A quasi resonant pulse width modulation(PWM) inverter is used in a solar power system to convert the solar panel and battery charger's direct current(DC) output to alternating current(AC).Although much has been...A quasi resonant pulse width modulation(PWM) inverter is used in a solar power system to convert the solar panel and battery charger's direct current(DC) output to alternating current(AC).Although much has been published about DC to AC PWM inverters,none of the previous work has shown modeling and simulation results for DC to AC inverters.In this study,we suggest a new topology for a quasi resonant PWM inverter.Experimental results are also presented.展开更多
Capacitor voltage imbalance is a significant problem for three-level inverters.Due to the mid-point modulation of these inverter topologies,the neutral point potential moves up or down depending on the neutral point c...Capacitor voltage imbalance is a significant problem for three-level inverters.Due to the mid-point modulation of these inverter topologies,the neutral point potential moves up or down depending on the neutral point current direction creating imbalanced voltages among the two capacitors.This imbalanced capacitor voltage causes imbalanced voltage stress among the semiconductor devices and causes increase output voltage and current harmonics.This paper introduces a modified voltage balancing strategy using two-level space vector modulation.By decomposing the three-level space vector diagram into two-level space vector diagram and redistributing the dwell times of the two-level zero space vectors,the modified voltage balancing method ensures minimal NP voltage ripple.Compared to the commonly used NP voltage control method(using 3L SVM[9]),the proposed modified NP voltage control method offers a slightly higher neutral-point voltage ripple and output voltage harmonics but,it has much lower switching loss,code size and execution time.展开更多
In this paper, a new inverter topology dedicated to isolated or grid-connected PV systems is proposed. This inverter is based on the structures of a stacked multi-cell converter (SMC) and an H-bridge. This new topolog...In this paper, a new inverter topology dedicated to isolated or grid-connected PV systems is proposed. This inverter is based on the structures of a stacked multi-cell converter (SMC) and an H-bridge. This new topology has allowed the voltage stresses of the converter to be distributed among several switching cells. Secondly, divide the input voltage into several fractions to reduce the number of power semiconductors to be switched. In this contribution, the general topology of this micro-inverter has been described and the simulation tests developed to validate its operation have been presented. Finally, we discussed the simulation results, the efficiency of this topology and the feasibility of its use in a grid-connected photovoltaic production system.展开更多
The full bridge zero voltage zero current switching ( FB-ZVZCS ) , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circu...The full bridge zero voltage zero current switching ( FB-ZVZCS ) , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.展开更多
In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter ...In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter are added to input circuit of the inverter.Single-phrase full-bridge inverter performs the function of converting direct current into alternating current(DC/AC).In the control circuit,single chip micyoco(SCM)AT89C2051 is used for main control chip to accomplish the hardware design of the control system.A given value of output frequency of the inverter is input in the way of coding.According to the output frequency code which is read,SCM AT89C2051 defined harmonic elimination PWM control data which will be selected.Through internal timing control,the switches are switched under this provision of PWM control data.Then the driving signals of the switches in the inverter are output from I/O of SCM AT89C2051 to realize harmonic elimination PWM control.The results show that adding Newton homotopic algorithm of harmonic elimination PWM control to corresponding software of the control system can make the quality of output voltage of the inverter higher and it will have broad application prospects.展开更多
The single-phase three-level voltage source inverter based on wavelet modulation(WM) is proposed.The WM technique is based on constructing a nondyadic-type multi-resolution analysis(MRA),which supports sampling contin...The single-phase three-level voltage source inverter based on wavelet modulation(WM) is proposed.The WM technique is based on constructing a nondyadic-type multi-resolution analysis(MRA),which supports sampling continuous-time sinusoidal signals in a nonuniform recurrent manner,and then reconstructing it by using inverter switching actions. In order to further improve the output voltage waveform and reduce harmonic distortion,the wavelet modulation is used to three-level inverter. The high magnitude of fundamental component and significantly reduced harmonic contents of the inverter output voltage can be achieved by using WM in the single-phase three-level voltage source inverter. Furthermore,the WM algorithm is implemented by using only one element government(EV) in DSP. The simulated and experimental results prove the accuracy and feasibility of the WM scheme for single-phase three-level voltage source inverter.展开更多
The output current harmonic distortion of a three-level inverter is less than the traditional twolevel inverter.The voltage stress of the semiconductor switch is low.A neutral point potential drift control method is p...The output current harmonic distortion of a three-level inverter is less than the traditional twolevel inverter.The voltage stress of the semiconductor switch is low.A neutral point potential drift control method is proposed to solve the problem of the neutral point potential drift of the three-level inverter.The interaction mechanism between the neutral point potential and the space voltage vector is presented.The small vector output by the inverter is found to be the root cause of the midpoint potential drift.It is found that the fluctuation of the midpoint potential could be suppressed by increasing the capacitance value of the inverter bus voltage stabilizing capacitor.Furthermore,it inhibits the fluctuation of the midpoint potential.The experimental results verify the efficiency and precision of the proposed method.展开更多
Ⅰ. INTRODUCTION MULTILEVEL inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters, such as lower common-mode voltage, lower d...Ⅰ. INTRODUCTION MULTILEVEL inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters, such as lower common-mode voltage, lower dv/dt, lower harmonics in output voltage and current, and reduced voltage on the power switches.展开更多
Modeling and simulation of induction motor drive system to investigate and mitigate the adverse effects of PWM inverter based on analysis, modeling and simulation are presented. The estimation of conducted disturbance...Modeling and simulation of induction motor drive system to investigate and mitigate the adverse effects of PWM inverter based on analysis, modeling and simulation are presented. The estimation of conducted disturbances and other adverse effects of PWM inverter by simulation offer a considerable gain from the economic point of view. For an accurate model of the motor drive system including mains, rectifier, inverter, motor and its long cables, the high frequency parasitic current paths are taken into account. The novel model and its parasitic values for three-phase induction motor system are presented. Finally a new solution for suppressing EMI, common mode voltage, leakage current, bearing current and shaft voltages is proposed and the results show the excellent performances of proposed solution including active and passive filters.展开更多
In cascaded H-bridge multilevel inverter, a variable frequency inverted sine PWM technique is modeled for hybrid electric vehicles. It has a particular advantage of increasing power which is achieved using series conn...In cascaded H-bridge multilevel inverter, a variable frequency inverted sine PWM technique is modeled for hybrid electric vehicles. It has a particular advantage of increasing power which is achieved using series connection of H-bridge and also this topology is capable to produce superior spectral quality with considerable improvement of fundamental voltage. The variable frequency inverted sine PWM technique produces lesser torque ripple and enhances the fundamental output voltage mainly at lower modulation index ranges. The topologies of multilevel inverter are flying capacitor, diode clamped and cascaded inverter. In the paper, we will discuss about the cascaded multilevel inverter based on inverted sine PWM technique. The two switching strategies widely used to control multilevel inverters are constant frequency inverted sine PWM (CF-ISPWM) and variable frequency inverted sine PWM (VF-ISPWM). This implies that switch utilization substantially reduces 32.35% of the constant frequency inverted sine PWM switching technique. The performance of the technique is validated in terms of Total Harmonic Distortion (THD) and Torque ripple which significantly reduces when compared to constant frequency ISPWM. The analysis of conventional triangular PWM inverter and inverted sine PWM inverter using constant and variable switching scheme is done in MATLAB Simulink and verified experimentally by FPGA Spartan 3E processor.展开更多
A new ride through strategy is introduced in a three-level dual Z-source inverter, for isolation under semiconductor switching failure condition. Here the output will have no significant decrease in the amplitude and ...A new ride through strategy is introduced in a three-level dual Z-source inverter, for isolation under semiconductor switching failure condition. Here the output will have no significant decrease in the amplitude and quality. Instead of diodes, the triacs are added to the inverter source ends, as it can perform a bidirectional power transfer also it can operate well in both low and high voltage operating conditions. The faulted part can be isolated by simply altering the firing pulses for turning on/off the triacs using the carrier based SPWM technique and resulting in a boosting output with zero common mode voltage. Consequently, it forms a common floating point or null point with a zero common mode voltage. It is experimentally verified by using MATLAB, and digital oscilloscope.展开更多
This paper proposes a high performance three-level inverter Neutral Point Clamped (NPC) structure for photovoltaic system. The proposed configuration which can boost the low voltage of photovoltaic (PV) array, can als...This paper proposes a high performance three-level inverter Neutral Point Clamped (NPC) structure for photovoltaic system. The proposed configuration which can boost the low voltage of photovoltaic (PV) array, can also convert the photovoltaic DC power into high quality AC power. Attention has been paid to the problem of neutral point potential variation. In this way, a Direct Torque Control (DTC) technique has been applied and the estimated value of the Neutral Point Potential (NPP) is used, which is calculated by motor currents. This control strategy uses the redundancy presented by the inverter for selecting appropriate switching state through a switching table to achieve the control of NPP. This study shows the effect of the stability problem of the DC voltages and good static and dynamic performances were obtained in simulation of the proposed cascade “photovoltaic cell-three-level NPC VSI-induction motor”.展开更多
The multiplicity of vector combinations for vectors of combined three-level inverters plays an important role, when deciding on the modulation scheme, to obtain minimum switching per inverter vector change, as describ...The multiplicity of vector combinations for vectors of combined three-level inverters plays an important role, when deciding on the modulation scheme, to obtain minimum switching per inverter vector change, as described in the next Section. This is not possible with reduced common-mode three-level inverter structure, obtained with a five-level cascaded H-bridge configuration, as the space vectors locations do not exhibit multiplicity. Moreover, the proposed configuration requires only two power supplies, whereas the scheme with the five-level H-bridge configuration requires six isolated power supplies.展开更多
The multiplicity of vector combinations for vectors of combined three-level inverters plays an important role, when deciding on the modulation scheme, to obtain minimum switching per inverter vector change, as describ...The multiplicity of vector combinations for vectors of combined three-level inverters plays an important role, when deciding on the modulation scheme, to obtain minimum switching per inverter vector change, as described in the next Section. This is not possible with reduced common-mode three-level inverter structure, obtained with a five-level cascaded H-bridge configuration, as the space vectors locations do not exhibit multiplicity. Moreover, the proposed configuration requires only two power supplies, whereas the scheme with the five-level H-bridge configuration requires six isolated power supplies.展开更多
In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection sho...In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection short circuit at two switches any of the same phase leg in the inverter bridge and to achieve optimal harmonic of current, voltage. This paper presents two different control methods (CM) for ZSI. The aim of this study to compare between two modulation methods, there are modi?ed space vector pulse width modulation method (MSVM) and the simple boost control (SBC) about the unique harmonic performance features, the total average and peak switching device power of the inverter system. In addition, this paper also analyzes about the ability exceed modulation index in linear region of two CM using MATLAB/Simulink.展开更多
The intent of this paper is to analyze the electromagnetic signature of stator winding inter-turn short-circuit fault in a closed loop speed controlled Induction Motor(IM)employing Finite Element Method.Stator winding...The intent of this paper is to analyze the electromagnetic signature of stator winding inter-turn short-circuit fault in a closed loop speed controlled Induction Motor(IM)employing Finite Element Method.Stator winding short-circuit nearly covers 21%of faults in IM.Diagnosing the inter-turn fault at an incipient stage is one of the challenging task in the area of fault detection of IM to prevent crucial damages in industrial applications.Also detecting the faults in inverter fed IM under variable speed applications under varying load is one of the major issues in industrial drives.As the signatures of electromagnetic field contains the entire data in association with the location of rotor,stator and mechanical parts of the motor,a regular monitoring of fields in the airgap can be used to diagnose the inter-turn fault in the stator winding of IM.In this direction,an IM is modeled with several inter-turn fault severities like 30 turns,15 turns,5 turns&1 turn short using ANSYS Maxwell FEA tool and coupled with ANSYS Simplorer for loading arrangements.The PWM inverter with closed loop speed controlled strategy is implemented in Matlab Simulink and co-simulated with ANSYS Simplorer to integrate all the components in one common simulation platform environment for accurate design&analysis for realistic simulation.Several electromagnetic variables like flux density,flux lines and airgap flux density distribution over the machine are analyzed.The spatial FFT spectrum of radial component of flux density in the airgap contains the information related to the diagnosis of inter-turn fault at the incipient stage.展开更多
The new three-phase 5-level current-source inverter (CSI) proposed in this paper was developed by connecting three separate single-phase 5-level CSIs in series, and its operational principle was analyzed. There are tw...The new three-phase 5-level current-source inverter (CSI) proposed in this paper was developed by connecting three separate single-phase 5-level CSIs in series, and its operational principle was analyzed. There are two major problems existing in current-source multilevel inverters, one is the complex PWM control method (2-logic to 3-logic conversion), and the other is the problem of current-unbalance between different levels. A simple current-balance control method via DC current feedback is applied in each single-phase 5-level CSI cell to implement the current-balance control between different levels. And to reduce the output current harmonics, POD PWM control technique was used. Simulation and experimental results showed that this new three-phase 5-level CSI topology operates correctly.展开更多
基金supported by the Ming Chuan University Internal Research Fund
文摘A quasi resonant pulse width modulation(PWM) inverter is used in a solar power system to convert the solar panel and battery charger's direct current(DC) output to alternating current(AC).Although much has been published about DC to AC PWM inverters,none of the previous work has shown modeling and simulation results for DC to AC inverters.In this study,we suggest a new topology for a quasi resonant PWM inverter.Experimental results are also presented.
文摘Capacitor voltage imbalance is a significant problem for three-level inverters.Due to the mid-point modulation of these inverter topologies,the neutral point potential moves up or down depending on the neutral point current direction creating imbalanced voltages among the two capacitors.This imbalanced capacitor voltage causes imbalanced voltage stress among the semiconductor devices and causes increase output voltage and current harmonics.This paper introduces a modified voltage balancing strategy using two-level space vector modulation.By decomposing the three-level space vector diagram into two-level space vector diagram and redistributing the dwell times of the two-level zero space vectors,the modified voltage balancing method ensures minimal NP voltage ripple.Compared to the commonly used NP voltage control method(using 3L SVM[9]),the proposed modified NP voltage control method offers a slightly higher neutral-point voltage ripple and output voltage harmonics but,it has much lower switching loss,code size and execution time.
文摘In this paper, a new inverter topology dedicated to isolated or grid-connected PV systems is proposed. This inverter is based on the structures of a stacked multi-cell converter (SMC) and an H-bridge. This new topology has allowed the voltage stresses of the converter to be distributed among several switching cells. Secondly, divide the input voltage into several fractions to reduce the number of power semiconductors to be switched. In this contribution, the general topology of this micro-inverter has been described and the simulation tests developed to validate its operation have been presented. Finally, we discussed the simulation results, the efficiency of this topology and the feasibility of its use in a grid-connected photovoltaic production system.
文摘The full bridge zero voltage zero current switching ( FB-ZVZCS ) , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.
文摘In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter are added to input circuit of the inverter.Single-phrase full-bridge inverter performs the function of converting direct current into alternating current(DC/AC).In the control circuit,single chip micyoco(SCM)AT89C2051 is used for main control chip to accomplish the hardware design of the control system.A given value of output frequency of the inverter is input in the way of coding.According to the output frequency code which is read,SCM AT89C2051 defined harmonic elimination PWM control data which will be selected.Through internal timing control,the switches are switched under this provision of PWM control data.Then the driving signals of the switches in the inverter are output from I/O of SCM AT89C2051 to realize harmonic elimination PWM control.The results show that adding Newton homotopic algorithm of harmonic elimination PWM control to corresponding software of the control system can make the quality of output voltage of the inverter higher and it will have broad application prospects.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51107016)
文摘The single-phase three-level voltage source inverter based on wavelet modulation(WM) is proposed.The WM technique is based on constructing a nondyadic-type multi-resolution analysis(MRA),which supports sampling continuous-time sinusoidal signals in a nonuniform recurrent manner,and then reconstructing it by using inverter switching actions. In order to further improve the output voltage waveform and reduce harmonic distortion,the wavelet modulation is used to three-level inverter. The high magnitude of fundamental component and significantly reduced harmonic contents of the inverter output voltage can be achieved by using WM in the single-phase three-level voltage source inverter. Furthermore,the WM algorithm is implemented by using only one element government(EV) in DSP. The simulated and experimental results prove the accuracy and feasibility of the WM scheme for single-phase three-level voltage source inverter.
基金the National Natural Science Foundation of China(No.51407007)。
文摘The output current harmonic distortion of a three-level inverter is less than the traditional twolevel inverter.The voltage stress of the semiconductor switch is low.A neutral point potential drift control method is proposed to solve the problem of the neutral point potential drift of the three-level inverter.The interaction mechanism between the neutral point potential and the space voltage vector is presented.The small vector output by the inverter is found to be the root cause of the midpoint potential drift.It is found that the fluctuation of the midpoint potential could be suppressed by increasing the capacitance value of the inverter bus voltage stabilizing capacitor.Furthermore,it inhibits the fluctuation of the midpoint potential.The experimental results verify the efficiency and precision of the proposed method.
文摘Ⅰ. INTRODUCTION MULTILEVEL inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters, such as lower common-mode voltage, lower dv/dt, lower harmonics in output voltage and current, and reduced voltage on the power switches.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50477009).
文摘Modeling and simulation of induction motor drive system to investigate and mitigate the adverse effects of PWM inverter based on analysis, modeling and simulation are presented. The estimation of conducted disturbances and other adverse effects of PWM inverter by simulation offer a considerable gain from the economic point of view. For an accurate model of the motor drive system including mains, rectifier, inverter, motor and its long cables, the high frequency parasitic current paths are taken into account. The novel model and its parasitic values for three-phase induction motor system are presented. Finally a new solution for suppressing EMI, common mode voltage, leakage current, bearing current and shaft voltages is proposed and the results show the excellent performances of proposed solution including active and passive filters.
文摘In cascaded H-bridge multilevel inverter, a variable frequency inverted sine PWM technique is modeled for hybrid electric vehicles. It has a particular advantage of increasing power which is achieved using series connection of H-bridge and also this topology is capable to produce superior spectral quality with considerable improvement of fundamental voltage. The variable frequency inverted sine PWM technique produces lesser torque ripple and enhances the fundamental output voltage mainly at lower modulation index ranges. The topologies of multilevel inverter are flying capacitor, diode clamped and cascaded inverter. In the paper, we will discuss about the cascaded multilevel inverter based on inverted sine PWM technique. The two switching strategies widely used to control multilevel inverters are constant frequency inverted sine PWM (CF-ISPWM) and variable frequency inverted sine PWM (VF-ISPWM). This implies that switch utilization substantially reduces 32.35% of the constant frequency inverted sine PWM switching technique. The performance of the technique is validated in terms of Total Harmonic Distortion (THD) and Torque ripple which significantly reduces when compared to constant frequency ISPWM. The analysis of conventional triangular PWM inverter and inverted sine PWM inverter using constant and variable switching scheme is done in MATLAB Simulink and verified experimentally by FPGA Spartan 3E processor.
文摘A new ride through strategy is introduced in a three-level dual Z-source inverter, for isolation under semiconductor switching failure condition. Here the output will have no significant decrease in the amplitude and quality. Instead of diodes, the triacs are added to the inverter source ends, as it can perform a bidirectional power transfer also it can operate well in both low and high voltage operating conditions. The faulted part can be isolated by simply altering the firing pulses for turning on/off the triacs using the carrier based SPWM technique and resulting in a boosting output with zero common mode voltage. Consequently, it forms a common floating point or null point with a zero common mode voltage. It is experimentally verified by using MATLAB, and digital oscilloscope.
文摘This paper proposes a high performance three-level inverter Neutral Point Clamped (NPC) structure for photovoltaic system. The proposed configuration which can boost the low voltage of photovoltaic (PV) array, can also convert the photovoltaic DC power into high quality AC power. Attention has been paid to the problem of neutral point potential variation. In this way, a Direct Torque Control (DTC) technique has been applied and the estimated value of the Neutral Point Potential (NPP) is used, which is calculated by motor currents. This control strategy uses the redundancy presented by the inverter for selecting appropriate switching state through a switching table to achieve the control of NPP. This study shows the effect of the stability problem of the DC voltages and good static and dynamic performances were obtained in simulation of the proposed cascade “photovoltaic cell-three-level NPC VSI-induction motor”.
文摘The multiplicity of vector combinations for vectors of combined three-level inverters plays an important role, when deciding on the modulation scheme, to obtain minimum switching per inverter vector change, as described in the next Section. This is not possible with reduced common-mode three-level inverter structure, obtained with a five-level cascaded H-bridge configuration, as the space vectors locations do not exhibit multiplicity. Moreover, the proposed configuration requires only two power supplies, whereas the scheme with the five-level H-bridge configuration requires six isolated power supplies.
文摘The multiplicity of vector combinations for vectors of combined three-level inverters plays an important role, when deciding on the modulation scheme, to obtain minimum switching per inverter vector change, as described in the next Section. This is not possible with reduced common-mode three-level inverter structure, obtained with a five-level cascaded H-bridge configuration, as the space vectors locations do not exhibit multiplicity. Moreover, the proposed configuration requires only two power supplies, whereas the scheme with the five-level H-bridge configuration requires six isolated power supplies.
文摘In recent years, Z-source inverters (ZSI) have been proposed as an replacement power conversion concept which it has both voltage buck and boost abilities. In addition, ZSI doesn’t require dead-time to protection short circuit at two switches any of the same phase leg in the inverter bridge and to achieve optimal harmonic of current, voltage. This paper presents two different control methods (CM) for ZSI. The aim of this study to compare between two modulation methods, there are modi?ed space vector pulse width modulation method (MSVM) and the simple boost control (SBC) about the unique harmonic performance features, the total average and peak switching device power of the inverter system. In addition, this paper also analyzes about the ability exceed modulation index in linear region of two CM using MATLAB/Simulink.
文摘The intent of this paper is to analyze the electromagnetic signature of stator winding inter-turn short-circuit fault in a closed loop speed controlled Induction Motor(IM)employing Finite Element Method.Stator winding short-circuit nearly covers 21%of faults in IM.Diagnosing the inter-turn fault at an incipient stage is one of the challenging task in the area of fault detection of IM to prevent crucial damages in industrial applications.Also detecting the faults in inverter fed IM under variable speed applications under varying load is one of the major issues in industrial drives.As the signatures of electromagnetic field contains the entire data in association with the location of rotor,stator and mechanical parts of the motor,a regular monitoring of fields in the airgap can be used to diagnose the inter-turn fault in the stator winding of IM.In this direction,an IM is modeled with several inter-turn fault severities like 30 turns,15 turns,5 turns&1 turn short using ANSYS Maxwell FEA tool and coupled with ANSYS Simplorer for loading arrangements.The PWM inverter with closed loop speed controlled strategy is implemented in Matlab Simulink and co-simulated with ANSYS Simplorer to integrate all the components in one common simulation platform environment for accurate design&analysis for realistic simulation.Several electromagnetic variables like flux density,flux lines and airgap flux density distribution over the machine are analyzed.The spatial FFT spectrum of radial component of flux density in the airgap contains the information related to the diagnosis of inter-turn fault at the incipient stage.
基金Project (No. 50477033) supported by the National Natural Science Foundation of China
文摘The new three-phase 5-level current-source inverter (CSI) proposed in this paper was developed by connecting three separate single-phase 5-level CSIs in series, and its operational principle was analyzed. There are two major problems existing in current-source multilevel inverters, one is the complex PWM control method (2-logic to 3-logic conversion), and the other is the problem of current-unbalance between different levels. A simple current-balance control method via DC current feedback is applied in each single-phase 5-level CSI cell to implement the current-balance control between different levels. And to reduce the output current harmonics, POD PWM control technique was used. Simulation and experimental results showed that this new three-phase 5-level CSI topology operates correctly.