新型混合励磁同步电机的数学模型与等效分析

为改善高速永磁电机磁场调节困难的问题,提出一种新型混合励磁电机,转子上既有永磁极又有铁心极,磁路呈现典型的径向、周向和轴向三维特性,难以直接用解析法求取电感参数。根据新型混合励磁电机的磁路特点,提出一种等效分析方法,将复杂磁路的混合励磁电机等效为三种二维磁路电机轴向并列叠加。为了提高新型混合励磁电机电磁设计与性能分析的效率,推导了其数学模型与电感参数表达式。对一台10 k W混合励磁原理样机进行了有限元分析与实验研究,结果验证了所提数学模型与等效分析方法的正确性,为该类电机的设计和优化提供了理论支撑。     

Short‐circuit current calculation and performance requirement of HVDC breakers for MMC‐MTDC systems

To evaluate the performance requirement of high‐voltage direct current (HVDC) breakers for modular multilevel converter (MMC)‐MTDC (multi‐terminal high voltage direct current) systems with high efficiency, the equivalent model for calculating the maximum short‐circuit current is presented in this paper. First, the short‐circuit current is decomposed into the steady‐state component and the fault component according to its physical dynamics. Second, the steady‐state component is determined by solving the direct current (DC) network; the fault component is calculated by an equivalent network in which the converters are replaced by a reactance, a resistance, and a capacitance in series. Then, the complete procedure for evaluating the performance requirement of HVDC breakers is described based on short‐circuit current calculation. Verifications have been carried out based on a three‐terminal 800 MW/±400 kV bipolar MMC‐MTDC system. The results show that the proposed methodology is efficient and effective. Lastly, based on the same system, the performance requirement of HVDC breakers and the influence by the sub‐module (SM) capacitance and the smoothing reactor have been studied with the proposed methodology. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Mover design and simulation of linear synchronous motor with half‐wave‐rectified self‐excitation

This paper presents a design method for a linear synchronous motor with half‐wave‐rectified self‐excitation; this method enables the construction of a motor with small thrust ripple. The mover of the motor is designed to be asymmetrical in order to reduce the thrust ripple. First, we design the configuration of the asymmetrical mover and the field winding of the mover by using the finite element method and a characteristic equation. The asymmetrical mover is built, and the thrust ripple reduction is verified by experiments. Next, the linear synchronous motor is modeled using a circuit simulator in order to confirm its high‐speed performance. The operation characteristics are clarified by simulation. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(1): 43–52, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21051     

混合励磁同步电机调速系统的控制策略

为了研究混合励磁同步电机(HESM)调速系统的有效控制策略,推导出HESM在dq0坐标系统下的数学模型,设计了基于矢量控制的HESM调速系统,提出了HESM调速系统的分区控制策略及其实现方法.采用MATLAB软件下的Simulink/PSB工具箱,建立了HESM调速系统的仿真模型,并根据不同目的要求,设计了不同的仿真方法,分析了HESM调速系统在低速标准调速区、低速增磁调速区及高速弱磁调速区的调速特性,并与PMSM调速系统进行了仿真比较.结果表明,HESM调速系统比PMSM调速系统具有更高的恒转矩输出和更宽的恒功率运行范围,且增磁励磁电流给定通道的调节能提高电机动态响应速度.     

Analysis of a self‐regulated,self‐excited,brushless three‐phase synchronous generator,which includes the effect of core losses

This paper presents a novel analysis of a self‐regulated, self‐excited, brushless three‐phase synchronous generator, which includes the effect of core losses. The core losses are modeled by equivalent core loss resistances connected to additional windings on the generator's magnetic coupling model. A magnetic circuit is drawn from the magnetic coupling model, and an electrical equivalent circuit of the generator is derived by utilizing a duality between the magnetic and electric circuits. Using this equivalent circuit, the generator's steady‐state performance is theoretically predicted, and the results are verified through experiment. In addition, the power losses during power generation are analyzed quantitatively. The proposed analysis takes into account the nonlinearity of the exciting impedances due to magnetic saturation. © 2000 Scripta Technica, Electr Eng Jpn, 131(2): 51–60, 2000     

Small‐signal stability based on a synchronous generator model with field mutual‐leakage reactance

Power system small‐signal stability studies have been carried out using a synchronous machine model with a field mutual‐leakage reactance called the Canay reactance in the d‐axis equivalent circuit. The influence of the Canay reactance on the effectiveness of a power system stabilizer (PSS) was evaluated by the eigenvalue calculation method. The values of the Canay reactance reported in the literature were also investigated statistically, and an approximate expression applicable to power system stability studies was proposed. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(2): 19–29, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20163     

Development of a 70‐MW‐class quick response excitation superconducting generator

A superconducting generator is expected to be a next‐generation machine due to its many advantages over a conventional generator. Super‐GM has been promoting R&D of 70‐MW‐class superconducting model generators to verify the basic technologies required for the design and manufacture of a 200‐MW‐class superconducting pilot generator. Verification tests of the third model generator, quick response excitation type C generator, were finished in June 1999. The excellent characteristics as a superconducting generator were verified through the series of tests. We report main test results such as “open and short‐circuit test,” “loaded test,” “quick excitation test,” “negative‐phase sequence overcurrent test,” and “sudden short circuit test.” © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(1): 22–29, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10029     

Principle and basic characteristics of linear synchronous motor with half‐wave rectified self excitation

This paper presents the principle and basic characteristics of a novel linear synchronous motor based on “half‐wave rectified self excitation principle.” The field winding is short circuited through a diode and the armature winding consists of conventional three‐phase windings. If the amplitude of the balance three‐phase currents is modulated by an alternating wave with bias frequency, the produced magnetomotive force pulsates at the bias frequency and moves at the synchronous velocity. This pulsating magnetomotive force induces the electromotive force with a bias frequency in the field winding. The field excitation is obtained by rectifying the electromotive force with the diode in the field winding. In this paper, the authors design and build an experimental machine and confirm its basic characteristics. They also deduce the performance equations and investigate the thrust ripple reduction. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(1): 82–90, 2008; Published online in Wiley InterScience ( www. interscience.wiley.com ). DOI 10.1002/eej.20684     

Simple and accurate approaches to implement the complex trans‐conductance suited for time‐domain simulators for small‐signal and large‐signal table‐based models

This paper focuses on the implementation of table‐based models of high‐frequency transistors for time‐domain simulators at microwave and mm‐wave frequencies. In this frequency range, the channel is not capable of responding to the excitation instantaneously therefore, a delay‐time exists between the channel response and the channel excitation. This delay is represented by a complex trans‐conductance in terms of circuit elements. The high‐frequency models of transistors are required to have the implementation of complex trans‐conductance, where the complex part accounts mathematically for the delay‐time between the channel response and the channel excitation. This paper presents simple and accurate approaches to incorporate the complex trans‐conductance in both small‐signal and large‐signal table‐based models for time‐domain simulators (MOS‐AK International Meeting. Eindhoven, Netherlands, April 2008). Implementation approach for each model, small‐signal and large‐signal, is presented in separated sections. In the first step, the delay is realized by the introduction of an ideal transmission line between the channel excitation and the channel response. As transmission lines are not generally suitable for time‐domain simulations, a lumped element equivalent network is introduced in the second step. The latter approach is fully compatible with time‐domain simulators but frequency limitation, determined by the delay‐time value itself, is introduced. Then the implementation of the complex trans‐conductance in large‐signal model is introduced. In terms of large‐signal behavior, delay‐time is important to achieve a non‐quasi static model. Yet again there is limitation in terms of the frequency range that is determined by the delay value itself. The methodology is illustrated on the small‐signal and the large‐signal equivalent circuit of a Multi‐Fin MOSFET transistor. Simulations are carried out by Cadence Spectre and Agilent ADS simulators, and comparisons are carried out between the simulation results and the measurements. Copyright © 2010 John Wiley & Sons, Ltd.     

混合磁路电机的哈密顿建模与控制

针对电机传统控制策略对参数变化敏感等问题,从能量的观点出发,将哈密顿能量系统理论应用于混合磁路电机,将混合磁路电机数学模型表示成了广义耗散哈密顿系统的形式,给出了混合磁路电机的哈密顿能量函数,设计了混合磁路电机的非线性稳定控制器和负载观测器。仿真结果验证了理论分析的正确性和控制律的有效性。     

Identification of the parameters of the high‐frequency equivalent circuit of PM synchronous motor based on genetic algorithm

This paper presents an identification technique of parameters of a high‐frequency equivalent circuit of permanent magnet synchronous motors (PMSM) driven by a PWM inverter. The high‐frequency oscillatory currents such as leakage current to the motor frame (common‐mode current) and high‐frequency oscillatory line current (normal‐mode current) are generated by switching instants of inverter transistors. The parameters of the high‐frequency equivalent circuit of PMSM which can simulate the oscillating current are identified by means of genetic algorithm. It is shown that the high‐frequency equivalent circuit with identified parameters can generate the oscillating current by some simulation results. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(4): 57–66, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20717     

A calculation method of field current of synchronous machines at sudden short‐circuit

The mutual leakage reactance between D‐axis damper and field windings is ignored in conventional D‐axis equivalent circuits. It has been pointed out, however, that the calculated value of the field current differs considerably from the measured value if this reactance is not taken into account. This is due to the difficulty of determining the physically correct damper winding impedance value. A method of determining the equivalent circuit constants using the mutual leakage reactance has been reported previously, where the D‐axis damper winding time constant is measured from the upper and lower envelopes of field current at sudden three‐phase short‐circuit. Yet there are machines for which the upper and lower envelopes of field current are not readily established, and in this case the method is unsatisfactory. The authors describe a method to accurately identify the equivalent circuit constants taking into account the mutual leakage reactance, using a standstill test with a small‐capacity DC power supply (DC decay testing method). The field current at sudden short‐circuit can be simulated accurately using these equivalent circuit constants. The validity of the proposed method is demonstrated by implementation results on two salient‐pole synchronous machines at the same specifications (one with damper winding, the other without). Furthermore, the dependent relation between the armature leakage reactance and mutual leakage reactance, as well as its influence on the calculation of field transient currents, are made clear. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(3): 61–70, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20113     

Design and analysis of power‐CMOS‐gate‐based switched‐capacitor DC–DC converter with step‐down and step‐up modes

A unified multi‐stage power‐CMOS‐transmission‐gate‐based quasi‐switched‐capacitor (QSC) DC–DC converter is proposed to integrate both step‐down and step‐up modes all in one circuit configuration for low‐power applications. In this paper, by using power‐CMOS‐transmission‐gate as a bi‐directional switch, the various topologies for step‐down and step‐up modes can be integrated in the same circuit configuration, and the configuration does not require any inductive elements, so the IC fabrication is promising for realization. In addition, both large‐signal state‐space equation and small‐signal transfer function are derived by state‐space averaging technique, and expressed all in one unified formulation for both modes. Based on the unified model, it is all presented for control design and theoretical analysis, including steady‐state output and power, power efficiency, maximum voltage conversion ratio, maximum power efficiency, maximum output power, output voltage ripple percentage, capacitance selection, closed‐loop control and stability, etc. Finally, a multi‐stage QSC DC–DC converter with step‐down and step‐up modes is made in circuit layout by PSPICE tool, and some topics are discussed, including (1) voltage conversion, output ripple percentage, and power efficiency, (2) output robustness against source noises and (3) regulation capability of converter with loading variation. The simulated results are illustrated to show the efficacy of the unified configuration proposed. Copyright © 2003 John Wiley & Sons, Ltd.     

混合磁路电机结构化建模与控制仿真

研究了混合磁路电机动态数学模型的结构化实现,结构化模型物理意义明确,而且结构简单.是混合磁路电机实用化的重要一步.并利用直接反馈线性化理论(DFL)建立了解耦控制器,将混合磁路电机解耦成三个独立线性子系统.仿真结果表明,基于直接反馈线性化控制设计及结构化模型的混合磁路电机控制系统具有良好的动态性能.     

A General Analytical Method for a Three‐Phase Line‐Start Permanent‐Magnet Synchronous Motor

A line‐start permanent‐magnet synchronous motor (LSPMM) consists of a stator with symmetrical three‐phase armature windings and a salient pole rotor with a permanent magnet for excitation and a starting winding similar to the squirrel‐cage winding of an induction motor. In this paper, a general analytical method based on tensor analysis is proposed for practical performance calculation of a three‐phase LSPMM. The general equation for the currents of the three‐phase LSPMM is derived from the transient impedance tensor expressed in polyphase symmetry axes, and the general equation for vibratory and nonvibratory torques is derived from the current equation. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 185(4): 60–68, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21284     

考虑转子谐波电流影响后双馈电机电磁功率的分析与计算

有不少文章研究了双馈电机的稳态运行性能，但在研究其性能时考虑谐波电流影响的却较少。该文从该类电机的基本电磁关系出发，提出了基波和谐波的等效电路，给出了谐波电路中参数的计算方法。导出了基波电磁功率、稳定谐波电磁功率及脉动谐波电磁功率的计算公式。文章最后以一个实际的绕线型感应电机用交直交电压型逆变器供给励磁的双馈电机为例，计算了主要谐波的稳定和脉动的电磁功率以及电机总的电磁功率。结果表明，该文给出的分析与计算方法是有效的。     

Dynamics of charge‐pump phase‐locked loops

Certain problems in the existing treatment of the stability of charge‐pump phase‐locked loops are identified and addressed in this work. New results concerning the instability, stability, and asymptotic stability of charge‐pump phase‐locked loops are obtained by means of Lyapunov's direct and indirect methods. Closer consideration of the local dynamics provides further insight into the system's patterns of behavior. In particular, the influence of circuit parameters on the nature of the steady‐state orbits is investigated. Copyright © 2012 John Wiley & Sons, Ltd.     

Parameter identification of simplified common‐mode equivalent circuit for inverter‐fed motor drive systems by applying computer‐aided optimization software

This paper deals with common‐mode (CM) electromagnetic interference (EMI) in an inverter‐fed motor drive system. A simplified CM equivalent circuit including π‐type equivalent circuit for the motor winding is proposed by using the waveform of the common‐mode current flowing in the ground conductor. Moreover, a parameter identification method applying the computer‐aided software modeFRONTIER is proposed to decide objectively the circuit parameters of the proposed simplified equivalent circuit. Validity and effectiveness of the proposed equivalent circuit are confirmed by comparing the measured impedance characteristics with the calculated ones. Finally, the possibility of a nonlinear phenomenon is discussed in this system. It is shown that the accuracy of simulation result can be improved by introducing the nonlinear element. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Three‐stage multiphase‐switched‐capacitor boost DC‐AC inverter

A closed‐loop scheme of a three‐stage multiphase‐switched‐capacitor boost DC‐AC inverter (MPSCI) is proposed by combining the multiphase operation and sinusoidal‐pulse‐width‐modulation (SPWM) control for low‐power step‐up DC‐AC conversion and regulation. In this MPSCI, the power unit contains two parts: MPSC booster (front) and H‐bridge (rear). The MPSC booster is suggested for an inductor‐less step‐up DC‐DC conversion, where three voltage doublers in series are controlled with multiphase operation for boosting voltage gain up to 2³ = 8 at most. The H‐bridge is employed for DC‐AC inversion, where four solid‐state switches in H‐connection are controlled with SPWM to obtain a sinusoidal AC output. In addition, SPWM is adopted for enhancing output regulation not only to compensate the dynamic error, but also to reinforce robustness to source/loading variation. The relevant theoretical analysis and design include: MPSCI model, steady‐state/dynamic analysis, voltage conversion ratio, power efficiency, stability, capacitance selection, total harmonic distortion (THD), output filter, and closed‐loop control design. Finally, the closed‐loop MPSCI is simulated, and the hardware circuit is implemented and tested. All the results are illustrated to show the efficacy of the proposed scheme. Copyright © 2011 John Wiley & Sons, Ltd.     

Exact sampled‐data analysis of quasi‐resonant converters with finite filter inductance and capacitance

Previous models of quasi‐resonant converters generally use averaging and assume infinite filter inductance and capacitance to reduce circuit complexity, but at the expense of accuracy. In this paper, exact sampled‐data modelling is used. A general block diagram model applicable to various topologies of quasi‐resonant converters is proposed. Large‐signal analysis, steady‐state analysis and small‐signal analysis are all studied. They agree closely with the experimental results in the literature. Compared with the averaging approach, the sampled‐data approach is more systematic and accurate. Copyright © 2001 John Wiley & Sons, Ltd.