IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, 2017
Wireless power transfer has been introduced as a proper replacement for conventional cable power ... more Wireless power transfer has been introduced as a proper replacement for conventional cable power transfer systems recently. With the developments of the electric transportation, transferring power wirelessly has been found to introduce several advantages in charging Lithium-Ion batteries. Among different configurations of wireless power transfer, Series Parallel structure is found to be more interesting in high power applications, because of its high voltage gain. This paper investigates almost consistent output voltage of a wireless power transfer system with fixed switching frequency which fits Lithium-Ion battery charging profiles. Moreover, ZVS operation of the switches in rated power is guaranteed in order to avoid MOSFETs switching losses. A method for selecting the compensation capacitors is introduced. Simulation and experimental results are used to verify the theory.
IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society, 2020
Gallium nitride (GaN) transistors have demonstrated their potential as a high switching frequency... more Gallium nitride (GaN) transistors have demonstrated their potential as a high switching frequency, high power density, and high-efficiency power device. There has been substantial research undertaken on the switching and conduction losses calculation, where most studies have calculated them using an analytical approach. This paper presents an interpolation-based method to calculate switching and conduction losses. This interpolation method employs a combination of the GaN transistor and driving parameters such as parasitic capacitances, parasitic inductances, gate resistors, drain-to-source voltage, instantaneous current, and temperature. A value for switching loss is considered as a base value and the different combinations of circuits will be reached by using interpolated equations. The second aim of this study is to investigate the temperature-dependency of the ON state resistance: two values at different temperatures are considered and ON resistance will be obtained by linear in...
This paper proposes a straightforward control method for voltage control of a three-phase transfo... more This paper proposes a straightforward control method for voltage control of a three-phase transformer-based inverter in uninterruptible power supplies or distributed generation systems. The approach offers a dual-loop design consisting inner current control loop and outer voltage loop. Sliding mode current controller provides desired bandwidth for voltage controller which consists of a state feedback term for stabilization and resonant term for harmonic damping. The proposed scheme provides fast dynamic response and low total harmonic distortion even for high power inverters with the limitations of switching frequency and LC filter components. Experimental studies for 2KVA linear and nonlinear loads using digital signal processors validate excellent performance of the proposed method.
In this paper a method for stabilization of a two-mass drive system with flexible couplings is su... more In this paper a method for stabilization of a two-mass drive system with flexible couplings is suggested. The proposed method is based on the extra degree of freedom provided by the fractional-order of integration in PI controllers and the adopted design technique uses the stability regions in the controller parameter space to ensure closed-loop stability. The designed control structure has the advantage of not requiring any additional feedback measurements and it is implementable within the framework of traditional PI control structures.
Proportional integral (PI) or proportional resonant (PR) controller are the most popular controll... more Proportional integral (PI) or proportional resonant (PR) controller are the most popular controllers used to shape the current of voltage sourced converters. Besides, current harmonics are inevitably generated while using a three-phase PWM rectifiers. Since the bandwidth of the controller is usually not fast enough to compensate for the generated harmonics, the harmonics are not removed. Selective harmonic compensation is the most popular for compensation of hormoics. This approach, however, needs a significant time for its calculations, as elimination of each harmonic requires its resonant filter. Moreover, to utilize the average current mode technique, the switching frequency of the converter should be synchronized with the sampling frequency of the analog to digital converter (ADC), and the bandwidth of the current controller, as a rule of thumb, should be limited to one-tenth of the switching frequency. This paper proposes a novel elimination approach which suppresses the harmon...
IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society
Resonant converters are hard nonlinear systems which are comprised of both continuous and discont... more Resonant converters are hard nonlinear systems which are comprised of both continuous and discontinuous nonlinearities. Many nonlinear modeling approaches lead to a very awkward, unsystematic stability analysis and controller design. Hence, stability analysis and stabilizing controller design of the popular LLC resonant converter still remain challenging as direct consequences of the absence of a “systematic modeling”. In this paper, the LLC resonant converter is modeled in the form of Piece-Wise Affine (PWA) systems and a Direct Piece-Wise Affine (DPWA) model of the DC-DC LLC resonant converter is proposed. No dynamic is omitted in the modeling approach, and accordingly, the proposed “systematic model” is exact and can be utilized in a precise, systematic stability analysis and controler design. In addition, using the method, no voltage controlled oscillator is needed to control the resonant converter.
This paper offers a holistic model and approach on reliability assessment of conventional isolate... more This paper offers a holistic model and approach on reliability assessment of conventional isolated multi-switch pulse width modulation DC-DC (IMSDC-DC) power electronic converters with conventional half-bridge, full-bridge, and pushpull DC-DC topologies. The proposed reliability assessment analytics encapsulate correlated effects of several conditions (e.g., open and short-circuit faults) and prevailing parameters (e.g., duty cycle, input voltage, output power, transformer turns ratio, voltage gain, switching frequency, operation time duration and components characteristics) on the overall reliability performance of IMSDC-DC converters. Such insights are then harnessed within a Markov process to characterize and evaluate the mean time to failure (MTTF) reliability metrics for IMSDC-DC in both continues and discontinuous conduction modes. Numerical results are followed with experimental verifications to demonstrate the self-embedded fault tolerant capability of the IMSDC-DC topologies.
Control and stabilisation of the resonant converters are essential problems in power electronics.... more Control and stabilisation of the resonant converters are essential problems in power electronics. The conventional model of the dc–dc series resonant converter (SRC) is derived using the sinusoidal approximation and generalised averaging followed by linearisation about an operating point. This model involves considerable approximation and is not applicable for large variation of load and supply voltage. The authors have already proposed a direct piece-wise affine (DPWA) modelling and control approach for the SRC that operates above resonant frequency. However, the DPWA technique is not applicable to an SRC that operates below resonance because of the presence of harmonics. In this study, a dynamic voltage-controlled oscillator (VCO) is introduced, so that the overall system consisting of the proposed VCO following by the SRC is modelled as a PWA system. Then, a hybrid controller is designed in order to regulate the dc output voltage of the SRC operating below resonance. Also, the stability analysis of the closed-loop system is presented in the form of linear matrix inequalities. A prototype of the SRC is constructed and the proposed hybrid controller is implemented on a digital signal processor (DSP) core. The simulation and experimental results show the effectiveness of this modelling and control approach.
2016 7th Power Electronics and Drive Systems Technologies Conference (PEDSTC), 2016
In optimum designing of wireless power transfer (WPT) coils, maximum efficiency and maximum power... more In optimum designing of wireless power transfer (WPT) coils, maximum efficiency and maximum power transfer capability of coils should be considered. In this paper, a novel technique for optimum design of WPT coils based on maximum efficiency with considering required power transfer capability has been given. Optimum selection of system parameters including coil and wire dimensions, number of turns of coils and compensation capacitor selection based on minimum weight of copper mass is also given. For evaluation purpose a 100W experimental sample is designed and tested in 20cm range.
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES
Flux reversal permanent magnet generators are well suited for use as wind turbine generators owin... more Flux reversal permanent magnet generators are well suited for use as wind turbine generators owing to their high torque generation ability and magnetic gear. However, they suffer from poor voltage regulation due to their high winding inductance. In this paper, a design optimization method is proposed for flux reversal generators in wind turbine applications. The proposed method includes a new multiobjective function. Cost, volume of the generator, and mass of the permanent magnet are considered in it independently and simultaneously. Besides the new objective function, the main superiority of this paper compared with published papers is considering winding inductance in optimization procedures as a constraint and analyzing the optimization results for different values of it. Also, for the first time, the equations for permanent magnet sizing are considered based on a demagnetization curve for designing a flux reversal generator. For this purpose, a step-by-step design procedure is proposed and sensitivity analysis is performed to determine the sensitivity of output parameters to specific electrical loading, the height of the permanent magnets, and the machine length-to-diameter ratio. Then a multiobjective optimization based on a genetic algorithm is carried out and the best combination of pole number and number of slots/pole/phase is obtained. Then, for this combination, the optimum value of the constraint is obtained, too. Then specifications and dimensions of the optimum flux reversal machine as a wind turbine generator is presented. Finally, a time-stepping finite element method is used to validate the design and optimization results.
This paper sets forth the reliability analysis of conventional isolated pulse width modulation DC... more This paper sets forth the reliability analysis of conventional isolated pulse width modulation DC-DC (IDC-DC) converters. The IDC-DC converters are categorized into isolated single-switch DC-DC (ISSDC-DC) or multiple-switch DC-DC (IMSDC-DC) converters. The proposed framework encompasses analyzing the impacts of duty cycle, input voltage, output power, transformer turns ratio, components characteristics and time duration on the overall reliability performance of the IDC-DC converters. The suggested reliability assessment is centered on Markov models characterized by taking into consideration all open and short circuit faults on the components in both continuous and discontinuous conduction modes. We further investigate the self-embedded fault tolerant capability of the IMSDC-DC converters under open circuit fault scenarios on the switches, diodes and blocking capacitors, where we offer new reliability analytics. Along with extensive analyses and comparisons, several experimental results are provided to verify the self-embedded fault tolerant capability of IMSDC-DC converters. INDEX TERMS Isolated single-switch DC-DC converter (ISSDC-DC), isolated multiple-switch DC-DC converter (IMSDC-DC), fault analysis, Markov process, reliability.
Small Permanent Magnet Synchronous Generators (PMSGs) are widely used in small rooftop wind turbi... more Small Permanent Magnet Synchronous Generators (PMSGs) are widely used in small rooftop wind turbines. In order to inject the electric power generated by the PMSG, into the grid, a back-to-back AC/DC/AC converter is required. In this paper, a low cost with high efficiency converter is proposed for the rectifier stage to obtain the maximum power per ampere of PMSG. This structure based on Discontinuous Conduction Mode Single-Ended Primary Inductor Converter (DCM SEPIC) with a single power electronic switch, proposes a converter which is cost-effective and suitable for the small wind turbine used in residential applications. Furthermore, other advantages of the proposed converter include obtaining maximum power delivered per ampere using a simple control method and reducing the size of converter inductive filter by exploiting the PMSG internal synchronous reactance as part of the filter. Unlike the conventional DCM Boost rectifiers, the proposed converter has a continuous input current, which results in lower PMSG conduction loss. Operation principles and various operating modes of this converter are discussed in detail in this paper and verified by closed-loop simulation and experimental results for a 500W/200V prototype.
This paper proposes a comprehensive Markov model to study the reliability performance of the conv... more This paper proposes a comprehensive Markov model to study the reliability performance of the conventional isolated multiple-switch pulse width modulation DC-DC (IMSDC-DC) converters including full-bridge, half-bridge and push-pull DC-DC topologies. The suggested model helps to achieve more precise outcomes with a better reflection of the real-world operation characteristics by (i) relying on self-embedded fault tolerant capability of the IMSDC-DC converters, (ii) considering the probability of both short and open circuit (SC and OC) faults in each component, (iii) assessing the effect of semiconductors' SC/OC probability on the converters' reliability, (iv) analyzing the continuous and discontinuous conduction modes, (v) updating the operational characteristics of the converters after each fault occurrence, and (vi) evaluating control of the converters to have more durable power transfer in some post-fault cases. Then, the model is applied to assess the effects of duty cycle, output power, voltage gain and transformer turns ratio on the overall reliability and mean time to failure. Practical analytic conclusions are followed by some experimental results to verify the accuracy of the proposed model. INDEX TERMS Isolated multiple-switch pulse width modulation DC-DC (IMSDC-DC) converters, Markov model, mean time to failure (MTTF), open and short circuit faults, reliability analytics.
Direct drive permanent magnet synchronous generators have numerous advantages such as improved re... more Direct drive permanent magnet synchronous generators have numerous advantages such as improved reliability, low maintenance, long life, and developed performance characteristics. In recent years, many researchers have worked on this generator to enhance the performance of the generator, especially for the wind turbine application. The focus of this paper is on the development of a step-by-step method for the design of a permanent magnet synchronous generator. Then the winding function method is used to model the generator and calculate its output characteristics analytically. The analytical results of the designed generator are validated using the finite element analysis (FEA) and it is demonstrated that the obtained results from both methods are in great agreement with the experimental measurements of the Northern Power direct-drive generator. The sensitivity analysis and optimization procedure based on the genetic algorithm are used to design an optimum generator. The optimization goal is obtaining higher efficiency and power factor with lower voltage regulation and required permanent magnet volume compared to the initial design. In addition, the calculation of the voltage total harmonic distortion (THD) is presented and the optimum skew angle for the optimum generator is computed to reduce the voltage THD.
IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, 2017
Wireless power transfer has been introduced as a proper replacement for conventional cable power ... more Wireless power transfer has been introduced as a proper replacement for conventional cable power transfer systems recently. With the developments of the electric transportation, transferring power wirelessly has been found to introduce several advantages in charging Lithium-Ion batteries. Among different configurations of wireless power transfer, Series Parallel structure is found to be more interesting in high power applications, because of its high voltage gain. This paper investigates almost consistent output voltage of a wireless power transfer system with fixed switching frequency which fits Lithium-Ion battery charging profiles. Moreover, ZVS operation of the switches in rated power is guaranteed in order to avoid MOSFETs switching losses. A method for selecting the compensation capacitors is introduced. Simulation and experimental results are used to verify the theory.
IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society, 2020
Gallium nitride (GaN) transistors have demonstrated their potential as a high switching frequency... more Gallium nitride (GaN) transistors have demonstrated their potential as a high switching frequency, high power density, and high-efficiency power device. There has been substantial research undertaken on the switching and conduction losses calculation, where most studies have calculated them using an analytical approach. This paper presents an interpolation-based method to calculate switching and conduction losses. This interpolation method employs a combination of the GaN transistor and driving parameters such as parasitic capacitances, parasitic inductances, gate resistors, drain-to-source voltage, instantaneous current, and temperature. A value for switching loss is considered as a base value and the different combinations of circuits will be reached by using interpolated equations. The second aim of this study is to investigate the temperature-dependency of the ON state resistance: two values at different temperatures are considered and ON resistance will be obtained by linear in...
This paper proposes a straightforward control method for voltage control of a three-phase transfo... more This paper proposes a straightforward control method for voltage control of a three-phase transformer-based inverter in uninterruptible power supplies or distributed generation systems. The approach offers a dual-loop design consisting inner current control loop and outer voltage loop. Sliding mode current controller provides desired bandwidth for voltage controller which consists of a state feedback term for stabilization and resonant term for harmonic damping. The proposed scheme provides fast dynamic response and low total harmonic distortion even for high power inverters with the limitations of switching frequency and LC filter components. Experimental studies for 2KVA linear and nonlinear loads using digital signal processors validate excellent performance of the proposed method.
In this paper a method for stabilization of a two-mass drive system with flexible couplings is su... more In this paper a method for stabilization of a two-mass drive system with flexible couplings is suggested. The proposed method is based on the extra degree of freedom provided by the fractional-order of integration in PI controllers and the adopted design technique uses the stability regions in the controller parameter space to ensure closed-loop stability. The designed control structure has the advantage of not requiring any additional feedback measurements and it is implementable within the framework of traditional PI control structures.
Proportional integral (PI) or proportional resonant (PR) controller are the most popular controll... more Proportional integral (PI) or proportional resonant (PR) controller are the most popular controllers used to shape the current of voltage sourced converters. Besides, current harmonics are inevitably generated while using a three-phase PWM rectifiers. Since the bandwidth of the controller is usually not fast enough to compensate for the generated harmonics, the harmonics are not removed. Selective harmonic compensation is the most popular for compensation of hormoics. This approach, however, needs a significant time for its calculations, as elimination of each harmonic requires its resonant filter. Moreover, to utilize the average current mode technique, the switching frequency of the converter should be synchronized with the sampling frequency of the analog to digital converter (ADC), and the bandwidth of the current controller, as a rule of thumb, should be limited to one-tenth of the switching frequency. This paper proposes a novel elimination approach which suppresses the harmon...
IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society
Resonant converters are hard nonlinear systems which are comprised of both continuous and discont... more Resonant converters are hard nonlinear systems which are comprised of both continuous and discontinuous nonlinearities. Many nonlinear modeling approaches lead to a very awkward, unsystematic stability analysis and controller design. Hence, stability analysis and stabilizing controller design of the popular LLC resonant converter still remain challenging as direct consequences of the absence of a “systematic modeling”. In this paper, the LLC resonant converter is modeled in the form of Piece-Wise Affine (PWA) systems and a Direct Piece-Wise Affine (DPWA) model of the DC-DC LLC resonant converter is proposed. No dynamic is omitted in the modeling approach, and accordingly, the proposed “systematic model” is exact and can be utilized in a precise, systematic stability analysis and controler design. In addition, using the method, no voltage controlled oscillator is needed to control the resonant converter.
This paper offers a holistic model and approach on reliability assessment of conventional isolate... more This paper offers a holistic model and approach on reliability assessment of conventional isolated multi-switch pulse width modulation DC-DC (IMSDC-DC) power electronic converters with conventional half-bridge, full-bridge, and pushpull DC-DC topologies. The proposed reliability assessment analytics encapsulate correlated effects of several conditions (e.g., open and short-circuit faults) and prevailing parameters (e.g., duty cycle, input voltage, output power, transformer turns ratio, voltage gain, switching frequency, operation time duration and components characteristics) on the overall reliability performance of IMSDC-DC converters. Such insights are then harnessed within a Markov process to characterize and evaluate the mean time to failure (MTTF) reliability metrics for IMSDC-DC in both continues and discontinuous conduction modes. Numerical results are followed with experimental verifications to demonstrate the self-embedded fault tolerant capability of the IMSDC-DC topologies.
Control and stabilisation of the resonant converters are essential problems in power electronics.... more Control and stabilisation of the resonant converters are essential problems in power electronics. The conventional model of the dc–dc series resonant converter (SRC) is derived using the sinusoidal approximation and generalised averaging followed by linearisation about an operating point. This model involves considerable approximation and is not applicable for large variation of load and supply voltage. The authors have already proposed a direct piece-wise affine (DPWA) modelling and control approach for the SRC that operates above resonant frequency. However, the DPWA technique is not applicable to an SRC that operates below resonance because of the presence of harmonics. In this study, a dynamic voltage-controlled oscillator (VCO) is introduced, so that the overall system consisting of the proposed VCO following by the SRC is modelled as a PWA system. Then, a hybrid controller is designed in order to regulate the dc output voltage of the SRC operating below resonance. Also, the stability analysis of the closed-loop system is presented in the form of linear matrix inequalities. A prototype of the SRC is constructed and the proposed hybrid controller is implemented on a digital signal processor (DSP) core. The simulation and experimental results show the effectiveness of this modelling and control approach.
2016 7th Power Electronics and Drive Systems Technologies Conference (PEDSTC), 2016
In optimum designing of wireless power transfer (WPT) coils, maximum efficiency and maximum power... more In optimum designing of wireless power transfer (WPT) coils, maximum efficiency and maximum power transfer capability of coils should be considered. In this paper, a novel technique for optimum design of WPT coils based on maximum efficiency with considering required power transfer capability has been given. Optimum selection of system parameters including coil and wire dimensions, number of turns of coils and compensation capacitor selection based on minimum weight of copper mass is also given. For evaluation purpose a 100W experimental sample is designed and tested in 20cm range.
TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES
Flux reversal permanent magnet generators are well suited for use as wind turbine generators owin... more Flux reversal permanent magnet generators are well suited for use as wind turbine generators owing to their high torque generation ability and magnetic gear. However, they suffer from poor voltage regulation due to their high winding inductance. In this paper, a design optimization method is proposed for flux reversal generators in wind turbine applications. The proposed method includes a new multiobjective function. Cost, volume of the generator, and mass of the permanent magnet are considered in it independently and simultaneously. Besides the new objective function, the main superiority of this paper compared with published papers is considering winding inductance in optimization procedures as a constraint and analyzing the optimization results for different values of it. Also, for the first time, the equations for permanent magnet sizing are considered based on a demagnetization curve for designing a flux reversal generator. For this purpose, a step-by-step design procedure is proposed and sensitivity analysis is performed to determine the sensitivity of output parameters to specific electrical loading, the height of the permanent magnets, and the machine length-to-diameter ratio. Then a multiobjective optimization based on a genetic algorithm is carried out and the best combination of pole number and number of slots/pole/phase is obtained. Then, for this combination, the optimum value of the constraint is obtained, too. Then specifications and dimensions of the optimum flux reversal machine as a wind turbine generator is presented. Finally, a time-stepping finite element method is used to validate the design and optimization results.
This paper sets forth the reliability analysis of conventional isolated pulse width modulation DC... more This paper sets forth the reliability analysis of conventional isolated pulse width modulation DC-DC (IDC-DC) converters. The IDC-DC converters are categorized into isolated single-switch DC-DC (ISSDC-DC) or multiple-switch DC-DC (IMSDC-DC) converters. The proposed framework encompasses analyzing the impacts of duty cycle, input voltage, output power, transformer turns ratio, components characteristics and time duration on the overall reliability performance of the IDC-DC converters. The suggested reliability assessment is centered on Markov models characterized by taking into consideration all open and short circuit faults on the components in both continuous and discontinuous conduction modes. We further investigate the self-embedded fault tolerant capability of the IMSDC-DC converters under open circuit fault scenarios on the switches, diodes and blocking capacitors, where we offer new reliability analytics. Along with extensive analyses and comparisons, several experimental results are provided to verify the self-embedded fault tolerant capability of IMSDC-DC converters. INDEX TERMS Isolated single-switch DC-DC converter (ISSDC-DC), isolated multiple-switch DC-DC converter (IMSDC-DC), fault analysis, Markov process, reliability.
Small Permanent Magnet Synchronous Generators (PMSGs) are widely used in small rooftop wind turbi... more Small Permanent Magnet Synchronous Generators (PMSGs) are widely used in small rooftop wind turbines. In order to inject the electric power generated by the PMSG, into the grid, a back-to-back AC/DC/AC converter is required. In this paper, a low cost with high efficiency converter is proposed for the rectifier stage to obtain the maximum power per ampere of PMSG. This structure based on Discontinuous Conduction Mode Single-Ended Primary Inductor Converter (DCM SEPIC) with a single power electronic switch, proposes a converter which is cost-effective and suitable for the small wind turbine used in residential applications. Furthermore, other advantages of the proposed converter include obtaining maximum power delivered per ampere using a simple control method and reducing the size of converter inductive filter by exploiting the PMSG internal synchronous reactance as part of the filter. Unlike the conventional DCM Boost rectifiers, the proposed converter has a continuous input current, which results in lower PMSG conduction loss. Operation principles and various operating modes of this converter are discussed in detail in this paper and verified by closed-loop simulation and experimental results for a 500W/200V prototype.
This paper proposes a comprehensive Markov model to study the reliability performance of the conv... more This paper proposes a comprehensive Markov model to study the reliability performance of the conventional isolated multiple-switch pulse width modulation DC-DC (IMSDC-DC) converters including full-bridge, half-bridge and push-pull DC-DC topologies. The suggested model helps to achieve more precise outcomes with a better reflection of the real-world operation characteristics by (i) relying on self-embedded fault tolerant capability of the IMSDC-DC converters, (ii) considering the probability of both short and open circuit (SC and OC) faults in each component, (iii) assessing the effect of semiconductors' SC/OC probability on the converters' reliability, (iv) analyzing the continuous and discontinuous conduction modes, (v) updating the operational characteristics of the converters after each fault occurrence, and (vi) evaluating control of the converters to have more durable power transfer in some post-fault cases. Then, the model is applied to assess the effects of duty cycle, output power, voltage gain and transformer turns ratio on the overall reliability and mean time to failure. Practical analytic conclusions are followed by some experimental results to verify the accuracy of the proposed model. INDEX TERMS Isolated multiple-switch pulse width modulation DC-DC (IMSDC-DC) converters, Markov model, mean time to failure (MTTF), open and short circuit faults, reliability analytics.
Direct drive permanent magnet synchronous generators have numerous advantages such as improved re... more Direct drive permanent magnet synchronous generators have numerous advantages such as improved reliability, low maintenance, long life, and developed performance characteristics. In recent years, many researchers have worked on this generator to enhance the performance of the generator, especially for the wind turbine application. The focus of this paper is on the development of a step-by-step method for the design of a permanent magnet synchronous generator. Then the winding function method is used to model the generator and calculate its output characteristics analytically. The analytical results of the designed generator are validated using the finite element analysis (FEA) and it is demonstrated that the obtained results from both methods are in great agreement with the experimental measurements of the Northern Power direct-drive generator. The sensitivity analysis and optimization procedure based on the genetic algorithm are used to design an optimum generator. The optimization goal is obtaining higher efficiency and power factor with lower voltage regulation and required permanent magnet volume compared to the initial design. In addition, the calculation of the voltage total harmonic distortion (THD) is presented and the optimum skew angle for the optimum generator is computed to reduce the voltage THD.
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Papers by Farzad Tahami