R FACTOR CORRECTION FOR AIR CONDITIONING SYSTEMBYBRIDGELESS

Transcription

1 Volume 119 No , ISSN: (on-line version) url: POWER FACTOR CORRECTION FOR AIR CONDITIONING SYSTEMBYBRIDGELESS ijpam.eu CUK CONVERTER FED BLDC MOTOR K.Venkateshwari 1, R.Sathyapriya 2 Assistant Professor 1 2 Department of EEE, BIST, BIHER, Bharath University, Chennai. venkateshwari.eee@bharathuniv.ac.in because of single stage operation which has reduced number of components. A PFC and DC-link voltage control can be achieved in a single stage operation [11, 12]. Abstract This paper deals with bridgeless cuk converter operating in discontinuous inductor current mode (DICM) for single-stage power factor correction converter for a permanent magnet brushless dc motor (PMBLDCM).A three-phase voltagesource inverter is used as an electronic commutator to operate the PMBLDCM driving an air-conditioning system. The speed control of PMBLDC motor achieved by controlling the voltage at DC bus using single voltage sensor. The bridgeless cuk converter topology is used for obtaining low switching losses and low size heat sink is used for switches. Keywords Bridgeless cuk converter Permanent magnet brushless DC motor (PMBLDCM),Discontinous inductor current mode(dicm),power factor correction(pfc),voltage source inverter(vsi). I. INTRODUCTION The use of a permanent-magnet brushless dc motor (PMBLDCM) is used in low and medium power applications because of their high efficiency, wide speed range, high energy density,high torque/inertia ratio, low maintenance and wide range of speed control. The BLDC motor has three phase distributed winding on stator and permanent magnet on the rotor. There is no brushes used for commutation. It is an electronically commutated motor. The hall sensors are used for rotor position sensing and it is used for commutation state of voltage source inverter switches. The problems associated with mechanical commutator such as sparking, electromagnetic interference, wear and tear and noise problems in brush and commutator assembly are eliminated.bldc motors are used household equipments like air conditioners, washing machines,refrigerators,fansetc and it is also used in medical equipments, industrial tools, heating,ventilation and motion control systems. A BLDC motor has the developed torque proportional to its phase current and its back electromotive force (EMF), which is proportional to the speed [1] [4]. A constant current in its stator windings with variable voltage across its terminals maintains constant torque in a PMBLDCM under variable speed operation. A speed control scheme uses a reference voltage at dc link proportional to the desired speed of the permanent-magnet brushless direct current (PMBLDC) motor. The BLDC motor fed by a diode bridge rectifier (DBR) with a high value of DC-link capacitor results in highly distorted supply current and a poor factor [9]. Hence,a power factor corrected (PFC) converter is required for obtaining the improved PQ at the AC mains for a VSI-fed BLDC motor drive. Two stage PFC converters have been in normal practice in which one converter is used for the PFC operation which is typically a boost converter and other converter is used for the voltage control, selection of which depends upon the type of application [10]. This has more losses because of higher number of components and two switches. A single stage PFC converter has gained popularity Two basic modes of operation of a PFC converter, continuous conduction mode (CCM) and dis-continuous conduction mode (DCM) [11,12]. In CCM or DCM, the inductor s current or the voltage across intermediate capacitor in a PFC converter remains continuous or discontinuous in a switching period. The PFC converter operate in CCM, requires three sensors (two voltage, one current) while in DCM operation can be achieved by using a single voltage sensor [12]. The stresses on PFC converter switch operating in DCM are comparatively higher as compared with its operation in CCM. A PFC boost half-bridge-fed BLDC motor drive using a four switch VSI has been proposed by Madani et al. [13] Which uses a constant DC-link voltage with PWM switching of VSI and have high switching losses? Ozturk et al. [14] have proposed a PFC boost converter feeding a direct torque controlled (DTC)-based BLDC motor drive which requires higher number of sensors for DTC operation, have higher switching losses in PWM-VSI and increased complexity of the control unit. A similar configuration using a front-end cascaded buck boost converter-fed BLDC motor drive has been proposed by Wu and Tzou [15], which also confronts same difficulties. Gopalarathnam and Toliyat [16] have proposed an active PFC using a single ended primary inductance converter (SEPIC) for feeding a BLDC motor drive which again utilized a PWM-based VSI for speed control of BLDC motor which have switching losses corresponding to the switching frequency of PWM pulses. PFC Cuk converter operating in CCM for feeding a BLDC motor drive has been proposed by Singh and Singh [17], but it requires three sensors for DC-linkvoltage control and PFC operation and hence thistopologyis suited for high-power applications. This main objective of this paper is the development of cost effective motor drive which requires minimum sensors and has reduced switching losses in the VSI. Moreover, the proposed drive operates for improved PQ operation at AC mains over a wide range of speed control. II.PROPOSED BRIDGELESS CUK CONVERTER-FED BLDC MOTOR DRIVE Fig. 1 shows the bridgeless Cuk converter-fed BLDC motor driving an air conditioning compressor. The bridgeless Cuk converter is used to control the DC-link voltage (Vdc) of the VSI and to achieve a unity power factor at AC mains. To eliminate a DBR in the front end[18-22], a bridgeless converter topology is used which has an advantage of low conduction losses and thermal stress on the devices. A new approach of speed control by controlling the voltage at the DC link is used which utilizes a fundamental frequency switching of VSI (i.e. electronic commutation of BLDC motor) hence offers reduced switching losses. A voltage follower approach is used for the control of bridgeless Cuk converter operating in 6039

2 discontinuous inductor current mode (DICM) in which a single voltage sensor is required for the sensing of DC-link voltage (Vdc). The proposed drive is designed to operateover a wide range of speed control with improved PQ at AC mains. III. OPERATION OF BRIDGELESS CUK CONVERTER To eliminate the requirement of a DBR such that its conduction losses are reduced, a bridgeless converter Topology is used [23-28]. The converter is designed to Operate in DICM, in which the current in output inductor Lo1 and Lo2 remains discontinuous while the current in input inductors(li1 and Li2) and voltage across the Intermediate capacitors (VC1 and VC2) remain continuous to achieve a PFC at the AC mains. Figs. 2a and b show the operation of the converter for a positive and negative half cycles of the AC supply, respectively. As shown in Fig. 2a, for the positive half cycle of the supply voltage, switch Sw1 is in conduction through Li1 and Dp.The energy ismode I: When switch Sw1 is turned on, an energy is stored in the input inductor Li1 via diode Dp, hence the inductor current ili1 increases as shown in Fig. 2c. Moreover the energy stored in intermediate capacitor C1 is discharged to the DC-link capacitor Cd and the output inductor Lo1. Therefore the current il01 and DC-link voltage Vdc are increased and the voltage across the intermediate capacitor Vc1 reduces in this mode of operation. Transferred through the energy transferring capacitor C1through Lo1 and D1. Similarly, for negative half cycle ofsupply voltage, switch Sw2 is conducting through Li2 anddn as shown in Fig. 2b[29-34]. A common DC-link capacitor Cd isused forboththe positive and negative half cycle ofoperation. The voltage across this DC-link capacitor Cd iscontrolled to achieve the speed control of the BLDC motor. Figs. 2c e show the operation of bridgeless Cuk converter for a complete switching cycle during the positive half cycle of supply voltages. Different modes of operation are described below. Mode II: When switch Sw1 is turned off, the inductor Li1 discharges through intermediate capacitor C1 via diode D1 and Dp. Moreover, inductor Lo1 also transfers its stored energy to DC-link capacitor Cd as shown in Fig. 2d[35-39]. Hence, in this mode of operation, the current in inductors ili1 and ilo1 continues to decrease while the voltage across DC-link capacitor Cd and intermediate capacitor C1 increases. Mode III: Fig. 2e shows the DCM of operation. In this mode, none of the energy is left in the output inductor Lo1, that is, ilo1= 0. The voltage across intermediate capacitor C1 and current in input inductor ili1 increases, while the DC-link capacitor Cd supplies the required energy to the load,hence Vdc reduces in this mode of operation[40-45]. This operation continues till the switch Sw1 is again turned on. Different modes of operation of bridgeless Cuk converter in a complete switching cycle (Figs. 2c e ) for a positive half cycle of supply voltage 6040

3 a Operation for positive half cycle of supply voltage b Operation for negative half cycle of supply voltage c Mode I d Mode II e Mode III particular reference speed of the BLDC motor. This voltage is compared with the sensed DC-link voltage to produce a voltage error signal to be fed in the speed controller. The reference voltage is generated by multiplying the voltage constant (Kv) of the BLDC motor with the reference speed. IV.DESIGN OF BRIDGELESS CUK CONVERTER The Ćuk converter (pronounced Chook; sometimes incorrectly spelled Cuk, Čuk or Cúk) is a type of DC/DC converter that has an output voltage magnitude that is either greater than or less than the input voltage magnitude. It is essentially a boost converter followed by a buck converter with a capacitor to couple the energy. Similar to the buck boost converter with inverting topology, the output voltage of non-isolated Ćuk is typically also inverting, and can be lower or higher than the input. It uses a capacitor as its main energy-storage component, unlike most other types of converters which use an inductor. It is named after Slobodan Ćuk of the California Institute of Technology, who first presented the design. [1] Continuous mode B. Speed controller A voltage error signal is given to the speed controller which is a proportional integral controller for generating a controlled output for the PWM generation stage. At any time instant k, the voltage error signal Ve(k) and controller output Vc(k) is given as (k) = Vdc * (k) (12) Vdc(k) Vc(k) = Vc(k-1) + Kp{Ve(k) Ve(k-1)} + KiVe(k) (13) wherekp and Ki represent the proportional and integral gain constants, respectively. C. PWM generator A fixed frequency, varying duty ratio PWM is generated by a PWM generator by comparing the controlled output of the speed controller with a high frequency sawtooth generator where Sw1 and Sw2 denote the switching signals as 1 and 0 for MOSFET Sw1 and Sw2 to switch on and off, respectively VI. MODELING OF PROPOSED DRIVE SYSTEM Discontinuous mode Like all DC/DC converters Ćuk converters rely on the ability of the inductors in the circuit to provide continuous current, in much the same way a capacitor in a rectifier filter provides continuous voltage. If this inductor is too small or below the "critical inductance", then the current will be discontinuous. This state of operation is usually not studied in much depth, as it is not used beyond a demonstrating of why the minimum inductance is crucial. The minimum inductance is given by: The modeling of a BLDC motor drive consists of a modeling of a BLDC motor, a VSI and an electronic commutation. A. BLDC motor The dynamic modeling of the BLDC motor is governed by following equations [7, 17]. Per phase voltage (Vxn, where x represents a, b or c and n represents neutral) are given as [7] Vxn = Rsis + p x + exn (15) Vxn = Vxo Vno (16) Where fs is the switching frequency. V.CONTROL OF PROPOSED DRIVE SYSTEM The control algorithm of the proposed drive is divided into following different sections. A. Reference voltage generator A reference DC voltage Vdc * is generated by a reference voltage generator which is equivalent to the where p is the time differential operator, Rs represents resistance per phase, ix is the phase current, exn represents back emf, λx represents flux linkages, Vxo and Vno is potential difference of a particular phase x and neutral n with the zero reference potential o which at the mid-point of DC-link respectively as shown in Fig. 3. Electronic Commutation The switching sequence of the VSI is the state of switches for a particular rotor position of the BLDC motor as sensed by the Hall effect sensor. The turn on and turn off condition of the IGBT s is represented as 1 or 0, respectively. The switching sequence of VSI for different positions of the rotor are shown in Table

4 Table 1 Switching states based on Hall effect position sensor signal Hall signals Switching signals Ha Hb Hc S1 S2 S3 S4 S5 S VII. SIMULATED PERFORMANCE OF THE PROPOSED BRIDGELESS CUK CONVERTER-FED BLDC MOTOR DRIVE The performance of the proposed bridgeless Cuk converter-fed BLDC motor drive is evaluated on the basis of performance indices such as supply voltage (Vs), supply current (is), DC-link voltage (Vdc), speed (ω),electromagnetic torque (Te), input inductor current(ili1, ili2), output inductor current (ilo1, ilo2) and intermediate capacitor s voltage (Vc1, Vc2). VIII.CONCLUSION The bridgeless PFC cuk converter fed PMBLDC motor drive system has been proposed for an air conditioning system. The attention devoted to the quality of the currents absorbed from the utility line by electronic equipment is increasing due to several reasons. In fact a low power factor reduces the power available from the utility grid while a high harmonic distortion of the line current causes EMI problems and cross-interferences. From this point of view the standard rectifier employing a diode bridge followed by a filter capacitor gives unacceptable performances. Thus the development of bridgeless cuk converters as interface systems improved the power factor of standard electronic loads. The front end PFC bridgeless cuk converters operating in DICM has been used for dual operation of PFC and DC link voltage control. The proposed drive system has maintained high power factor and improved power quality for a wide range of speed control for varying supply voltages. An efficient topology modification of the combined system with DBR to bridgeless cuk converter is presented in this project provide more convenient operation and improve the system efficiency. REFERENCES 1. Nimal, R.J.G.R., Hussain, J.H., Effect of deep cryogenic treatment on EN24 steel, Mathematics, V-116, I-17, PP , Parameswari, D., Khanaa, V., Deploying lamport clocks and linked lists, International Journal of Pharmacy and Technology, V-8, I- 3, PP , Parameswari, D., Khanaa, V., Case for massive multiplayer online role-playing games, International Journal of Pharmacy and Technology, V-8, I-3, PP , Parameswari, D., Khanaa, V., Deconstructing model checking with hueddot, International Journal of Pharmacy and Technology, V-8, I- 3, PP , Parameswari, D., Khanaa, V., The effect of self-learning epistemologies on theory, International Journal of Pharmacy and Technology, V-8, I-3, PP , Pavithra, J., Peter, M., GowthamAashirwad, K., A study on business process in IT and systems through extranet, International Journal of Pure and Applied Mathematics, V-116, I-19, PP , Pavithra, J., Ramamoorthy, R., Satyapira Das, S., A report on evaluating the effectiveness of working capital management in googolsoft technologies, Chennai, International Journal of Pure and Applied Mathematics, V-116, I-14, PP ,

5 8. Pavithra, J., Thooyamani, K.P., A cram on consumer behaviour on Mahindra two wheelers in Chennai, International Journal of Pure and Applied Mathematics, V-116, I-18, PP-55-57, Pavithra, J., Thooyamani, K.P., Dkhar, K., A study on the air freight customer satisfaction, Mathematics, V-116, I-14, PP , Pavithra, J., Thooyamani, K.P., Dkhar, K., A study on the working capital management of TVS credit services limited, International Journal of Pure and Applied Mathematics, V- 116, I-14, PP , Pavithra, J., Thooyamani, K.P., Dkhar, K., A study on the analysis of financial performance with reference to Jeppiaar Cements Pvt Ltd, Mathematics, V-116, I-14, PP , Peter, M., Dayakar, P., Gupta, C., A study on employee motivation at Banalari World Cars Pvt Ltd Shillong, International Journal of Pure and Applied Mathematics, V-116, I-18, PP , Peter, M., Kausalya, R., A study on capital budgeting with reference to signware technologies, International Journal of Pure and Applied Mathematics, V-116, I-18, PP-71-74, Peter, M., Kausalya, R., Akash, R., A study on career development with reference to premheerasurgicals, International Journal of Pure and Applied Mathematics, V-116, I-14, PP , Peter, M., Kausalya, R., Mohanta, S., A study on awareness about the cost reduction and elimination of waste among employees in life line multispeciality hospital, International Journal of Pure and Applied Mathematics, V- 116, I-14, PP , Peter, M., Srinivasan, V., Vignesh, A., A study on working capital management at deccan Finance Pvt Limited Chennai, Mathematics, V-116, I-14, PP , Peter, M., Thooyamani, K.P., Srinivasan, V., A study on performance of the commodity market based on technicalanalysis, Mathematics, V-116, I-18, PP , Philomina, S., Karthik, B., Wi-Fi energy meter implementation using embedded linux in ARM 9, Middle - East Journal of Scientific Research, V-20, I-12, PP , Philomina, S., Subbulakshmi, K., Efficient wireless message transfer system, Mathematics, V-116, I-20, PP , Philomina, S., Subbulakshmi, K., Ignition system for vechiles on the basis of GSM, Mathematics, V-116, I-20, PP , Philomina, S., Subbulakshmi, K., Avoidance of fire accident by wireless sensor network, Mathematics, V-116, I-20, PP , Pothumani, S., Anuradha, C., Monitoring android mobiles in an industry, International Journal of Pure and Applied Mathematics, V- 116, I-20, PP , Pothumani, S., Anuradha, C., Decoy method on various environments - A survey, Mathematics, V-116, I-10, PP , Pothumani, S., Anuradha, C., Priya, N., Study on apple icloud, International Journal of Pure and Applied Mathematics, V-116, I-8 Special Issue, PP , Pothumani, S., Hameed Hussain, J., A novel economic framework for cloud and grid computing, International Journal of Pure and Applied Mathematics, V-116, I-13 Special Issue, PP-5-8, Pothumani, S., Hameed Hussain, J., A novel method to manage network requirements, Mathematics, V-116, I-13, PP-9-15, Pradeep, R., Vikram, C.J., Naveenchandra, P., Experimental evaluation and finite element analysis of composite leaf spring for automotive vehicle, Middle - East Journal of Scientific Research, V-12, I-12, PP ,

6 28. Prakash, S., Jayalakshmi, V., Power quality improvement using matrix converter, Mathematics, V-116, I-19, PP , Prakash, S., Jayalakshmi, V., Power quality analysis & power system study in high voltage systems, International Journal of Pure and Applied Mathematics, V-116, I-19, PP-47-52, Prakash, S., Sherine, S., Control of BLDC motor powered electric vehicle using indirect vector control and sliding mode observer, Mathematics, V-116, I-19, PP , Prakesh, S., Sherine, S., Forecasting methodologies of solar resource and PV power for smart grid energy management, Mathematics, V-116, I-18, PP , Prasanna, D., Arulselvi, S., Decoupling smalltalk from rpcs in access points, Mathematics, V-116, I-16, PP- 1-4, Prasanna, D., Arulselvi, S., Exploring gigabit switches and journaling file systems, Mathematics, V-116, I-16, PP , Prasanna, D., Arulselvi, S., Collaborative configurations for wireless sensor networks systems, International Journal of Pure and Applied Mathematics, V-116, I-15 Special Issue, PP , Priya, N., Anuradha, C., Kavitha, R., Li-Fi science transmission of knowledge by way of light, International Journal of Pure and Applied Mathematics, V-116, I-9 Special Issue, PP , Priya, N., Pothumani, S., Kavitha, R., Merging of e-commerce and e-market-a novel approach, International Journal of Pure and Applied Mathematics, V-116, I-9 Special Issue, PP , Raj, R.M., Karthik, B., Effective demining based on statistical modeling for detecting thermal infrared, International Journal of Pure and Applied Mathematics, V-116, I-20 Special Issue, PP , Raj, R.M., Karthik, B., Energy sag mitigation for chopper, International Journal of Pure and Applied Mathematics, V-116, I-20 Special Issue, PP , Raj, R.M., Karthik, B., Efficient survey in CDMA system on the basis of error revealing, Mathematics, V-116, I-20, PP , Rajasulochana, P., Krishnamoorthy, P., Ramesh Babu, P., Datta, R., Innovative business modeling towards sustainable E- Health applications, International Journal of Pharmacy and Technology, V-4, I-4, PP , Rama, A., Nalini, C., Shanthi, E., An iris based authentication system by eye localization, International Journal of Pharmacy and Technology, V-8, I-4, PP , Rama, A., Nalini, C., Shanthi, E., Effective collaborative target tracking in wireless sensor networks, International Journal of Pharmacy and Technology, V-8, I-4, PP , Ramamoorthy, R., Kanagasabai, V., Irshad Khan, S., Budget and budgetary control, Mathematics, V-116, I-20, PP , Ramamoorthy, R., Kanagasabai, V., Jivandan, S., A study on training and development process at Vantec Logistics India Pvt Ltd, Mathematics, V-116, I-14, PP , Pradeep, R., Vikram, C.J., Naveenchandran, P., Experimental evaluation and finite element analysis of composite leaf spring for automotive vehicle, Middle - East Journal of Scientific Research, V-17, I-12, PP ,

7 6045

8 6046