Reduced-Order Feedback Linearization for Independent Torque Control of a Dual Parallel-PMSM System

 ABSTRACT:

Connecting two PMSMs in parallel to a 2-level 3-leg inverter gives a way to build up a high power-density driving system using existing electronic devices. But this type of system has a nature of nonlinearity that creates an obstacle in high performance control and the original system cannot be feedback-linearized directly. This article presents a reduced-order feedback-linearization method. In the first place, an extra order-reducing step that separates the system as a main system and an auxiliary system is applied. Then a feedback-linearization method is applied to the reduced-order system. With these effort, the original system can be converted into a linear time-invariant system bringing the controller design problem into the linear domain. In the last step, a linear robust state-feedback controller is used to achieve the speed control as well as compensate the unmeasurable external load torque. An extensive experiment is given to verify the feasibility and good performance in a highly unbalanced load torque situation of the designed controller.

KEYWORDS:

1.      Parallel PMSM

2.       Robust control

3.       Feedback-linearization

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1. Proposed Controller Scheme.

EXPECTED SIMULATION RESULTS:

 

Figure 2. Speed And _D Response Of Speed Command Experiment.

 

Figure 3. Current Response Of Speed Command Experiment.

 

Figure 4. Speed And _D Response Of _D Command Experiment.

Figure 5. Current Response Of _D Command Experiment.

 CONCLUSION:

In this article, we have presented a two-step state-feedback controller for the MIDPMSM system such that the two machines are carried out in closed-loop systems for handling the highly unbalanced load torque situation. This article proposes a new way to linearize a nonlinear system if feedback-linearization cannot be applied directly. The major contribution can be summarized in three aspects. First of all, a state-space description for the MIDPMSM system is set up, and it is an affine nonlinear system with unknown inputs. And then, the original affine nonlinear system is linearized through two steps: order reducing and state-feedback linearization. With these two steps, the controller design problem is brought into the LTI system domain. Secondly, in the state-feedback linearization stage, the stability of the constrained two-dimensional subsystem (7) is fully considered and dealt with. Indeed, in order to keep its stability, the calculation of the disturbance compensation gain k is given by analyzing eigenvalue constraints through solving its characteristic polynomial. Thirdly, based on the reduced-order linearized system, a state feedback controller together with an integrator is designed. In this way, both goals, closed-loop stability and reference tracking, are reached. The experiment also proves that an open-loop machine can have the risk of becoming unstable when the "master-slave" method is used. The proposed controller can avoid this situation by putting both machines under closed-loop control. Although the proposed controller design method has shown its great advantages, at least one drawback of the controller is also left. This controller can hardly handle the singularity point of the system, which creates an obstacle. How to overcome the drawback becomes one of our next considerations.

 REFERENCES:

 [1] Z. Deng and X. Nian, ``Robust control of two parallel-connected permanent magnet synchronous motors fed by a single inverter,'' IET Power Electron., vol. 9, no. 15, pp. 2833_2845, Dec. 2016.

[2] J. M. Lazi, Z. Ibrahim, M. H. N. Talib, and R. Mustafa, ``Dual motor drives for PMSM using average phase current technique,'' in Proc. IEEE Int. Conf. Power Energy, Kuala Lumpur, Malaysia, Nov. 2010, pp. 786_790.

[3] A. A. A. Samat, D. Ishak, P. Saedin, and S. Iqbal, ``Speed-sensorless control of parallel-connected PMSM fed by a single inverter using MRAS,'' in Proc. IEEE Int. Power Eng. Optim. Conf., Melaka, Malaysia, Jun. 2012, pp. 35_39.

[4] A. Del Pizzo, D. Iannuzzi, and I. Spina, ``High performance control technique for unbalanced operations of single-vsi dual-PM brushles motor drives,'' in Proc. IEEE Int. Symp. Ind. Electron., Bari, Italy, Jul. 2010, pp. 1302_1307.

[5] J. M. Lazi, Z. Ibrahim, M. Sulaiman, I. W. Jamaludin, and M. Y. Lada, ``Performance comparison of SVPWM and hysteresis current control for dual motor drives,'' in Proc. IEEE Appl. Power Electron. Colloq. (IAPEC), Johor Bahru, Malaysia, Apr. 2011, pp. 75_80.

Peak Current Detection Starting based Position Sensorless Control of BLDC Motor Drive for PV Array Fed Irrigation Pump

ABSTRACT:

a single stage position sensorless control based solar power fed PMBLDC (Permanent Magnet Brushless DC) motor drive scheme for irrigation pump is proposed in this paper. The proposed system is designed without using any mechanical sensor to reduce the cost along with the complexity of the system with optimum utilization of the solar Photovoltaic (PV) power. The proposed system integrated with a PMBLDC motor drive coupled to a water pump is controlled by an inverter input voltage sensing based position sensorless control with high current detection and commutation point estimation based starting to wide speed range control .Elimination of position sensor, makes the system control compact and cheaper. The peak current estimation based starting in sensorless mode, enables soft starting restricting high starting current with reliability like sensor based operation. The proposed drive is tested and validated on a developed laboratory prototype and its suitability is justified with different test results under steady state and dynamic operating conditions.

KEYWORDS:

1.      Peak Current detection based starting

2.       Position sensorless control

3.      Incremental Conductance MPPT Algorithm

4.      PMBLDC motor drive

5.      Water pumping

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1 System configuration of position sensorless brushless DC motor drive operated aqua pumping

EXPECTED SIMULATION RESULT:

 

Fig.2 Solar PV Array Performance (a) Steady-state and Starting performance at 1000 W/m2 insolation (b) Dynamic performance varying from 500 W/m2 to 1000 W/m2

 

Fig. 3 BLDC motor performance at sensorless scheme(a)Zero starting and steady state performance at 1000W/m2 irradiance(b)Dynamic performance varying from 500 W/m2 to 1000 W/m2 irradiance

 

CONCLUSION:

Position sensorless control scheme of the BLDC motor has been presented for irrigation pump application. Sensorless control scheme has been justified for adverse environment application especially for rural areas. The performance of the proposed configuration has been evaluated satisfactory for water pumping application at different weather conditions.

REFERENCES:

[1] S. Jain, A. K. Thopukara, R. Karampuri and V. T. Somasekhar, “A Single-Stage Photovoltaic System for a Dual-Inverter-Fed Open-End Winding Induction Motor Drive for Pumping Applications, ” in IEEE Transactions on Power Electronics, vol. 30, no. 9, pp. 4809-4818, Sept. 2015

[2] L. An and D. D. Lu, “ Design of a Single-Switch DC/DC Converter for a PV-Battery-Powered Pump System With PFM+PWM Control, ” in IEEE Transactions on Industrial Electronics, vol. 62, no. 2, pp. 910- 921, Feb. 2015.

[3] J. V. M. Caracas, G. d. C. Farias, L. F. M. Teixeira and L. A. d. S. Ribeiro, “ Implementation of a High-Efficiency, High-Lifetime, and Low-Cost Converter for an Autonomous Photovoltaic Water Pumping System, ” in IEEE Transactions on Industry Applications, vol. 50, no. 1, pp. 631-641, Jan.-Feb. 2014.

[4] Tae-Hyung Kim and M. Ehsani, “Sensorless control of the BLDC motors from near-zero to high speeds, ” in IEEE Transactions on Power Electronics, vol. 19, no. 6, pp. 1635-1645, Nov. 2004.

[5] S. Dusmez, A. Khaligh, M. Krishnamurthy, E. Ugur and M. Uzunoglu, “Sensorless control of BLDCs for all speed ranges with minimal components, ”International Aegean Conference on Electrical Machines and Power Electronics and Electromotion, Joint Conference, Istanbul, 2011, pp. 626-631

Online Estimation Method of DC-Link Capacitors for Reduced DC-Link Capacitance IPMSM Drives

ABSTRACT:

 In order to extend the lifetime and save the system cost, the film capacitor is applied in the DC-link of IPMSM drives. Many active damping control methods have been carried out to improve the drive system stability, which need the accurate value of the DC-link film capacitor. In this letter, an online DC-link capacitance estimation method is investigated for reduced capacitance IPMSM drives, which does not need any additional signal injection or sensor. The power coupling characteristics are analyzed to obtain the instantaneous power of the DC-link capacitor from the inverter and the grid sides. The band-pass filter is applied to extract the DC-link voltage and capacitor power with twice the frequency of the grid voltage. The DC-link capacitance could be estimated by the fundamental component of the DC-link voltage. The proposed method can be used for different kinds of load types and motor types of the drive system. Experimental results are performed to verify the estimation method, and the estimation error is within 1%.

KEYWORDS:

 

1.      Online capacitance estimation

2.      Motor drive

3.      Online capacitance estimation

4.      Reduced DC-link capacitance

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig. 1. Block diagram of DC-link capacitance estimation.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Experimental results when the motor operates at 1800rpm. (a) Waveforms of grid power, inverter power, capacitor power and its fundamental component. (b) Waveforms of the DC-link voltage, the product of DC-link voltage and its derivative, and the fundamental component of the product M. (c) Detailed waveform of the fundamental component of capacitor power, M, and the estimated DC-link capacitance.

 

Fig. 3. Experimental results when the motor operates at 4800rpm. (a) Waveforms of grid power, inverter power, capacitor power, and its fundamental component. (b) Waveforms of the DC-link voltage, the product of DC-link voltage and its derivative, and the fundamental component of the product M. (c) Detailed waveform of the fundamental component of capacitor power, M, and the estimated DC-link capacitance.

 

Fig. 4. Experimental results when the motor operates at 3000rpm and the DC-link capacitance is 59.5μF. (a) Waveforms of grid power, inverter power, capacitor power and its fundamental component. (b) Waveforms of the DC-link voltage, the product of DC-link voltage and its derivative, and the fundamental component of the product M. (c) Detailed waveform of the fundamental component of capacitor power, M, and the estimated DC-link capacitance.

  

CONCLUSION:

As for the reduced DC-link capacitance IPMSM drive system, a real-online DC-link capacitance estimation method is investigated in this letter, which does not need an additional signal injection. The power coupling characteristics are analyzed, and the instantaneous DC-link capacitor power is obtained. The DC-link capacitance could be estimated by the ratio of the fundamental component of DC-link capacitor power and that of the product between DC-link voltage and its derivative term. Moreover, the proposed method only depends on the DC-link voltage and the instantaneous DC-link capacitor power, which benefits its application in other motor type and load type reduced DC-link capacitance motor drive system. Experimental results verify the effectiveness of the proposed DC-link capacitance estimation method, which could realize the estimation precision within an error of 1% for the several tens microfarad of DC-link capacitance.

REFERENCES:

 

[1] Y. Zhang, Z. Yin, J. Liu, R. Zhang and X. Sun, “IPMSM Sensorless Control Using High-Frequency Voltage Injection Method With Random Switching Frequency for Audible Noise Improvement,” IEEE Trans. Ind. Electron., vol. 67, no. 7, pp. 6019-6030, Jul. 2020.

[2] K. Liu and Z. Zhu, “Fast Determination of Moment of Inertia of Permanent Magnet Synchronous Machine Drives for Design of Speed Loop Regulator,” IEEE Trans. Control Syst. Technol., vol. 25, no. 5, pp. 1816-1824, Sept. 2017.

[3] J. Hang, H. Wu, S. Ding, Y. Huang and W. Hua, “Improved Loss Minimization Control for IPMSM Using Equivalent Conversion Method,” IEEE Trans. Power Electron., vol. 36, no. 2, pp. 1931-1940, Feb. 2021

[4] K. Abe, H. Haga, K. Ohishi and Y. Yokokura, “Current ripple suppression control based on prediction of resonance cancellation voltage for electrolytic-capacitor-less inverter,” IEEJ J. Ind. Appl., vol. 6, no. 1, pp. 1-11, 2017.

[5] Y. Zhou, W. Huang, and F. Hong, “Single-phase input variable-speed AC motor system based on electrolytic capacitor-less single-stage boost three-phase inverter,” IEEE Trans. Power Electron., vol. 31, no. 10, pp. 7043-7052, Oct. 2016.

 

Grid-Connected Induction Motor Using a Floating DC-Link Converter Under Unbalanced Voltage Sag

ABSTRACT:

This article proposes a series compensator with unbalanced voltage sag ride-through capability applied to grid connected induction motors. A conventional three-phase voltage source inverter (VSI) is intended to regulate the motor voltages. The VSI is connected in series with the grid and a three-phase machine with open-ended windings. The proposed system is suitable for applications in which no frequency variation is required, like large pumps or fans. The VSI dc-link voltage operates as a floating capacitor through the energy minimized compensation (EMC) technique, in which there is no dc source or injection transformer. The motor load condition determines the minimum grid voltage positive component (sag severity) to keep EMC operation. Meanwhile, a voltage unbalance may increase the dc-link voltage requirements. A 1.5-hp four-pole induction motor has been used to verify the ride-through capability of the proposed compensator under grid voltage disturbances. A total harmonic distortion (THD) analysis of grid currents demonstrates that the proposed system provides low THD even if no passive filter is used. The operating principle, converter output voltage analysis, pulse width modulation technique, control strategy, and components ratings are discussed as well. Simulation and experimental results are presented to demonstrate the feasibility of the system.

KEYWORDS:

1.      Floating capacitor

2.      Induction motor

3.      Series compensator

4.      Unbalanced voltage sag

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

  

Fig. 1. Block diagram of feedback small-signal model.

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation waveforms at the steady state and half load with perphase grid (vga ) and load (vla ) voltages, as well as the converter’s line-to-line voltage (vcab ).

Fig. 3. Simulation waveforms with the proposed series compensator under balanced voltage sag at half load. (a) Rated grid voltages. (b) Three-phase voltage sag of 80%.

Fig. 4. Simulation waveforms with the proposed series compensator under unbalanced voltage sag:Fd = 15%and half load. (a) Grid voltages and currents. (b) DC-link voltage, torque, and speed.

CONCLUSION:

The proposed system has unbalanced voltage sag ride-through capability, being suitable for grid-connected induction motors applications. Indeed, the simulation and experimental results supported the theoretical analysis. A conventional three-phase VSI using a floating dc-link capacitor has been applied as a series compensator. Besides that, the proposed system does not require any additional passive filter, injection transformer, or extra power supply. A conventional three-phase H-bridge converter to compensate balanced grid voltage disturbances has recently been proposed in the literature. Compared to the conventional solution, the proposed one has a lower number of components, a single dc link, and can deal with unbalanced voltages without a complex control strategy. The higher dc-link voltage requirement of the proposed series compensator was highlighted as its main drawback. Although the proposed solution provided higher THD of grid currents, its levels were acceptable. Hence, the proposed system can be easily integrated along with standard squirrel-cage induction motors when no frequency variation is required.

REFERENCES:

[1] H. G. Sarmiento and E. Estrada, “A voltage sag study in an industry with adjustable speed drives,” IEEE Ind. Appl. Mag., vol. 2, no. 1, pp. 16–19, Jan. 1996.

[2] K. Pietilainen, L. Harnefors, A. Petersson, and H. Nee, “DC-link stabilization and voltage sag ride-through of inverter drives,” IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1261–1268, Jun. 2006.

[3] A. H. Bonnett and H.M. Glatt, “Ten things you should know about electric motors: Their installation, operation, and maintenance,” IEEE Ind. Appl. Mag., vol. 24, no. 6, pp. 25–36, Nov. 2018.

[4] G.C. Jaiswal, M. S. Ballal, D. R. Tutakne, and H. M. Suryawanshi, “Impact of power quality on the performance of distribution transformers: A fuzzy logic approach to assessing power quality,” IEEE Ind. Appl.Mag., vol. 25, no. 5, pp. 8–17, Sep. 2019.

[5] “IEEE Recommended Practice for Monitoring Electric Power Quality”, IEEE Std 1159-2009 (Revision of IEEE Std 1159-1995), pp. c 1–81, Jun. 2009.

Current and Speed Sensor Fault Diagnosis Method Applied to Induction Motor Drive

ABSTRACT:

The paper proposes a novel approach based on a current space vector derived from measured stator currents to diagnose speed and current sensor failures in the field-oriented control of induction motor drives. A comparison algorithm between the reference and measured rotor speed is used to detect the speed sensor faults. A counter is added to eliminate the influence of the encoder noise in the diagnosis method. In this approach, estimated quantities are not used in the proposed speed sensor fault diagnosis strategy, which increases the independence between the diagnosis stages in the fault-tolerant control (FTC) method. Moreover, in order to discriminate between the speed sensor faults and the current sensor faults, a new approach combining the current space vector and a delay function is proposed to reliably determine the current sensor failures. The MATLAB-Simulink software was used to verify the idea of the proposed method. Practical experiments with an induction motor drive controlled by DSP  were performed to demonstrate the feasibility of this method in practice. The simulation and experimental results prove the effectiveness of the proposed diagnosis method for induction motor drives.

KEYWORDS:

1.      Fault-tolerant control

2.      Diagnosis

3.       Induction motor

4.       FOC

5.      Sensorless control

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

 

Figure 1. Block Diagram of FTC Unit.

 EXPECTED SIMULATION RESULTS:

 

Figure 2. Simulation Results - Speed Sensor Fault _ FTC.

Figure 3. Simulation Results _ Scaling Current Sensor Fault _ FTC.

 

 

Figure 4. Simulation Results _ Total Current Sensor Fault _ FTC.

 

CONCLUSION:

This paper presents a novel diagnosis method for the speed and current sensor fault-tolerant control of induction motor drives. The proposed method has proven its effectiveness in dealing with multi-type sensor failures. The speed sensor fault diagnosis algorithm can reliably detect the inaccuracy of the speed sensor signals without interference by random pulse noises. The loss of the current sensor signals, which is the most severe current sensor fault, is quickly detected by the delay-algorithm. Other types of current sensor failures is reliably identified without misunderstanding with a speed sensor fault. The proposed diagnosis algorithm is simpler than other existing detection methods, and thus, the computational hardware system executes faster as well as cheaper due to the lower calculation burden for the same operating conditions. The simulation and experimental results have demonstrated the efficiency of the proposed method. Further research can be implemented to improve the diagnosis of the sensor faults in transient states.

REFERENCES:

[1] A. Gouichiche, A. Safa, A. Chibani, and M. Tadjine, ``Global fault-tolerant control approach for vector control of an induction motor,'' Int. Trans. Electr. Energy Syst., vol. 30, no. 8, Aug. 2020, Art. no. e12440, doi: 10.1002/2050-7038.12440.

[2] D. Diallo, M. E. H. Benbouzid, and M. A. Masrur, ``Special section on condition monitoring and fault accommodation in electric and hybrid propulsion systems,'' IEEE Trans. Veh. Technol., vol. 62, no. 3, pp. 962_964, Mar. 2013, doi: 10.1109/TVT.2013.2245731.

[3] A. A. Amin and K. M. Hasan, ``A review of fault tolerant control systems: Advancements and applications,'' Measurement, vol. 143, pp. 58_68, Sep. 2019, doi: 10.1016/j.measurement.2019.04.083.

[4] A. Raisemche, M. Boukhnifer, C. Larouci, and D. Diallo, ``Two active fault-tolerant control schemes of induction-motor drive in EV or HEV,'' IEEE Trans. Veh. Technol., vol. 63, no. 1, pp. 19_29, Jan. 2014, doi:  10.1109/TVT.2013.2272182.

[5] Y. Azzoug, A. Menacer, R. Pusca, R. Romary, T. Ameid, and A. Ammar, ``Fault tolerant control for speed sensor failure in induction motor drive based on direct torque control and adaptive stator _ux observer,'' in Proc. Int. Conf. Appl. Theor. Electr. (ICATE), Oct. 2018, pp. 1_6.