressor motor system," Universiti Teknologi Malaysia (UTM), Skudai, Malaysia, 2007.

[2] R. Hanitsch, "Energy efficient electric motors," University of Technology, Berlin, Germany, 2000. 

[3] Y. Yakhelef, "Energy efficiency optimization of induction motors," Boumerdes University, Boumerdes, Algeria, 2007.

[4] M. W. Turner, V. E. McCormick and J. G. Cleland, Efficiency optimization control of AC induction motors: Initial laboratory results, United States Environmental Protection Agency, Research and Development, National Risk Management Research Laboratory, 1996.

[5] T. Fletier, W. Eichhammer and 1. Schleich, "Energy efficiency in electric motor systems: Technical potentials and policy approaches for developing countries," United Nations Industrial Development, Vienna, 2011.

Efficiency Optimization of Induction Motor Drive at Steady-State Condition

ABSTRACT: 

Induction motors are workhorse of industries due to its power/mass relation, efficiency, low cost and nearly maintenance free operation in its life cycle. However motors with low efficiency waste a lot of energy that will increase its operational cost. As a result of high energy consumption and the huge number of operating units, even a small increase in efficiency improvement has significant effect on the entire energy consumptions and operational cost. This paper uses key features ofloss model control (LMC) and search control (SC) together for estimation and reproduction of optimal flux component of current (Ids), for optimal efficiency operation of induction motor. At first, a d-q loss model of induction motor is used to derive a loss-minimization expression considering core saturation. The loss expression is used to derive optimalIds expression and then Ids is estimated for various load profiles and finally tabulated. Based on those tabulated values, a look-up table in MATLAB is designed, and thus optimal Ids* value can be reproduced, depending upon run-time load profile, in feed-forward manner, and thus eliminates run-time loss model complex computation. Efficiency is compared for conventional vector control (constant Ids) and proposed optimal control (optimal Ids) operations. Superior efficiency performance (1-18%) is observed in optimal flux operation at steady-state, for load torque above 60% in simulation, for wide range of speed. The proposed hybrid concept is easy to implement, run-time computation free operation, ripple free operation, and offers higher power saving ratio with respect to useful output power.

KEYWORDS:
1. Induction motor drive
2. Efficiency optimization
3. Vector control
4. Optimal control
5. Look-up table

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1. MATLAB model for efficiency validation

EXPECTED SIMULATION RESULTS:

Fig. 2. Speed, Torque and Efficiency perfonnance at (a) at rated load torque (200N-m) at 120 radis speed, 12% efficiency rise, (b) at 3/4th rated load torque (150Nm) at 120 radis speed, 5% efficiency rise

Fig 3. Ids* values at different speeds

Fig. 4  Efficiency- vs- Load-Torque at 120 radis, (b) Efliciency- vs- Speed

Fig. 5 Input Power- vs- Speed, (b) %age power saving- vs- speed

CONCLUSION:

In this work, it is verified that the optimal flux operation is superior to that of vector control method under steady - state condition, in terms of efficiency enhancement and hence energy-saving. In general I - 18% improvement is observed on 50 HP, 60 Hz motor, at different load-torques (above 60%) and speeds, in simulink environment. Efficiency improvement margin is seen degraded below 60% of rated load, and conventional vector control performs better. This can be seen as shortcoming of proposed method. The dynamic performance is seen satisfactory (similar to vector control), but speed and torque tracking accuracy is degraded a bit, but still the proposed approach is extremely suitable for such an application where maintaining speed and torque very precisely is not a critical issue, such as an induction motor drive used in an industrial HV AC applications. A lot of electricity can be saved with this minute compromise in speed and torque, since it offers higher amount of energy savings as compared to existing methods, hence a great contribution towards social and environmental aspects. The proposed method can be easily implemented on other induction motor drive systems also, for which the steady-state speed-vs.-torque load characteristics are already known or can be predicted. Also, the proposed hybrid approach eliminates the need of runtime computation complexity in traditional loss model controller (LMC), so less hardware installations required in implementation, hence cost-effective. Also, since no runtime perturbations happening as it usually happen in conventional search control (SC), so no torque ripples, hence less wear and tear of induction motor drive.

 REFERENCES:

[I] A. H. M. Yatim and W. M. Utomo, "To develop an efficient variable speed compressor motor system," universiti teknologi Malaysia (UTM), Skudai, Malasia, 2007.

[2] R. Hanitsch, "Energy efficienct electric motors," university of technology berlin, germany, 2000.

[3] Y. Yakhelet: "Energy efficiency optimization of induction motors," Boumerdes University, Boumerdes, Algeria, 2007.

[4] M. W. Turner, V. E. McCormick and 1. G. Cleland, Efficiency optimization control of AC induction motors: Initial laboratory results, United States Environmental Protection Agency, Research and Development, National Risk Management Research Laboratory, 1996.

[5] T. Fletier, W. Eichhammer and 1. Schleich, "Energy efficiency in electric motor systems: Technical potentials and policy approacehs fir developing countries," United Nations Industrila Development, Vienna,2011.

Design and Simulation of Single Phase Shunt Active Power Filter using MATLAB

ABSTRACT: 

Power Quality issues are becoming a major concern of today’s power system engineers. Harmonics play significant roll in deteriorating power quality, called harmonic distortion. Harmonic distortion in electric distribution system is increasingly growing due to the widespread use of nonlinear loads. Large considerations of these loads have the potential to raise harmonic voltage and currents in an electrical distribution system to unacceptable high levels that can adversely affect the system. IEEE standards have defined limits for harmonic voltages and harmonic currents. Active power filters have been considered a potential candidate to bring these harmonic distortions within the IEEE limits. This paper deals with an active power filter (APF) based on simple control. A voltage source inverter with pulse width modulation (PWM) is employed to form the APF. A diode rectifier feeding capacitive-resistive load is considered as nonlinear load on ac mains for the elimination of harmonics by the proposed APF. MATLAB model of the scheme is simulated and obtained results are studied.

KEYWORDS:
1. Power Quality
2. THD
3. Non-linear Load
4. PWM

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1 Principle of Shunt connected SPAPF

CIRCUIT DIAGRAM:

Figure 2. Basic Circuit of Single Phase APF 

EXPECTED SIMULATION RESULTS:

Figure 3. Load Current without SPAPF

Figure 4. Load Current Harmonic Spectrum without SPAPF

Figure 5. Load Voltage without SPAPF

Figure 6. Load Current Harmonic Spectrum without SPAPF

           

Figure 7. Load Current with SPAPF

Figure 8. Load Current Harmonic Spectrum with SPAPF

Figure 9. Load Voltage without SPAPF

Figure 10. Load Voltage Harmonic Spectrum with SPAPF

CONCLUSION:

A simple control scheme of the single phase active power filter is proposed which requires sensing of one current and two voltages only. The APF results in sinusoidal unity power factor supply current. It is concluded that the reduced value of dc bus capacitor is able to give quite satisfactory operation of the APF system. The voltage controller gives fast response. The proposed APF is able to reduce THD of supply current and supply voltage below prescribed permitted limits specified by IEEE 519.

REFERENCES:

[1] D. C. Bhonsle, Dr. R. B. Kelkar and N. K. Zaveri, “Power Quality Issues-In Distribution System”, IE(I) 23rd National Convention of Electrical Engineers, Pune, November 2007 Proceedings, pp. 108-111.

[2] K. C. Umeh, A. Mohamed, R. Mohmed, “ Comparing The Harmonic Characteristics of Typical Single Phase Nonlinear Loads”, National Power Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 383-387.

[3] Mohamed S. A. Dahidah, N. Mariun, S. Mahmod and N. Khan, “Single Phase Active Power Filter for Harmonic Mitigation in Distribution Power Lines”, National Power and Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 359-362.

[4] Dalila Mat Said Ahmed, Abdullah asuhaimi, Mohd Zin, "Power Supply Quality Improvement: Harmonic Measurement and Simulation," National Power and Energy Conference (PECon), 2003 Proceedings, Bangi, Malaysia, pp. 352-358.

[5] C. Gopalkrishnan, K Udaykumar, T. A. Raghvendiran, "Survey of Harmonic Distortion for Power Quality Measurement and Application of Standard including Simulation," 2001, Anna University, India.

Application of Unified Power Flow Controller in Interconnected Power Systems—Modeling, Interface, Control Strategy, and Case Study

ABSTRACT:

In this paper, a new power frequency model for unified power flow controller (UPFC) is suggested with its dc link capacitor dynamics included. Four principal control strategies for UPFC series element main control and their impacts on system stability are discussed. The main control of UPFC series element can be realized as a combination of the four control functions. The supplementary control of UPFC is added for damping power oscillation. The integrated UPFC model has then been incorporated into the conventional transient and small signal stability programs with a novel UPFC-network interface. Computer tests on a 4-generator interconnected power system show that the suggested UPFC power frequency model and the UPFC- network interface method work very well. The results also show that the suggested UPFC control strategy can realize power flow control fairly well and improve system dynamic performance significantly.

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 

Fig. 1. Transmission line with UPFC installed.

CONTROL SYSTEM:

Fig. 2. The main control and phasor diagram.

EXPECTED SIMULATION RESULTS:

Fig. 3. Plots of case 1a.

Fig. 4. Plots of case 1b.

Fig. 5. Plots of case 1c.

Fig. 6. Effects of supplementary control.

Fig. 7. Results of the suggested control scheme.

CONCLUSION:

The suggested UPFC power frequency model and the developed UPFC-network interface method work very well in the study of power system dynamics with satisfied convergence and accuracy. Four principal main control strategies are discussed and the computer tests results support the discussion conclusion very well. The constant power flow control is good for steady state control and the constant series compensation control is useful for first swing stability. The supplementary control is very efficient in damping intcrarea power oscillation. The suggested UPFC control can realize the desired control strategy flexibly and improve system dynamic performance significantly.

REFERENCES:

[1] L. Gyugyi, “Unified Power-Flow Control Concept for Flexible AC Transmission Systems,” IEE Proceedings-C, vol. 139, no. 4, pp. 323–331, July 1992.

[2] I. Papic, P. Zunko, and D. Povh, “Basic Control of Unified Power Flow Controller,” IEEE Trans. on Power Systems, vol. 12, no. 4, pp. 1734–1739, Nov. 1997.

[3] R. Mihalic, P. Zunko, and D. Povh, “Improvement of Transient Stability Using Unified Power Flow Controller,” IEEE Trans. on Power Delivery, vol. 11, no. 1, pp. 485–491, Jan. 1996.

[4] K. S. Smith, L. Ran, and J. Penman, “Dynamic Modeling of a Unifed Power Flow Controller,” IEE Proc.-Gener. Transm. Distrib., vol. 144, no. 1, pp. 7–12, Jan. 1997.

[5] M. Noroozian, L. Angquist, and M. Ghandhari, et al., “Improving Power System Dynamics by Series-connected FACTS devices,” IEEE Trans. on Power Delivery, vol. 12, no. 4, pp. 1635–1641, Oct. 1997.

High-Gain Single-Stage Boosting Inverter for Photovoltaic Applications

High-Gain Single-Stage Boosting Inverter

for Photovoltaic Applications

ABSTRACT

This paper introduces a high-gain single-stage boosting inverter (SSBI) for alternative energy generation. As compared to the traditional two-stage approach, the SSBI has a simpler topology and a lower component count. One cycle control was employed to generate ac voltage output. This paper presents theoretical analysis, simulation and experimental results obtained from a 200 W prototype. The experimental results reveal that the proposed SSBI can achieve high dc input voltage boosting, good dc–ac power decoupling, good quality of ac output waveform, and good conversion efficiency.

KEYWORDS

1.      Microinverter

2.      one cycle control (OCC)

3.      tapped inductor (TI)

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig.1. Topology of the proposed SSBI.

EXPECTED SIMULATION RESULTS

                       

Fig. 2. Simulated waveforms of the proposed SSBI on the line frequency

scale.

          

Fig. 3. Simulated waveforms of the SSBI’s output voltage Vac , dc-link voltage

Vdc , and dc input source current Ig with the TI operating at the CCM–DCM

boundary (Po = Pob ).

                

Fig. 4. Simulated waveforms of the SSBI’s output voltage Vac , dc-link voltage

Vdc , and dc input source current Ig : (a) illustrating the undistorted output

voltage Vac , when SSBI is operated in deep DCM just above the minimum

power level Po > Pomin and (b) illustrating the peak-shaving distortion of the

output voltage Vac for Po < Pomin .

CONCLUSION

A high-gain SSBI for alternative energy generation applications is presented in this paper. The proposed topology employs a TI to attain high-input voltage stepup and, consequently, allows   operation from low dc input voltage. This paper presented principles of operation, theoretical analysis of continuous and discontinuous modes including gain and voltage and current stresses. To facilitate this report, two stand-alone prototypes one for 48 V input and another for 35 V input were built and experimentally tested. Theoretical findings stand in good agreement with simulation and experimental results. Acceptable efficiency was attained with low-voltage input source. The proposed SSBI topology has the advantage of high voltage stepup which can be further increased adjusting the TI turns ratio. The SSBI allows decoupled control functions. By adjusting the boost duty cycle Dbst, the SSBI can control the dc-link voltage, whereas the output waveform can be shaped by varying the buck duty cycleDbk. The ac–dc power decoupling is attained on the high-voltage dc link and therefore requires a relatively low capacitance value. The OCC control method was applied to shape the output voltage. OCC’s fast response and low sensitivity to dc-bus voltage ripple allowed applying yet smaller decoupling capacitor value, and has demonstrated low THD output for different types of highly nonlinear loads.

REFERENCES

[1] S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “A review of singlephase grid-connected inverters for photovoltaic modules,” IEEE Trans. Ind. Appl., vol. 41, no. 5, pp. 1292–1306, Sep. 2005.

[2] D. C. Martins and R. Demonti, “Interconnection of a photovoltaic panels array to a single-phase utility line from a static conversion system,” in Proc. IEEE Power Electron. Spec. Conf., 2000, pp. 1207–1211.

[3] Q. Li and P.Wolfs, “A current fed two-inductor boost converter with an integrated magnetic structure and passive lossless snubbers for photovoltaic module integrated converter applications,” IEEE Trans. Power Electron., vol. 22, no. 1, pp. 309–321, Jan. 2007.

[4] S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “Power inverter topologies for photovoltaic modules—A review,” in Proc. Ind. Appl. Conf., 2002, vol. 2, pp. 782–788.

[5] C. Vartak, A. Abramovitz, and K. M. Smedley, “Analysis and design of energy regenerative snubber for transformer isolated converters,” IEEE Trans. Power Electron., vol. 29, no. 11, pp. 6030–6040, Nov. 2014.