An Adaptive Proportional Resonant Controller forSingle Phase PV Grid Connected Inverter Based onBand-Pass Filter Technique

ABSTRACT:  

This paper being an adaptive proportional resonant (PR) controller for single phase grid connected inverter that adapts its control parameters to grid impedance change. Forth order band bass filter is method and then merge with the adaptive system for on-line detection of any variations in the resonance frequency. The estimated frequency is then prepared by statistical signal processing operation to identify the variations in the grid impedance. For the on–line tuning of the PR parameters, a look-up table technique is utilized and its parameters are linked with the measure impedance values. Simulation results based on MATLAB environment clearly verify the effectiveness of the proposed control scheme for 2 kW grid connected inverter system.

 

KEYWORDS:
  1. Adaptive Proportional Resonant Controller
  2. Grid Impedance Estimation
  3. LCL Filter
  4. Look-up Table

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1. Block diagram of the proposed adaptive PR controller.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation result of emulated grid voltage.

Fig.3. FFT analysis of grid current. (a) APR controller. (b).PR controller.

Fig. 4. Online adaptation of the APR control parameters.

Fig. 5. Grid voltage and current waveforms under changeable grid

impedance with the proposed control strategy.

 CONCLUSION:

 A new control strategy based on an adaptive proportional resonant (APR) controller has been grown and successfully proved on a simulated 2 kW single phase grid tide PV inverter. A fourth order Sallen-Key band pass filter tailored to the system to taking the harmonic components around the resonant frequency has been execute. data signal processing metthod was employed in order to provide the controller with signals compare to the variable grid impedance. A large low level of current total harmonic distortion (THD) is reach in comparison with conventional PR controller and submission with IEEE929-Standard has been show.

REFERENCES:

[1] S. Kouro, J. I. Leon, D. Vinnikov, and L. G. Franquelo, “Grid-Connected Photovoltaic Systems: An Overview of Recent Research and Emerging PV Converter Technology,” IEEE Industrial Electronics Magazine, vol. 9, pp. 47-61, 2015.

[2] “IEEE Recommended Practice for Utility Interface of Photovoltaic (PV) Systems,” in IEEE Std 929-2000, ed, 2000.

[3] “IEEE Draft Application Guide for IEEE Standard 1547, Interconnecting Distributed Resources With Electric Power Systems,” in IEEE Unapproved Draft Std P1547.2/D11, Sept 2008, ed, 2008, p. 1.

[4] H. M. El-Deeb, A. Elserougi, A. S. Abdel-Khalik, S. Ahmed, and A. M. Massoud, “An adaptive PR controller for inverter-based distribution generation with active damped LCL filter,” in 2013 7th IEEE GCC Conference and Exhibition (GCC), 2013, pp. 462-467.

[5] W. L. Chen and J. S. Lin, “One-Dimensional Optimization for Proportional-Resonant Controller Design Against the Change in Source Impedance and Solar Irradiation in PV Systems,” IEEE Transactions on Industrial Electronics, vol. 61, pp. 1845-1854, 2014.

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 of loss 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 optimal Ids 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(a). 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(a) Efliciency- vs- Load-Torque at 120 radis, (b) Efliciency- vs- Speed

Fig. 5(a) 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:

[1] 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.

 

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.