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    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106 A PMBLDCM Speed Control By Using A Buck DC-DC Converter And Voltage Control Anitha Arumalla, Student M.Lokya, M.Tech Electrical Engineering Department, Mother Therisa Institute of Science and Technolgy, Sathupalli -507303, IndiaAbstract A buck half-bridge DC-DC converter is thereby poor efficiency and reduced life of theused as a single-stage power factor correction motor. Moreover, the temperature of the air(PFC) converter for feeding a voltage source conditioned zone is regulated in a hysteresis band.inverter (VSI) based permanent magnet Therefore, improved efficiency of the Air-Conbrushless DC motor (PMBLDCM) drive. The system will certainly reduce the cost of living andfront end of this PFC converter is a diode bridge energy demand to cope-up with ever-increasingrectifier (DBR) fed from single-phase AC mains. power crisis.The PMBLDCM is used to drive a compressor A PMBLDCM which is a kind of three-load of an air conditioner through a three-phase phase synchronous motor with permanent magnetsVSI fed from a controlled DC link voltage. The (PMs) on the rotor and trapezoidal back EMFspeed of the compressor is controlled to achieve waveform, operates on electronic commutationenergy conservation using a concept of the accomplished by solid state switches. It is poweredvoltage control at DC link proportional to the through a three-phase voltage source inverter (VSI)desired speed of the PMBLDCM. Therefore the which is fed from single-phase AC supply using aVSI is operated only as an electronic commutator diode bridge rectifier (DBR) followed byof the PMBLDCM. The stator current of the smoothening DC link capacitor. The compressorPMBLDCM during step change of reference exerts constant torque (i.e. rated torque) on thespeed is controlled by a rate limiter for the PMBLDCM and is operated in speed control modereference voltage at DC link. The proposed to improve the efficiency of the Air-Con system.PMBLDCM drive with voltage control based Since, the back-emf of the PMBLDCM isPFC converter is designed, modeled and its proportional to the motor speed and the developedperformance is simulated in Matlab-Simulink torque is proportional to its phase current [1-4],environment for an air conditioner compressor therefore, a constant torque is maintained by adriven through a 1.5 kW, 1500 rpm PMBLDC constant current in the stator winding of themotor. The evaluation results of the proposed PMBLDCM whereas the speed can be controlled byspeed control scheme are presented to varying the terminal voltage of the motor. Based ondemonstrate an improved efficiency of the this logic, a speed control scheme is proposed in thisproposed drive system with PFC feature in wide paper which uses a reference voltage at DC linkrange of the speed and an input AC voltage. proportional to the desired speed of the PMBLDC motor. However, the control of VSI is only forIndex Terms— PFC, PMBLDCM, Air electronic commutation which is based on the rotorconditioner, Buck Half-bridge converter, Voltage position signals of the PMBLDC motor.control, VSI. The PMBLDCM drive, fed from a single- phase AC mains through a diode bridge rectifierI. INTRODUCTION (DBR) followed by a DC link capacitor, suffers from power quality (PQ) disturbances such as poorPERMANENT magnet brushless DC motors power factor (PF), increased total harmonic(PMBLDCMs) are preferred motors for a distortion (THD) of current at input AC mains andcompressor of an air-conditioning (Air-Con) system its high crest factor (CF). It is mainly due todue to its features like high efficiency, wide speed uncontrolled charging of the DC link capacitorrange and low maintenance requirements [1-4]. The which results in a pulsed current waveform having aoperation of the compressor with the speed control peak value higher than the amplitude of theresults in an improved efficiency of the system while fundamental input current at AC mains. Moreover,maintaining the temperature in the air-conditioned the PQ standards for low power equipments such aszone at the set reference consistently. Whereas, the IEC 61000-3-2 [5], emphasize on low harmonicexisting air conditioners mostly have a single-phase contents and near unity power factor current to beinduction motor to drive the compressor in „on/off‟ drawn from AC mains by these motors. Therefore,control mode. This results in increased losses due to use of a power factor correction (PFC) topologyfrequent „on/off‟ operation with increased amongst various available topologies [6-14] ismechanical and electrical stresses on the motor, almost inevitable for a PMBLDCM drive. 1097 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106Most of the existing systems use a boost required only at the commutation points, e.g.,converter for PFC as the front-end converter every 60°electrical in the three-phase [1-4]. Theand an isolated DC-DC converter to produce rotor position of PMBLDCM is sensed usingdesired output voltage constituting a two-stage Hall effect position sensors and used toPFC drive [7-8]. The DC-DC converter used in generate switching sequence for the VSI asthe second stage is usually a flyback or forward shown in Table-I.converter for low power applications and a full-bridge converter for higher power applications. The DC link voltage is controlled by aHowever, these two stage PFC converters have half-bridge buck DC-DC converter based on thehigh cost and complexity in implementing two duty ratio (D) of the converter. For a fast andseparate switch-mode converters, therefore a effective control with reduced size of magneticssingle stage converter combining the PFC and and filters, a high switching frequency is used;voltage regulation at DC link is more in however, the switching frequency (fs) is limiteddemand. The single-stage PFC converters by the switching device used, operating poweroperate with only one controller to regulate the level and switching losses of the device. MetalDC link voltage along with the power factor oxide field effect transistors (MOSFETs) arecorrection. The absence of a second controller used as the switching device for high switchinghas a greater impact on the performance of frequency in the proposed PFC converter.single-stage PFC converters and requires a However, insulated gate bipolar transistorsdesign to operate over a much wider range of (IGBTs) are used in VSI bridge feedingoperating conditions. PMBLDCM, to reduce the switching stress, as it operates at lower frequency compared to PFC For the proposed voltage controlled drive, a switches.half-bridge buck DC-DC converter is selectedbecause of its high power handling capacity as The PFC control scheme uses a currentcompared to the single switch converters. control loop inside the speed control loop withMoreover, it has switching losses comparable to current multiplier approach which operates inthe single switch converters as only one switch continuous conduction mode (CCM) withis in operation at any instant of time. It can be average current control. The control loop beginsoperated as a single-stage power factor with the comparison of sensed DC link voltagecorrected (PFC) converter when connected with a voltage equivalent to the referencebetween the VSI and the DBR fed from single- speed. The resultant voltage error is passedphase AC mains, besides controlling the voltage through a proportional -integral (PI) controllerat DC link for the desired speed of the Air-Con to give the modulating current signal. Thiscompressor. A detailed modeling, design and signal is multiplied with a unit template of inputperformance evaluation of the proposed drive AC voltage and compared with DC currentare presented for an air conditioner compressor sensed after the DBR. The resultant currentdriven by a PMBLDC motor of 1.5 kW, 1500 error is amplified and compared with saw-toothrpm rating. carrier wave of fixed frequency (fs) in unipolar scheme (as shown in Fig.2) to generate theII. PROPOSED SPEED CONTROL PWM pulses for the half-bridge converter. ForSCHEME OF PMBLDC the current control of the PMBLDCM duringMOTOR FOR AIR CONDITIONER step change of the reference voltage due to the The proposed speed control scheme (as change in the reference speed, a voltageshown in Fig. 1) controls reference voltage at gradient less than 800 V/s is introduced for theDC link as an equivalent reference speed, change of DC link voltage, which ensures thethereby replaces the conventional control of the stator current of the PMBLDCM within themotor speed and a stator current involving specified limits (i.e. double the rated current).various sensors for voltage and current signals.Moreover, the rotor position signals are used togenerate the switching sequence for the VSI asan electronic commutator of the PMBLDCmotor. Therefore, rotor-position information is 1098 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106 filter restricts the inductor peak to peak ripple current ( ILo) within specified value for the given switching frequency (fs), whereas, the capacitance (Cd) is calculated for a specified ripple in the output voltage ( VCd) [7-8]. The output filter inductor and capacitor are given as Lo= (0.5-D)Vdc/{fs( ILo) } (3) Cd=Io/(2ωΔVCd) (4) The PFC converter is designed for a base DC link voltage of V dc = 400 V at Vin = 198 V from Vs = 220 Vrms. The turns ratio of the high frequency transformer (N2/N 1) is taken as 6:1 to maintain the desired DC link voltage at low input AC voltages typically at 170V. Other design data are fs = 40Figure 1. Control schematic of Proposed Bridge- kHz, Io = 4 A, VCd= 4 V (1% of Vdc), ILo= 0.8 Abuck PFC converter fed PMBLDCM drive (20% of Io). The design parameters are calculated as Lo=2.0 mH, Cd=1600 µF.III.DESIGN OF PFC BUCK HALF- TABL VSI SWITCHING SEQUENCE BASED E I. ON THE HALL EFFECTBRIDGE CONVERTER SENSORBASED PMBLDCM DRIVE The proposed PFC buck half-bridge SIGNALSconverter is designed for a PMBLDCM drive withmain considerations on PQ constraints at AC H E E Emains and allowable ripple in DC link voltage. Ha b Hc a b c S1 S2 S3 S4 S5 S6The DC link voltage of the PFC converter is given 0 0 0 0 0 0 0 0 0 0 0 0as, 0 0 1 0 -1 +1 0 0 0 1 1 0Vdc = 2 (N2/N1) Vin D and N2= N21=N22 (1) where 0 1 0 -1 +1 0 0 1 1 0 0 0N1, N21, N22 are number of turns in primary, 0 1 1 -1 0 +1 0 1 0 0 1 0secondary upper and lower windings of the high 1 0 0 +1 0 -1 1 0 0 0 0 1frequency (HF) isolation transformer, respectively. 1 0 1 +1 -1 0 1 0 0 1 0 0 1 1 0 0 +1 -1 0 0 1 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 I MODELING OF THE PROPOSED PMBLDCM V. DRIVE The main components of the proposed PMBLDCM drive are the PFC converter and PMBLDCM drive, which are modeled by mathematical equations and the complete drive is represented as a combination of these models. A. PFC Converter The modeling of the PFC converter consists of the modeling of a speed controller, aFigure 2. PWM control of the buck half-bridge reference current generator and a PWM controllerconverter as given below.Vin is the average output of the DBR for a givenAC input voltage (Vs) related as, 1) Speed Controller: The speed controller, the prime component of this control scheme, is aVin = 2√2Vs/π (2) proportional-integral (PI) controller which closely tracks the reference speed as an equivalentA ripple filter is designed to reduce the ripples reference voltage. If at kth instant of time, V*dc(k) isintroduced in the output voltage due to high reference DC link voltage, Vdc(k) is sensed DC linkswitching frequency for constant of the buck half- voltage then the voltage error Ve(k) is calculatedbridge converter. The inductance (Lo) of the ripple as, 1099 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106 Ve(k) =V*dc(k)-Vdc(k) (5) as „o‟ in Fig. 3. The voltages van, vbn, vcn are voltages of three-phases with respect to neutral The PI controller gives desired control point (n) and Vdc is the DC link voltage. S= 1 and signal after processing this voltage error. The 0 represent „on‟ and „off‟ position of respective output of the controller Ic(k) at kth instant is given IGBTs of the VSI and considered in a similar way as, for other IGBTs of the VSI i.e. S3- S6. Ic (k) = Ic (k-1) + Kp{Ve(k) – Ve(k-1)} + KiVe(k) Using similar logic vbo, vco, vbn, vcn are (6) where Kp and Ki are the proportional and generated for other two phases of the VSI feeding integral gains of the PI controller. PMBLDC motor. 2) Reference Current Generator: The reference 3) PMBLDC Motor:The PMBLDCM is input current of the PFC converter is denoted by represented in the form of a set of differential idc* and given as, i*dc = Ic (k) uVs (7) where uVs is equations [3] given as, the unit template of the voltage at input AC mains, van = Ria + pλa +ean (15) calculated as, uVs = vd/Vsm; vd = |vs|; vs= Vsm sin ωt (8) where Vsm is the amplitude of the voltage and vbn = Rib + pλb +ebn (16) ω is frequency in rad/sec at AC mains. vcn = Ric + pλc +ecn (17) 3) PWM Controller:The reference input current where p is a differential operator (d/dt), of the buck half-bridge converter (idc*) is ia, ib, ic are three-phase currents, λa, λb, λc are flux compared with its sensed current (idc) to generate linkages and ean, ebn, ecn are phase to neutral back the current error idc=(idc* - idc). This current error emfs of PMBLDCM, in respective phases, R is is amplified by gain kdc and compared with fixed resistance of motor windings/phase. frequency (fs) saw-tooth carrier waveform md(t) (as shown in Fig.2) in unipolar switching mode [7] Therefore, the electromagnetic torque is expressed to get the switching signals for the MOSFETs of as, the PFC buck half-bridge converter as, Te = Kb{fa(θ) ia + fb(θ) ib+ fc(θ) ic} (31) id md The mechanical equation of motion in speedIf kdc c > (t) then SA = 1 else SA = 0 (9) derivative form is given as, i pω = (P/2) (Te-TL-Bω)/(J) (32) d mdIf -kdc c > (t) then SB = 1 else SB = 0 (10) The derivative of the rotor position angle is given as, pθ = ω (33) where SA, SB are upper and lower switches of the half-bridge converter as shown in where P is no. poles, TL is load torque in Fig. 1 and their values „1‟ and „0‟ represent „on‟ Nm, J is moment of inertia in kg-m2 and B is and „off‟ position of the respective MOSFET of friction coefficient in Nms/Rad. the PFC converter. These equations (15-33) represent the dynamic B. PMBLDCM Drive model of the PMBLDC motor. The PMBLDCM drive consists of an electronic commutator, a VSI and a PMBLDC motor. 1) Electronic Commutator: The electronic commutator uses signals from Hall effect position sensors to generate the switching sequence for the voltage source inverter based on the logic given in Table I. 2) Voltage Source Inverter: Fig. 3 shows an equivalent circuit of a VSI fed PMBLDCM. The output of VSI to be fedto phase „a‟ of the PMBLDC motor is given as, fo S vao = (Vdc/2) r 1 =1 (11) fo S Figure 3. Equivalent Circuit of a VSI fed vao = (-Vdc/2) r 2 =1 (12) PMBLDCM Drive The flux linkages are represented as, vao = 0 for S1 = 0, and S2 = 0 (13) van = vao – vno (14) λa = Lia - M (ib + ic) (18) where vao, vbo, vco, and vno are voltages of λb = Lib - M (ia + ic) (19) the three-phases and neutral point (n) with respect to virtual mid-point of the DC link voltage shown λc = Lic - M (ib + ia) (20) 1100 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106 where L is self-inductance/phase, M is The compressor load is considered as a constant mutual inductance of motor winding/phase. Since torque load equal to rated torque with the speed the PMBLDCM has no neutral connection, control required by air conditioning system. A 1.5 therefore, kW rating PMBLDCM is used to drive the air ia + ib + ic = 0 (21) conditioner compressor, speed of which is From Eqs. (14-21) the voltage between controlled effectively by controlling the DC link neutral terminal (n) and mid-point of the DC link voltage. The detailed data of the motor and (o) is given as, simulation parameters are given in Appendix. The performance of the proposed PFC drive isvno = {vao +vbo + vco – (ean +ebn +ecn)}/3 (22) evaluated on the basis of various parameters suchFrom Eqs. (18-21), the flux linkages are given as, as total harmonic distortion (THDi) and the crestλa = (L+M) i a, λb = (L+M) ib, λc = (L+M) ic, (23) factor (CF) of the current at input AC mains, From Eqs. (15-17 and 23), the current derivatives displacement power factor (DPF), power factor in generalized state space form is given as, (PF) and efficiency of the drive system (ηdrive) at different speeds of the motor. Moreover, these parameters are also evaluated for variable input pix = (vxn - ix R – exn)/(L+M) (24) AC voltage at DC link voltage of 416 V which is where x represents phase a, b or c. equivalent to the rated speed (1500 rpm) of the PMBLDCM. The results are shown in Figs. 4-9 V. PERFORMANCE EVALUATION and Tables II-III to demonstrate the effectiveness OF PROPOSED PFC DRIVE of the proposed PMBLDCM drive in a wide range The proposed PMBLDCM drive is of speed and input AC voltage. modeled in Matlab-Simulink environment and evaluated for an air conditioning compressor load. develope electromagneti i The performance of the proposed PMBLDCM drive The d c torque Te n the fed from 220 V AC mains during starting at rated torque and PMBLDCM is given as, 900 rpm speed is shown in Fig. 4a. A rate limiter of 800 V/s is Te = (ean ia + ebn ib +ecn ic)/ ω (25) introduced in the reference voltage to limit the starting current where ω is motor speed in rad/sec, of the motor as well as the charging current of the DC link capacitor. The PI controller closely tracks the reference The back emfs may be expressed as a function of speed rotor so that the motor attains reference speed smoothly within 0.35 position (θ) as, sec while keeping the stator current within the desired limits exn= Kb fx(θ) ω (26) i.e. double the rated value. The current (is) waveform at input where x can be phase a, b or c and accordingly fx(θ) A main i phas wit suppl voltag represents C s is n e h the y e (vs) function of rotor position with a maximum value ±1, identical demonstrating nearly unity power factor during the starting. to trapezoidal induced emf given as, Performance under Speed B. Control fa(θ) = 1 for 0 < θ < 2π/3 (27) Figs. 4-6 show the performance of the proposed fa(θ) = {(6/ π)( π- θ)}- PMBLDCM drive under the speed control at constant 1 for 2π/3 < θ < π (28) rated torque (9.55 Nm) and 220 V AC mains supply voltage. These fa(θ) = -1 for π < θ < 5π/3 (29) results are categorized as performance during transient fa(θ) = {(6/π)(θ - and 2π)}+1 for 5π/3 < θ < 2π (30) steady state conditions. 1101 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106The functions fb(θ) and fc(θ) are similar to fa(θ)with a phase difference of 120º and 240ºrespectively.1) Transient Condition: Figs. 4b-c show theperformance of the drive during the speedcontrol of the compressor. TheFig. 4a: Starting performance of the PMBLDCM drive at 900 rpm.Fig. 4b: PMBLDCM drive under speed variation from 900 rpm to 1500 rpm. 1102 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106 Fig. 4c: PMBLDCM drive under speed variation from 900 rpm to 300 rpm. Figure 4. Performance of the Proposed PMBLDCM drive under speed variation at 220 VAC input. Fig. 5a: Performance of the PMBLDCM drive at 300 rpm. Fig. 5b: Performance of the PMBLDCM drive at 900 rpm. Fig. 5c: Performance of the PMBLDCM drive at rated speed (1500 rpm). Figure 5. Performance of the PMBLDCM drive under steady state condition at 220 VAC input. 1103 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106reference speed is changed from 900 rpm to 1500rpm for the rated load performance of thecompressor; from 900 rpm to 300 rpm forperformance of the compressor at light load. It isobserved that the speed control is fast and smoothin either direction i.e. acceleration or retardationwith power factor maintained at nearly unity Figure 7. PQ parameters of PMBLDCM drivevalue. Moreover, the stator current of PMBLDCM under speed control at rated torque and 220 VACis within the allowed limit (twice the rated current) inputdue to the introduction of a rate limiter in thereference voltage.2) Steady State Condition:The speed control ofthe PMBLDCM driven compressor under steadystate condition is carried out for different speedsand the results are shown in Figs. 5-6 and Table-IIto demonstrate the effectiveness of the proposeddrive in wide speed range. Figs.5a-c show voltage(vs) and current (is) waveforms at AC mains, DClink voltage (Vdc), speed of the motor (N), Fig. 8a. At 300 rpm Fig. 8b. At 900 rpm Fig.developed electromagnetic torque of the motor 8c. At 1500 rpm(Te), the stator current of the PMBLDC motor for Figure 8. Current waveform at AC mains and itsphase „a‟ (Ia), and shaft power output (Po) at 300 harmonic spectra of the PMBLDCM drive underrpm, 900 rpm and 1500 rpm speeds. Fig. 6a shows steady state condition at rated torque and 220 VAClinear relation between motor speed and DC linkvoltage. Since the reference speed is decided by TABLE II. PERFORMANCE OF DRIVEthe reference voltage at DC link, it is observed that UNDER SPEED CONTROL AT 220 V ACthe control of the reference DC link voltage INPUTcontrols the speed of the motor instantaneously. Spee TH ηdriv Fig.6b shows the improved efficiency of the drive d VDC Di DPF PF e Loadsystem (ηdrive) in wide range of the motor speed. (rpm (% ) (V) ) (%) (%)C. Power Quality Performance 4.8 The performance of the proposed 300 100 4 0.9999 0.9987 74.2 20.0PMBLDCM drive in terms of various PQ 3.9parameters such as THDi, CF, DPF, PF is 400 126 4 0.9999 0.9991 79.1 26.7summarized in Table-II and shown in Figs. 7-8. 3.3Nearly unity power factor (PF) and reduced THD 500 153 3 0.9999 0.9993 81.8 33.3of AC mains current are observed in wide speed 2.9range of the PMBLDCM as shown in Figs. 7a-b. 600 179 2 0.9999 0.9995 83.8 40.0The THD of AC mains current remains less than5% along with nearly unity PF in wide range of 2.6speed as well as load as shown in Table-II and 700 205 3 0.9999 0.9996 85.3 46.6Figs. 8a-c. 2.4 800 232 0 0.9999 0.9996 86.1 53.3 2.2 900 258 4 0.9999 0.9996 87.0 60.0 2.1 1000 284 6 0.9999 0.9997 87.6 66.6 2.0 1100 310 9 0.9999 0.9997 88.1 73.3 2.0 1200 337 3 0.9999 0.9997 88.1 80.0 2.0 1300 363 5 0.9999 0.9997 88.2 86.6Fig. 6a. DC link voltage with speed Fig. 6b.Efficiency with load 2.0 1400 390 7 0.9999 0.9997 88.1 93.3Figure 6. Performance of the proposed PFC drive 2.0under speed control at rated torque and 220 VAC 1500 416 9 0.9999 0.9997 88.1 100.0 1104 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106D. Performance under Variable Input AC VI. CONCLUSIONVoltage A new speed control strategy of a Performance evaluation of the proposed PMBLDCM drive is validated for a compressorPMBLDCM drive is carried out under varying load of an air conditioner which uses the referenceinput AC voltage at rated load (i.e. rated torque speed as an equivalent reference voltage at DCand rated speed) to demonstrate the operation of link. The speed control is directly proportional toproposed PMBLDCM drive for air conditioning the voltage control at DC link. The rate limitersystem in various practical situations as introduced in the reference voltage at DC linksummarized in Table-III. effectively limits the motor current within the desired value during the transient condition Figs. 9a-b show variation of input current (starting and speed control). The additional PFCand its THD at AC mains, DPF and PF with AC feature to the proposed drive ensures nearly unityinput voltage. The THD of current at AC mains is PF in wide range of speed and input AC voltage.within specified limits of international norms [5] Moreover, power quality parameters of thealong with nearly unity power factor in wide range proposed PMBLDCM drive are in conformity to anof AC input voltage. International standard IEC 61000-3-2 [5]. The proposed drive has demonstrated good speed control with energy efficient operation of the drive system in the wide range of speed and input AC voltage. The proposed drive has been found as a promising candidate for a PMBLDCM driving Air- Con load in 1-2 kW power range. APPENDIX Rated Power: 1.5 kW, rated speed: 1500 rpm, rated current: 4.0 A, rated torque: 9.55 Nm, number of poles: 4, stator resistance (R): 2.8 Ω/ph.,Fig. 9a. Current at AC mains and its THD Fig. 9b. inductance (L+M): 5.21 mH/ph., back EMFDPF and PF Figure 9. PQ parameters with input constant (Kb): 0.615 Vsec/rad, inertia (J): 0.013AC voltage at 416 VDC (1500 rpm) Kg-m2. Source impedance (Zs): 0.03 pu, switching frequency of PFC switch (fs) = 40 kHz, capacitorsTABLE III. VARIATION OF PQ (C1= C2): 15nF, PI speed controller gains (Kp):PARAMETERS WITH INPUT AC VOLTAGE 0.145, (Ki): 1.45.(VS) AT 1500 RPM (416 VDC) VA TH Is ηdri REFERENCES C Di DPF PF CF (A) ve [1] Sanjeev Singh and Bhim Singh, A (V) (%) (%) Voltage controlled adjustable speed 17 PMBLDCM drive using a single-stage 0 2.88 0.9999 0.9995 1.41 10.4 84.9 PFC Half-Bridge converter, IEEE 2010. 18 [2] T. Kenjo and S. Nagamori, Permanent 0 2.59 0.9999 0.9996 1.41 9.7 85.8 Magnet Brushless DC Motors, Clarendon 19 Press, oxford, 1985. 0 2.40 0.9999 0.9996 1.41 9.2 86.3 [3] Sanjeev Singh and Bhim Singh, A 20 Voltage controlled adjustable speed 0 2.26 0.9999 0.9996 1.41 8.6 87.2 PMBLDCM drive using a single-stage 21 PFC Half-Bridge converter, IEEE 2010. 0 2.14 0.9999 0.9997 1.41 8.2 87.6 [4] T. J. Sokira and W. Jaffe, Brushless DC 22 Motors: Electronic Commutation and 0 2.09 0.9999 0.9997 1.41 7.7 88.1 Control, Tab Books USA, 1989. 23 [5] J. R. Hendershort and T. J. E. Miller, 0 2.07 0.9999 0.9997 1.41 7.4 88.2 Design of Brushless Permanent-Magnet 24 Motors, Clarendon Press, Oxford, 1994. 0 2.02 1.0000 0.9998 1.41 7.1 88.4 [6] J. F. Gieras and M. Wing, Permanent 25 Magnet Motor Technology – Design and 0 1.99 1.0000 0.9998 1.41 6.8 88.7 Application, Marcel Dekker Inc., New York, 2002. 26 [7] Limits for Harmonic Current Emissions 0 2.01 1.0000 0.9998 1.41 6.5 88.7 (Equipment input current ≤16 A per 27 phase), International Standard IEC 61000- 0 2.01 1.0000 0.9998 1.41 6.2 89.0 3-2, 2000. 1105 | P a g e
    • Anitha Arumalla, M.Lokya, M.Tech / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 5, September- October 2012, pp.1097-1106[8] B. Singh, B. N. Singh, A. Chandra, K. Al- Haddad, A. Pandey and D. P. Kothari, “A review of single-phase improved power quality AC-DC converters,” IEEE Trans. Industrial Electron., vol. 50, no. 5, pp. 962 – 981, oct. 2003.[9] N. Mohan, T. M. Undeland and W. P. Robbins, “Power Electronics: Converters, Applications and Design,” John Wiley, USA, 1995.[10] A. I. Pressman, Switching Power Supply Design, McGraw Hill, New York, 1998.[11] P.J. Wolfs, “A current-sourced DC-DC converter derived via the duality principle from the half-bridge converter,” IEEE Trans. Ind. Electron., vol. 40, no. 1, pp. 139 – 144, Feb. 1993.[12] J.Y. Lee, G.W. Moon and M.J. Youn, “Design of a power-factor-correction converter based on half-bridge topology,” IEEE Trans. Ind. Electron., vol. 46, no. 4, pp.710 – 723, Aug 1999.[13] J. Sebastian, A. Fernandez, P.J. Villegas, M.M. Hernando and J.M. Lopera, “Improved active input current shapers for converters with symmetrically driven transformer,” IEEE Trans. Ind. Appl., vol. 37, no. 2, pp. 592 – 600, March-April 2001.[14] A. Fernandez, J. Sebastian, M.M. Hernando and P. Villegas, “Small signal modelling of a half bridge converter with an active input current shaper,” in Proc. IEEE PESC, 2002, vol.1, pp.159 – 164.[15] S.K. Han, H.K. Yoon, G.W. Moon, M.J. Youn, Y.H. Kim and K.H. Lee, “A new active clamping zero-voltage switching PWM current-fed half-bridge converter,” IEEE Trans. Power Electron., vol. 20, no. 6, pp. 1271 – 1279, Nov. 2005.[16] R.T.Bascope, L.D.Bezerra, G.V.T.Bascope, D.S. Oliveira, C.G.C. Branco, and L.H.C. Barreto, “High frequency isolation on-line UPS system for low power applications,” in Proc. IEEE APEC’08, 2008, pp.1296 – 1302. 1106 | P a g e