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This paper discusses systematic efficiency considering the efficiency of both a motor and airflow in an inverter-driven single-phase brushless direct-current (BLDC) motor with two different lamination designs for a cordless vacuum cleaner. In other words, multi-physical lamination design has to be conducted, and hence, the shape and placement of a whole electromagnetic structure are investigated in terms of a tradeoff between the electrical and mechanical efficiencies. In this paper, a single-phase BLDC motor for cordless vacuum cleaners is designed to satisfy starting and continuous torques by means of asymmetric air gap, and fluid analysis is performed to determine which shape of a single-phase BLDC motor has better system efficiency. The prototype of a single-phase BLDC motor has been tested, and the speed of the operation is ranged from 84468 r/min up to the rated speed of 100020 r/min. The motor efficiency of 94.7% has been measured to verify a good match with the estimated efficiency of 94.5%. [ABSTRACT FROM AUTHOR]

In this paper, we develop and examine permanent magnet synchronous motors (PMSMs) by use of both stator and rotor cores made of nanocrystalline magnetic materials (NMMs). We report core loss properties of the PMSM with the NMM under inverter excitation. In addition, we compare core losses of the PMSM with conventional non-oriented (NO) steel sheets under inverter excitation to discuss the core loss characteristics of the NMM motor. In average, under inverter excitation, the reduction ratio in core loss of the PMSM made of NMM is about 60% as compared with the core loss of the PMSM with NO sheets. In particular, the average decrease obtained by using NMM rotor core instead of NO rotor core is about 30%. [ABSTRACT FROM AUTHOR]

This paper investigates both the fundamental and harmonic losses of permanent magnet synchronous motor (PMSM) in conjunction with inverter losses for a wide range of switching frequencies (SFs) and different direct-axis currents (Ids) under full power range. The effects of SFs and Ids on the total losses, including fundamental loss and harmonic loss in the windings and lamination core, conduction loss, and switching loss in IGBTs, are described through analytical models. Meanwhile, the loss models of the motor are modified and validated by the 2-D finite-element analysis. Furthermore, the efficiency improvement of the overall PMSM-inverter system for different operation conditions benefits from an artificial bee colony (ABC) algorithm proposed in this paper. The optimal SF and Id, in terms of PMSM-inverter overall efficiency, are preferred for every operation point, thanks to the proposed ABC and the precise calculation of losses. Experimental results validate the proposed methodology. [ABSTRACT FROM PUBLISHER]

This paper proposes a common-mode electromagnetic interference (CM-EMI) spectrum calculation method based on double Fourier series for photovoltaic (PV) inverters with chaotic sinusoidal pulsewidth modulation (CSPWM). In this paper, the CM-EMI of a single-phase PV inverter is first analyzed, and the equivalent circuit of the CM-EMI in the single-phase PV inverter is established, then the CSPWM is employed to suppress the CM-EMI in PV inverters. Moreover, the proposed EMI spectrum calculation method based on double Fourier series is applied in evaluating the CM-EMI spectrum of the single-phase PV inverter. Finally, the simulation and experimental results validate the EMI suppression effectiveness of the CSPWM and the correctness of the proposed EMI spectrum calculation method. Therefore, the proposed EMI spectrum calculation method provides a theoretical support for CSPWM to reduce EMI. [ABSTRACT FROM AUTHOR]

High-speed permanent magnet machines, supplied by pulsewidth modulation (PWM) voltage source inverters, operate with distorted stator currents. Harmonics present in these stator currents deteriorate the machine performance by generating losses. Mostly, these losses are following the machine design using a transient finite-element model. The precise measurement of these rotor eddy-current losses is extremely difficult, hence, only a few papers provide convincing comparisons between predictions and measurements. This paper presents a fast and precise analytical approach, verified with measurements, to consider rotor losses of machines, supplied by PWM voltages, already during the design procedure. [ABSTRACT FROM AUTHOR]

The effects of temperature-dependent material properties, including those of silicon steel and permanent magnet (PM) materials, on the design process of inverter-fed PM motors are investigated in this paper. The magnetization curves of these materials are measured experimentally at different temperatures and are imported into a finite-element package. Then, a statistical study of an integrated motor-drive system consisting of an interior PM motor connected to a space vector modulated inverter is performed by assigning four different temperatures and building a design space of various objectives including the integrated system efficiency, speed limits, motor startup quality, torque ripple, total harmonic distortion, and power factor as the geometrical dimensions are varied. The results reveal that incorporating the realistic material properties into the design process is essential. Moreover, different motor-drive performances have totally different variation rates as the material properties are changed. Finally, a set of optimal designs at different temperatures is proposed to show the effect of changing material properties. [ABSTRACT FROM AUTHOR]

Large amounts of harmonics are contained in the current as the motor is driven by pulse width modulation (PWM). Significant amounts of computing time are required to compute local flux density variation considering such current harmonics. Since the amplitudes of higher harmonics are significantly smaller than that of fundamental harmonic, flux density variations due to the higher harmonics are small, and the relationship between the field strength and flux density can be assumed to be linear. When the operating point of each element is known, flux density variations for the higher harmonics can be analyzed by linear finite-element analysis (FEA). This paper suggests a method to calculate flux density variations in the iron core while taking into considering PWM current harmonics. First, the operating point solution is obtained by nonlinear FEA, second each element is linearized. Then, the flux density for the PWM current is obtained through linear FEA. Finally, the obtained results are presented and compared with nonlinear FEA results for verification. [ABSTRACT FROM AUTHOR]

Recently, novel magnetic materials have been developed for high-efficiency and high power density electric motors. In addition, next-generation semiconductor devices, like silicon carbide (SiC) or gallium nitride (GaN), have been introduced for power converters due to their high-frequency operation. Therefore, high-frequency operation of new magnetic materials is possible when they are driven by GaN or SiC inverters. Nevertheless, iron loss characterization of magnetic materials when they are excited by high-frequency signals have not been conducted yet. This paper introduces the iron losses characterization of a magnetic material at high carrier frequency excitation using a GANFET inverter. This characterization was carried out by the experimental evaluation of iron losses at carrier frequencies from 5 to 500 kHz at different deadtimes. As a result of the measurements, iron losses seem to have a trend to increase at high carrier frequencies and large deadtimes. In addition, filtering is introduced and it seems to be an effective technique for reducing iron losses. [ABSTRACT FROM AUTHOR]

Recently, interior permanent magnet synchronous motor (IPMSM) is paying attention because of its high power density and efficiency by adopting permanent magnet. The IPMSM has two control methods: maximum torque per ampere (MTPA) control and flux weakening control. Generally, an MTPA control is applied to a continuous operating point, and in case of a startup point, input current is applied which satisfies required output torque. To control the IPMSM, the various types of inverters with current and voltage limitations are used. The motor cannot be operated if these limitations are not satisfied. This paper proposes a method to satisfy the current and voltage limitations of the inverter with two different operating points. By changing the control method of the rated operating point by a stack compensation method, the current and voltage limitations of the inverter can be satisfied at a startup operating point, where the input current in MTPA control at the continuous operating point cannot be satisfied. The proposed method is verified by a 2-D finite element analysis. [ABSTRACT FROM AUTHOR]

This paper provides new magnetic and electrical design guidelines for an integrated motor-drive system. Two significant design factors including the electric and magnetic loadings are targeted to address the issues associated with the combination of the motor and inverter performances. A set of new constraints is also introduced in terms of the magnetic, electrical and thermal limits of a field oriented controlled permanent magnet (PM) motor to highlight the corresponding design challenges. Moreover, the demagnetization proximity limit is incorporated to ensure a reliable and safe operation of the PM material. The results show that the magnetic and electrical requirements of an optimum integrated system are totally different from the optimum performances of either side of the system, i.e., the motor or the inverter. Finally, an efficiency/robustness trade-off is proposed and applied to the investigated motor-drive system to return a reliable and efficient design. [ABSTRACT FROM AUTHOR]

A new method for fast calculating the permanent magnet (PM) eddy current losses (ECLs) in interior PM synchronous machine caused by the high-frequency harmonic voltages (HFHVs) under pulsewidth modulation (PWM) voltage source inverter supply is proposed, by which time-consuming transient finite element analysis (FEA) is eliminated and the influence of the axial segmentation on the PM ECLs can be taken into consideration. The combination of the fixed differential permeability method and the linear frequency FEA is proposed to investigate the relationship between arbitrary HFHV and the corresponding PM ECL at different load conditions. The analytical model proposed in the previous published paper is used to describe this relationship quantitatively. Finally, the total PM ECLs at different load conditions can be calculated based on the fast Fourier transform results of the input PWM voltages. The relative errors between the total losses obtained with the proposed method and those with time-stepping FEA are within 21% at four typical load conditions, and the proposed method can reduce the computation time for one load condition to few minutes considering arbitrary PM axial segmentation. [ABSTRACT FROM AUTHOR]

This paper introduces the periodic carrier frequency modulation (PCFM) for permanent magnet synchronous motor (PMSM) drive systems so as to reduce the low-frequency electromagnetic interference (EMI). PMSMs are widely used in many applications and they are usually fed by pulsewidth modulation (PWM) inverters. The EMI of PMSM, which results from the switch of power device, generates undesirable effects on the control system. Therefore, it is of importance to reduce the EMI of PMSM. The common mode (CM) conducted EMI model of the PMSM drive system is constructed to investigate the CM voltage. The simulations and experiments of PMSM fed by the fixed frequency PWM (FFPWM) and PCFM are implemented to analyze the CM conducted EMI. The CM EMI spectra of PMSM fed by the FFPWM and PCFM with different spreading frequency widths are compared to explore the influence of PCFM on the CM conducted EMI. The regular patterns on PCFM in reducing the CM conducted EMI of PMSM drive systems are revealed. [ABSTRACT FROM AUTHOR]

We calculate an iron loss attributed to semiconductors ON-voltages in an inverter circuit and reveal influence rate of the ON-voltages on whole iron loss. In our previous work, it has been revealed by inverter excitation that the ON-voltages make minor loops in magnetic hysteresis of magnetic material and the loops affect iron loss characteristics. In this paper, it is investigated by a factor analysis how much the on-voltage has an influence on iron loss, quantitatively. We separate whole iron loss caused in a non-oriented electrical steel sheet into three losses: loss by the ON-voltage, loss by fundamental component, and loss by inverter carrier. The rates of these losses are evaluated under several conditions of single-phase pulse width modulation inverter excitation, and the results show that the proportion of loss by ON-voltages is up to around 10% depending on inverter excitation parameter: fundamental frequency, carrier frequency, modulation index, and magnetic flux density. [ABSTRACT FROM PUBLISHER]

In this paper, the investigation is focused on the iron loss prediction for electrical machines fed by low switching frequency inverter. An improved iron loss model is developed after reviewing various existing iron loss models considering pulse-width modulation (PWM) influence. In order to validate the improved iron loss model, iron loss tests are carried out on an electrical machine. The predicted iron loss results match well with the measured results, which shows that the improved iron loss model is able to predict iron loss in electrical machine fed by an inverter. The comparison between the predicted iron losses with and without considering the PWM influence shows that the iron loss can be significantly increased due to the influence of PWM, especially when the switching frequency is low. [ABSTRACT FROM AUTHOR]

To evaluate how magnetic properties of magnetic materials are influenced by power semiconductor properties in an inverter circuit, we propose and test a new numerical calculation method. This method combines an electrical circuit analysis for current–voltage properties of power semiconductors with a magnetic analysis based on a magnetic hysteresis model. Previous measurements on an inverter show that magnetic properties, such as B–H curves (B is the magnetic flux density and H is the magnetic field intensity) and iron losses, are affected by ON-voltages of power semiconductors. Those measurements motivate this paper. The magnetic hysteresis model used here is a novel approach that is based on physical thermodynamics theory and can capture the essence of physical magnetic phenomena. Calculations with the proposed method show that measured minor loops in B–H curves are well represented and calculated voltage waveforms properly capture ON-voltage effects. [ABSTRACT FROM AUTHOR]

An automatic shape optimization procedure that estimates the inverter carrier harmonic losses generated at cores and magnets has been developed in order to improve the performance of interior permanent magnet motors used for variable speed/load applications. In the proposed procedure, an electromagnetic field analysis coupled with armature voltage equation is iteratively carried out at each rotor shape. The input of this analysis is the theoretical inverter voltage, which is determined by both the rotor shape and the driving conditions of the motor. The proposed procedure is applied to a 100 kW-class interior permanent magnet motor, in which the carrier harmonic losses become dominant under frequent driving conditions. It is clarified that the carrier harmonic losses can be reduced by more than 10%, whereas the other important characteristics are not deteriorated. [ABSTRACT FROM AUTHOR]