Commissioning of A VFD Controller For The Performance Analysis of A 2 Pole Induction Motor

Transcription

1 Commissioning of A VFD Controller For The Performance Analysis of A 2 Pole Induction Motor Ram Singh 1, Navdeep Choudhary 2, Alok Mishra 3, Ketandeep Jamwal 4, Mukund Madhav 5 1 A.P, Electrical Engineering, BHSBIET Lehragaga 1 HOD & A.P of. Electronics & Communication Engineering, BHBIET Lehragaga 2 Design Engineer in TATA Power Corp. Mumbai B-tech 4 th year, Electronics & Communication Engineering, BHBIET Lehragaga 4 B-tech 4 th year, Electronics & Communication Engineering, BHBIET Lehragaga 5 ABSTRACT In this paper performance of the induction motor under various load condition have been presented. The motor is controlled using a sensorless VFD control drive. The specification of the motor tested and controller drive is given in the section IV. Section I and II gives a brief summary of a VFD controller and induction motor. Later in section III the commissioning of the control drive has been presented. Various torque speed and torque current characteristics have been presented in section IV for various load condition. The tested motor is then used in an electromechanical drive for a launcher. 1. INTRODUCTION VARIABLE FREQUENCY DRIVE The variable frequency drive controller is a solid state power electronics conversion system consisting of three distinct sub-systems: a rectifier bridge converter, a direct current (DC) link, and an inverter. Voltage-source inverter (VSI) drives (see 'Generic topologies' sub-section below) are by far the most common type of drives. Most drives are AC-AC drives in that they convert AC line input to AC inverter output. However, in some applications such as common DC bus or solar applications, drives are configured as DC-AC drives. The most basic rectifier converter for the VSI drive is configured as a three-phase, six-pulse, full-wave diode bridge. Figure 1 block diagram of the induction motor with VFD controller In a VSI drive, the DC link consists of a capacitor which smooths out the converter's DC output ripple and provides a stiff input to the inverter. This filtered DC voltage is converted to quasi-sinusoidal AC voltage output using the inverter's active switching elements. VSI drives provide higher power factor and lower harmonic distortion than phasecontrolled current-source inverter (CSI) and load-commutated inverter (LCI) drives. The drive controller can also be configured as a phase converter having singlephase converter input and three-phase inverter output.[7] Controllers have been improved to exploit quantum solid state power switching device improvements in terms of voltage and current ratings and switching frequency over the past six decades. Introduced in the 1983,[8] the insulated-gate bipolar transistor (IGBT) has in the past two decades come to dominate VFDs as an inverter switching device.[9][10][11] In variable-torque applications suited for Volts per Hertz (V/Hz) drive control, AC motor characteristics require that the voltage magnitude of the inverter's output to the motor be adjusted to match the required load torque in a linear V/Hz relationship. Some V/Hz control drives can also operate in quadratic V/Hz mode or can even be programmed to suit special multi-point V/Hz paths.[12][13] The two other drive control platforms, vector control and direct torque control Volume 1, Issue 3, November 2012 Page 62

2 (DTC), adjust the motor voltage magnitude, angle from reference and frequency[14] such as to precisely control the motor's magnetic flux and mechanical torque. Although space vector pulse-width modulation (SVPWM) is becoming increasingly popular,[15] sinusoidal PWM (SPWM) is the most straightforward method used to vary drives' motor voltage (or current) and frequency. With SPWM control (see Fig. 1), quasi-sinusoidal, variable-pulse-width output is constructed from intersections of a saw-toothed carrier frequency signal with a modulating sinusoidal signal which is variable in operating frequency as well as in voltage (or current).[16][9][17] Operation of the motors above rated nameplate speed (base speed) is possible, but is limited to conditions that do not require more power than the nameplate rating of the motor. This is sometimes called "field weakening" and, for AC motors, means operating at less than rated V/Hz. OPERATOR INTERFACE The operator interface provides a means for an operator to start and stop the motor and adjust the operating speed. Additional operator control functions might include reversing, and switching between manual speed adjustment and automatic control from an external process control signal. The operator interface often includes an alphanumeric display and/or indication lights and meters to provide information about the operation. 2. INDUCTION MOTOR Three-phase induction motors are the most common and frequently encountered machines in industry simple design, rugged, low-price, easy maintenance wide range of power ratings: fractional horsepower to 10 MW run essentially as constant speed from no-load to full load Its speed depends on the frequency of the power source not easy to have variable speed control requires a variable-frequency power-electronic drive for optimal speed control Figure 2 a view of induction motor An induction motor has two main parts: 1. a stationary stator consisting of a steel frame that supports a hollow, cylindrical core core, constructed from stacked laminations, having a number of evenly spaced slots, providing the space for the stator winding 2. a revolving rotor composed of punched laminations, stacked to create a series of rotor slots, providing space for the rotor winding one of two types of rotor windings conventional 3-phase windings made of insulated wire (wound-rotor)» similar to the winding on the stator aluminum bus bars shorted together at the ends by two aluminum rings, forming a squirrel-cage shaped circuit (squirrel-cage). 3. STARTER DRIVE /COMMISIONING SOFTWARE The STARTER drive/commissioning software supports the commissioning and maintenance of SINAMICS G120 converters. It provides operator guidance designed to simplify and speed up commissioning, combined with comprehensive, user-friendly functions for the relevant drive solution. Volume 1, Issue 3, November 2012 Page 63

3 Figure 4 view of Siemens companies vfd drive 4. PERFORMANCE ANALYSIS OF THE INDUCTION MOTOR TECHNICAL SPECIFICATIONS OF MOTOR TESTED Table.1 technical specification of the motor drive used Sl no Factors Ratings 01 Power 3.7 kw 02 Full load current 7.1 a 03 Speed 2900 rpm 04 Voltage 415 v, 3 phase 05 Power factor Serial no. Nosdf/ TECHNICAL SPECIFICATION OF DRIVE USED Table 2 technical specification of the control drive used SL NO. FACTORS DETAILS 01 COMPANY SIEMENS 02 POWER 4 KW 03 I/P VOLTAGE V 04 I/P CURRENT 13.4 A 05 FREQUENCY 50 HZ 06 MODEL NO. 6SL OBE24 - OUAO TEST SET UP The following figure shows the test set for the evaluation of the performance of the induction motor in the motor testing cell. It include the mounting bench over which both the motor and dynamometer are horizontally coupled. The three phase star connected connections of the motor input are connected to the three phase output connections of the drive which generates the PWM signals.the three phase input connections to the drive are made from the three phase 440 v main supply board. The earthing facility is provided for both motor and drive. Initially the dynamometer is not loaded but then also the motor rotate with a torque at no laod due to the coupling with the dynamometer. The cooling pipes are connected to the dynamometers for cooling purpose during the test. Figure 4 view of test set up for the induction motor tested Volume 1, Issue 3, November 2012 Page 64

4 COMMISSIONING OF THE CONTROL DRIVE The drive was commissioned as per the specification of the motor under test using the following steps: Start the drive and press P>displays r000> change it to P0010 using increase button. Press P>displays In000>change to In001. Press P>displays P0010>change to P0300>displayIn000>change to 1(to select motor type) Press P>display P0300>change to P0304>press P>displays 0.0>change it to the rated voltage of the motor (415 v). Press P>display P0304>change to P0305>press P>display 0.0 >change it to motor rated current (7.1 A) Press P>display P0305>change it to P0307>press P >display 0.0?change it to motor rated power (3.7 kw) Similarly set the other factors of the motors in the drive using the following table: Table 3 parameters used for the quick commissioning of the drive Table 4 commissioning parameters of the vfd drive used After commissioning is done and the motor starts rotating the parameters which can be read and noted from the drive display are given in the table below along with their respective parameters: Volume 1, Issue 3, November 2012 Page 65

5 Chart.1 readable parameters of the vfd drive used MOTOR PERFORMANCE AT NO LOAD Table 5 observation table for no-load test of the induction motor Sr Motor Drive Dynomometer No. Time Speed Torque I/P Vtg. Current Freq. Power Temp. I/P VoltageCurrent Freq. dc Voltage Speed Power Torque (N-m) (Volts) (Amps) (Hz) (kw) (Deg. C) (Volts) (Amps) (Hz) (Volts) (kw) (N-m) 1 14: : : : : : : : : : Figure 5 torques speed plot obtained from the no load test s observations Figure 6 torque current plot obtained from the no load test s observations MOTOR PERFORMANCE UNDER FULL LOAD Table 6 observation table for full-load test of the induction motor tested Sr Motor Drive Dynomometer No. Time Speed Torque I/P Vtg. Current Freq. Power Temp. I/P VoltagCurrent Freq. dc Voltage Speed Power Torque (N-m) (Volts) (Amps) (Hz) (kw) (Deg. C) (Volts) (Amps) (Hz) (Volts) (kw) (N-m) 1 15: : : : : : : : : : Volume 1, Issue 3, November 2012 Page 66

6 Figure 7 toque v/s speed plot of the tested induction motor under full load test Figure 8 toque v/s current plot of the tested induction motor under full load test MOTOR PERFORMACE UNDER 110% OVER LOAD Table 7 observation table for the over-load test of the tested induction motor Sr Motor Drive Dynomometer No. Time Speed Torque I/P Vtg. Current Freq. Power Temp. I/P VoltagCurrent Freq. dc Voltage Speed Power Torque (N-m) (Volts) (Amps) (Hz) (kw) (Deg. C) (Volts) (Amps) (Hz) (Volts) (kw) (N-m) 1 16: : : : : : : : : : Figure 9 toque v/s speed plot of the tested induction of the tested induction motor Figure 10 toque v/s current plot of the tested induction motor under over-load test 5. CONCLUSSIONS The following conclusions were made after undergoing the above tests for the induction motor of siemence company : The characteristic performance of the induction motor under no-load test was satisfactory as compared with The characteristic performance of the induction motor under full-load test was satisfactory as compared with The characteristic performance of the induction motor under over-load test was satisfactory as compared with The characteristic performance of the induction motor under endurance test was satisfactory as compared with The motor is suitable to be used in the required area of the launcher. The drive is having satisfied performance with easier commissioning system and cooling systems. Volume 1, Issue 3, November 2012 Page 67

7 REFRENCES [1] A. E. Fitzgerald, et al., "Electric Machinery," 5th Ed., McGraw-Hill, [2] IEEE Standard , "IEEE Standard Test Procedure for Polyphase Induction Motors and Generators," Institute of Electrical and Electronics Engineers, Inc. [3] G. R. Slemon,"Modelling Induction Machines for Electric Drives," IEEE Trans. on Industry Applications, Vol. 25, No. 6, pp , Nov [4] D. W. Novotney, et al.(editor), "Introduction to Field Orientation and High Performance AC Drives," IEEE IAS Tutorial Course, [5] A. M. Trzynadlowski, The Field Orientation Principle in Control of Induction Motors, Kluwer Academic Publishers [6] J. Holtz, "Pulse Width Modulation for Electronic Power Conversion," Proceedings of IEEE, Vol.82, No.8, p , Aug [7] R. DeDonker and D. W. Novotney, The Universal Field Oriented Controller, IEEE Trans. Industry Applications, Vol. 30, No.1, pp , Jan Volume 1, Issue 3, November 2012 Page 68