Experimental Evaluation of Solar Photovoltaic based PMBLDCM Drive for Low Power Application

Experimental Evaluation of Solar Photovoltaic based PMBLDCM Drive for Low Power Application

Munesh Kumar Singh

E.I.E. Department SLIET Longowal

District-Sangrur, 148106, India

Sachin Singh

E.I.E. Department SLIET Longowal

District-Sangrur, 148106, India

Sanjeev Singh

E.I.E. Department SLIET Longowal

District-Sangrur, 148106, India

Abstract This paper deals with the feasibility study of solar photovoltaic system based Permanent magnet brushless DC (PMBLDC) motor drive coupled to a low power application. The simulation model of complete drive is developed in MATLAB-SIMULINK and simulated response of proposed drive is obtained under various operating conditions. The hardware prototype setup is also developed in the lab for the validation of the simulation results. The obtained Simulation and hardware results are presented to demonstrate the feasibility of a SPV system based PMBLDCM drive.

Keywords PV Array; VSI; PMBLDCM Drive

1. INTRODUCTION

   Permanent Magnet Brushless motor is mostly used in the low power applications. It has the high efficiency rugged construction and easy of control to be used for speed control applications. Three- phase voltage source inverter (VSI) or current source inverter (CSI) is required to control the PMBLDC Motor using its rotor position information. Hall sensors are used for the rotor position sensing. These sensors increase the size, cost and complexity of PMBLDCM drives.

   trying to increase its efficiency, reliability and ease of handling [6-7].

   This paper presents a standalone solar PV system based PMBLDCM drives for low power applications. The PV module supplied to VSI for driving the PMBLDC motor. The proposed system includes PV module, three phase VSI, and PMBLDCM drive. The experimental setup is implemented for the practical analysis of proposed system.

2. PROPOSED SYSTEM CONFIGURATION AND WORKING OF OPERATION

   Fig. 1 shows the proposed system consisting of a SPV array, VSI and PMBLDCM drive. The Solar radiation strikes on the surface of PV array and it generate DC supply at output terminal of PV system. A three phase VSI is required to operate the PMBLDCM drive.

   VSI

   Recently, PMBLDCM drives are used in electric vehicles

   (EVs) and Hybrid electric vehicles (HEVs) due to the environmental concern vehicular emissions [1-5].

   S1 S3 S5

   PMBLDC MOTOR

   At present, we have the crises of fossil fuel, conventional resources such as coal, Petroleum and Natural gas. Due to the

   S2 S4 S6

   pollution problem, Green house effect and CO2 emission, humankind is trying to utilize the non conventional resources in an appropriate way. Advanced technologies are increasing for utilization of renewable energy in different applications.

   Amongst various renewable energy sources, Solar Energy plays an important role in recent scenario. Because of the free availability of solar energy, it can be use for different

   PV Array

   Hall signals

   Hall signals

   Electronic commutator

   applications like water heater, solar cooker, solar water pump, solar street light etc. For the electricity extraction, solar photovoltaic systems consisting of semiconductor cells, which convert the solar energy into electricity, are used in different applications. The output of SPV system depends upon the solar radiation and temperature. Maximum power point tracking (MPPT) is required for the maximum energy extraction from SPV systems. As a thrust area, researchers are

   Fig.1: Solar PV based PMBLDCM drive

   The Hall sensor is required for sensing the rotor position and feed it to electronic commutator. Electronic commutator generates the six gate signal for each switch of VSI so that PMBLDCM drive is operated as desired for Low Power application.

   1. Modelling of PV Module

      The equivalent circuit of a single PV cell is given in fig. 2. It consist a current source, a diode, a shunt resistance and a series resistance [7].

      Rs

      = (/2)	for 1 = 1, 2 = 0	(5)
      = (/2)	for 2 = 1, 1 = 0	(6)
      = 0	for 1 = 0, 2 = 0	(7)
      =		(8)

      = (/2)	for 1 = 1, 2 = 0	(5)
      = (/2)	for 2 = 1, 1 = 0	(6)
      = 0	for 1 = 0, 2 = 0	(7)
      =		(8)

      L O

      in the inner loop of speed control and rotor position signal acquired using Hall Effect sensors.

      The VSI Bridge feeding PMBLDCM uses insulated gate bipolar transistors (IGBTs) to reduce the switching stress.

      Fig.3 shows the equivalent circuit of VSI Fed PMBLDCM Drive. The output of VSI for phase a is given as

      Iph Io Rp

      Ipv A

      D

      Fig.2: PV Cell circuit model

      Iph is the Photon current, Rp and Rs are the shunt and

      Where Vao, Vbo, Vco and Vno are the 3-phase voltage and neutral point dc link voltages.

      series resistance respectively. The value of Rp should very high and Rs should be very low, hence they neglected to simplify the analysis. The PV module is the combinations of PV cells connected in series and parallel. For high voltage,

      Vdc

      VSI

      S1 S3 S5

      PMBLDC Motor

      R

      LVan

      Vdc/2

      The modules should be connect in series and high current, the

      ean

      Vno

      connection should be in parallel.

      Module Parameters and mathematical equations the PV

      S2 S4 S6

      Lebn n

      R

      ecnL R

      o

      Vdc/2

      modules are given below [8].

      Table-1: PV Parameters Definition

      Vpv Output voltage of a PV module (V) Ipv Output current of a PV module (A) Tr Reference temperature (298 K)

      T Module operating temperature in Kelvin Iph Light generated current in a PV module (A) Io PV module saturation current (A)

      A /B An ideality factor (1.6)

      K Boltzmann constant (1.3805 × 10-23 J/K) q Charge on electron(1.6 × 10-19 C)

      Rs Series resistance of a PV module Rp Parallel resistance of PV module

      Iscr PV module short-circuit current at 25oC and 1000W/m2 Ki short-circuit current temperature co-efficient at Solar

      radiation 1000W/m2

      S PV module illumination(W/m2) = 1000W/m2 Ego Band gap for silicon (1.1 eV)

      Ns number of cells connected in series Np number of cells connected in Parallel

      Module photo-current:

      Vbn Vcn

      Fig.3: Equivalent circuit of VSI fed PMBLDCM Drive

      The PMBLDC motor is modeled in the form of a set of differential equations [9] given as

      = + + (9)

      = + + (10)

      = + + (11)

      In above equations, p represents the differential operator, ia, ib, ic are currents, a, b, c are the flux linkages and ean, ebn, ecn are phase to neutral back emf of PMBLDCM, in respective phases, Ra, Rb, Rc are resistances of motor windings/phase.

      The Torque developed in PMBLDC motor is given as

      = [

      + ( 298)]

      (1)

      = ( + + )/ (12)

      1000

      where r is speed of motor in rad/sec.

      Module reverse saturation current (Irs):

      =

      =

      [exp( )1]

      The Module Saturation current Io:

      (2)

3. SIMULATION AND HARDWARE IMPLEMENTATION

   1. Simulation Model of Proposed System

      The SIMULINK / MALAB is a basic tool for

      = [/]3exp( { 1 1}) (3)

      understanding the behavior of the system. The SIMULINK

      Tr T

      models developed in MATLAB using the mathematical

      The output PV module current Ipv:

      = [ {

   2. Modelling of PMBLDCM Drive

   +} 1] (4)

   equations of solar PV system to generate the DC supply. The DC link capacitor is connected to the output of the PV system terminal to maintain the voltage level. The 3 phase VSI is used to convert DC to AC for operating the drive using Electronic commutation. The parameters of motor are same as the available motor in Hardware. Fig.4 shows SIMULINK

   The PMBLDCM drives in low power applications are mostly supplied from a DC source. The commutation of PMBLDCM is accomplished electronically by a three phase voltage source inverter (VSI) based on current control scheme

   model of proposed system.

   B. Hardware Implementation of Proposed System

   The hardware setup is implemented using the PV modules; IGBTs based Voltage source inverter (VSI) and proposed

   drive. The PV modules are used with following parameters of single module is shown in Table2.

   Fig.4: SIMULINK model of proposed system

   Table-2: Key Specification of Single PV Module Electrical Characteristics ELDORA 40 Nominal Power 40 W

   Optimum Operating Voltage 21.9 V Optimum Operating current 2.45 A Open circuit voltage Voc 17.4 V

   Short circuit current Isc 2.3 A

   Temperature coefficient 0.005A/o C

   Two modules connected in parallel for operating the proposed PMBLDCM drive. The output of the PV system is approximate 17 volts and current is less than 1 A. DC link capacitor is used for maintain the voltage level. The proposed drive is operated by the Photovoltaic system. Fig. 5 shows the hardware implementation using PV system and dSPACE signal processor.

4. PERFORMANCE EVALUATION OF PROPOSED SYSTEM

   This section deals with the results and discussion on the proposed drive. The Simulation modeled proposed system discussed in III. The Simulation results are shown in Fig. 6.

   Fig.5: Hardware implementation of proposed drive

   Fig.6: Simulation results of Proposed System

   The details of the motor parameter mentioned in appendix. The output of the PV system around 17V, 1A and 470 f DC link capacitor connected to the VSI. The Proposed PMBLDCM drive has constant torque 0.3 Nm and it give the speed of 250 rpm which can be used for the low power application.

   The Proposed system Hardware is operated for validation the simulation results. The parameters of motor are given in appendix. The dSPACE is used for development of the hardware prototype of proposed PMBLDCM drive. Opto- isolation is provided between processor and switches used in VSI and PFC converter for protection. A filtering, isolation and driver circuit is also required for Hall Effect sensor position. Test results of proposed system are discussed in the following section.

   In Hardware Implementation, ELDORA40 PV modules are used for the analysis study and validation of the Proposed PMBLDCM drive. In Fig. 7(a) and 7(b), the speed and stator current are shown and their waveform approximate same to the simulated results.

   Fig.7 (a): Performance of Solar PV fed PMBLDCM Drive

   Fig.7 (b): Enlarge view of Fig. 7(a)

5. CONCLUSION

A Solar Photovoltaic based PMBLDCM Drive has been evaluated for the low power applications. The simulation results have been presented for demonstration of proposed concepts and its validation has been carried out using the

Hardware prototype. Solar PV based system is simple, reliable, conserve energy and needs no maintenance.

APPENDIX

Rated Power: 1.1 KW, rated speed: 4600 rpm, rated current 2.2 A, rated torque: 2.2 Nm, number of pole pairs:2, input DC voltage: 310 Vdc, phase to phase resistance: 3.07 , phase to phase inductance: 6.57 mH, maximum current: 10.3 A, maximum torque: 6.6 Nm, Voltage constant (Kb): 0.49.

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