Analytical Method of a Torque Ripple Calculation for Two-Phase IM Supplied by Three-Leg SPWM Inverter
Pavel Záskalický Department of Electrotechnics and Mechatronics Technical University (TUKE) Košice, Slovak Republic pavel.zaskalicky@tuke.sk
Branislav Dobrucký Department of Mechatronics and Electronics
, Slovak Republic dobrucky@fel.uniza.sk
Abstract—The contribution deals with steady state estimation of a electromagnetic torque ripples and a current waveform of a two-phase induction motor, which is supplied by an three-leg IGBT bridge connected inverter. The inverter’s output voltage is controlled by a modified sinusoidal SPWM of the input DC voltage. The complex Fourier series analysis of the inverter’s output voltage was made, to obtain a spectrum of the harmonic supply voltage. The different voltage harmonics have been applied to the two-phase induction machine model to obtain electromagnetic torque and supply current waveforms for various operation states.
Keywords—two-phase induction motor, torque ripple estimation, bridge invertor, Fourier series, sinusoidal PWM control I. INTRODUCTION The electrical low-power drives which are supplied by a single phase voltage used in different industrial and domestic devices are presently increasingly deployed by two-phase motors. A two-phase motor by their characteristics no differs from the three-phase ones. Their advantage is simpler winding layout, which is of great importance for automated motor production [1]-[2].
The two-phase motors are at present manufactured as either squirrel cage induction or permanents magnets synchronous motors. They are very often deployed as a pumps drives in a washing machines and dishwashers, but also in a circulating pumps for central domestic heating. A permanent magnet in this case is water and lye resistant, which allows making a pump with an absolute waterproof.
The stator winding can be configured in either a serial or parallel two-phase system. Normally, the winding are identical. The windings which form one phase are connected to induce opposite magnetic polarity. II. MATHEMATICAL MODEL OF A SUPPLY CONVERTER To build a mathematical model of a two-phase inverter’s a complex Fourier series approach was used. In the model we consider following idealized conditions: Power switch can handle unlimited current and blocks unlimited voltage.
The voltage drop and leakage current across the switches are zero. The switches are turned on and off with no rise and fall times. Sufficiently good size capacity of the inverter’s input voltage capacitors, to can suppose constant converter input DC voltage for any load.
These assumptions help us simpler to analyze a motor power supply circuit and help us to build a mathematical model of invertor at steady state. Fig. 1 shows a two-phase convertor circuit layout, supplied by a single-phase network. The inverter of the converter consists of three transistors branches (b-, a-, c- ones). The first branch (b) is common branch for both other phases. Contrary to common analysis method the reference voltage potential is not created by centre tap of DC link as [4] but with its negative potential for Fourier series analysis used in the next part of paper.
Fig. 1. Supply convertor circuit layout.
978-1-4799-4749-2/14/$31.00 ©2014 IEEE
2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion
731
Analytical Method of a Torque Ripple Calculation for Two-Phase IM Supplied by Three-Leg SPWM Inverter
Pavel Záskalický Department of Electrotechnics and Mechatronics Technical University (TUKE) Košice, Slovak Republic pavel.zaskalicky@tuke.sk
Branislav Dobrucký Department of Mechatronics and Electronics
, Slovak Republic dobrucky@fel.uniza.sk
Abstract—The contribution deals with steady state estimation of a electromagnetic torque ripples and a current waveform of a two-phase induction motor, which is supplied by an three-leg IGBT bridge connected inverter. The inverter’s output voltage is controlled by a modified sinusoidal SPWM of the input DC voltage. The complex Fourier series analysis of the inverter’s output voltage was made, to obtain a spectrum of the harmonic supply voltage. The different voltage harmonics have been applied to the two-phase induction machine model to obtain electromagnetic torque and supply current waveforms for various operation states.
Keywords—two-phase induction motor, torque ripple estimation, bridge invertor, Fourier series, sinusoidal PWM control I. INTRODUCTION The electrical low-power drives which are supplied by a single phase voltage used in different industrial and domestic devices are presently increasingly deployed by two-phase motors. A two-phase motor by their characteristics no differs from the three-phase ones. Their advantage is simpler winding layout, which is of great importance for automated motor production [1]-[2].
The two-phase motors are at present manufactured as either squirrel cage induction or permanents magnets synchronous motors. They are very often deployed as a pumps drives in a washing machines and dishwashers, but also in a circulating pumps for central domestic heating. A permanent magnet in this case is water and lye resistant, which allows making a pump with an absolute waterproof.
The stator winding can be configured in either a serial or parallel two-phase system. Normally, the winding are identical. The windings which form one phase are connected to induce opposite magnetic polarity. II. MATHEMATICAL MODEL OF A SUPPLY CONVERTER To build a mathematical model of a two-phase inverter’s a complex Fourier series approach was used. In the model we consider following idealized conditions: Power switch can handle unlimited current and blocks unlimited voltage.
The voltage drop and leakage current across the switches are zero. The switches are turned on and off with no rise and fall times. Sufficiently good size capacity of the inverter’s input voltage capacitors, to can suppose constant converter input DC voltage for any load.
These assumptions help us simpler to analyze a motor power supply circuit and help us to build a mathematical model of invertor at steady state. Fig. 1 shows a two-phase convertor circuit layout, supplied by a single-phase network. The inverter of the converter consists of three transistors branches (b-, a-, c- ones). The first branch (b) is common branch for both other phases. Contrary to common analysis method the reference voltage potential is not created by centre tap of DC link as [4] but with its negative potential for Fourier series analysis used in the next part of paper.
Fig. 1. Supply convertor circuit layout.
978-1-4799-4749-2/14/$31.00 ©2014 IEEE
2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion
731
การแปล กรุณารอสักครู่..
