AC Motor Drives With a Reduced Number of Switches and Boost Inductors

This paper presents eight three-phase ac motor-drive configurations that operate with a reduced number of switches and boost inductors. Four of the configurations are single-motor drives, and four of the configurations are double-motor drives. The drives provide both bidirectional power flow and power-factor control. This paper presents the analysis and control strategy of the systems, including current control and pulsewidth-modulation strategy. In spite of using a reduced number of components, the dc-link voltage and the machine currents of some of the proposed configurations are not much larger than the equivalent values of the conventional configurations. These drive systems are suitable for applications where the size of the system is a critical factor. The experimental results demonstrate the feasibility of the proposed topologies     

Parallel single-phase ac–dc–ac shared-leg converters: Modelling,control and analysis

Reversible single-phase to single-phase dc-link converters are proposed and analyzed in this paper. They are composed of paralleled rectifiers and inverters sharing one or two legs with one or two dc-links. Modelling and a control strategy of the systems including circulating currents are developed. Compared to the conventional single-phase to single-phase dc-link converter, the proposed topologies permit to reduce: (i) the current and power ratings of the power switches, (ii) the harmonic distortion, and (iii) the dc-link capacitor losses. Additionally, the semiconductor losses of the proposed converters are smaller than that of the conventional one. Simulated and experimental results are also presented to demonstrate the viability of the proposed circuits.     

The windmill topology

A widely used 18-pulse clean power converter with windmill transformer topology is presented and analyzed. It provides a more economical solution to achieve harmonicmitigation in electric power systems when compared with some of the earlier methods. With the proliferation of nonlinear loads in industrial power systems, the advent of IEEE 519-1992 [1], and the increasing demand by utilities for power factor improvement, the specification of harmonic mitigation has become common [2], [3]. In the past 14 years, several patented 18-pulse converter methods have been accepted in the marketplace and are successfully applied in a variety of practical applications such as water management, oil field installations, etc., where adjustable speed drive (ASD) and harmonic mitigation are required. A threeto nine-phase unity-gain autotransformer topology with a ±20° phase shift between output voltages is first proposed in [4]. The step-up and step-down 18-pulse autotransformer topologies with a 40° phase shift between the output voltages are discussed in [5]?[9]. The winding current looping and sharing problems in early days have already been solved [10]. The challenging design problem becomes one of economics [11].     

脉冲阻塞式斩波交-交变频技术

为了改变传统交-交变频技术功率因数低,功率器件多的状况,发挥无中间直流环节,功率双向流动和超低速传动等优势,针对节电传动设计了一种低成本装置,提出将交-交斩波调压器变性为交-交斩波变频器的构想,用周期性阻塞式脉冲控制取代了连续脉冲控制,并用等脉宽和SPWM变脉宽两种规律实现了该构想。文中推导了设定工作频率下控制参数的关系式,讨论了最少器件的拓扑,并给出了单管变频器的典型实验波形。最后,分析了该技术的应用前景,并建议采用压频比协调变频调速与单独变压调速的分段复合开环控制策略,实现电机系统的低成本简易节电。     

多电平变换器拓扑关系及新型拓扑

多电平变换器在高压大容量电力电子及交流调速系统中已经得到了广泛应用.本文对多电平发展的历程进行了回顾,分析了多电平拓扑结构之间的联系,提出了通用多电平拓扑简化成其他多电平拓扑所要遵循的规律.在此基础上,提出了两种新的拓扑结构,并对其工作原理和控制方法进行了仿真研究.仿真结果验证了所提出的拓扑和控制方法的可行性,也进一步...     

大功率中压交流传动

对1～100 MW范围内的大功率中压变频传动逆变器的应用情况和全球市场进行了综述分析.对已有的功率半导体器件和逆变器拓扑电路,根据他们的不同特点进行了介绍,并对其优缺点进行比较;同时对大功率交流传动应用的主要特点以及与此相适合的变频器类型进行了讨论和选择.最后,对功率半导体器件、变换器类型和电机的发展趋势进行了展望.     

Power converter control based on neural and fuzzy methods

The new power converter control approaches based on neural network techniques and fuzzy logic theorems are briefly reviewed and discussed in this paper. Current-controlled voltage source inverters offer substantial advantages in improving motor system dynamics for high-performance AC drive systems. The controller switches follow a set of reference current waveforms. Fixed-band and sinusoidal-band hysteresis current controllers have been studied. The first part of this paper develops neural network and fuzzy logic based current-controlled voltage source inverters. The models and learning techniques have been investigated by simulation. The implementation of neural networks is described and simulation results are presented. In the second part of this paper, the new UPS (uninterruptible power supply) with fuzzy logic compensator is proposed. The proposed fuzzy logic compensator is used to prevent voltage drop from nonlinear loads. The total harmonic distortion (THD) of the proposed scheme is better than that of conventional deadbeat control methods for linear and nonlinear loads. The applications of fuzzy and neural network control to DC-DC converters operating at finite switching frequency are studied in the third part of this paper. The fuzzy logic and neural network controller for unity power factor rectifiers, half-bridge DC-DC ZVZCS converters, DC motor drives, induction motor drives and permanent-magnet motor drives are also discussed. Some simulations are presented in this paper.     

Analysis of multiloop control strategies for LC/CL/LCL-filtered voltage-source and current-source inverters

Multiloop control strategies have commonly been used to control power inverters of both the voltage-source and current-source topologies for power conversion applications including uninterruptible power supplies and utility interfaces for distributed power generation. However, these control strategies tend to be developed and comparatively evaluated for a particular application, with strategies for other applications presented as independent new developments. This paper presents a generalized analysis of different multiloop control approaches using alternative feedback control variables for several popularly adopted system configurations, highlighting similarities and identifying a generalized optimal control-variable selection criterion that is applicable across most multiloop-controlled inverter systems. The generality of the presented optimal variable selection criterion has been verified through the close similarities between the time-domain waveforms of the different inverter systems simulated in MATLAB Simulink and implemented experimentally in the laboratory.     

AC motor drive systems with a reduced-switch-count converter

This paper presents two reduced-switch-count AC drive systems. One of the configurations was conceived to operate with a two-phase motor and the other one with a three-phase motor. The drive systems provide both bidirectional power flow and power factor control. Pulsewidth modulation techniques for the converter control are discussed. Experimental results are presented.     

中大功率单级功率因数校正变换器中的偏磁分析及其数字化抑制技术

单级型功率因数校正变换器(power factor corrector,PFC)由于具有功率密度高和电气隔离等特点,在工业界某些应用场合得到应用,然而,用于该拓扑的变压器很容易饱和。基于隔离型全桥拓扑,分析单级型PFC变换器中变压器偏磁产生机理,并推导出每个工频周期内最大的理论偏磁值。对传统偏磁抑制方案进行分析,阐述数字控制本身对偏磁抑制的原理,提出一种能对偏磁有效抑制的数字补偿方案。新型数字控制方案能够避免传统方案所带来的诸如占空比减小和效率降低等问题,且不会增加电路复杂度。通过额定输出功率为5.1 kW的样机验证了所提出的偏磁抑制方案的有效性和优越性。样机满载功率因数达到0.994,效率超过92%。     

Application-Oriented Low-Side Gate Drivers

This paper presents three types of low-side gate drivers to drive n-channel power metal-oxide-semiconductor field-effect transistors (MOSFETs). Most important of all, each gate driver has a single positive-voltage source fed, and any one of these three types is used according to applications. In addition, the main purpose of the proposed gate drivers is to reduce the losses created from power MOSFETs. In this paper, the detailed operating principles of the proposed gate drivers are illustrated, along with some experimental results provided to verify the feasibility of the proposed topologies.     

Theory and design of a 30-hp matrix converter

The control strategy and hardware design for a 30 hp matrix power converter (nine-switch forced-commutated cycloconverter) that was developed for high-bandwidth four-quadrant motor drive applications is described. The new switching technique ensures very low distortion of the input currents with unity fundamental displacement factor. Experimental results are presented     

无共模电压SVPWM多桥臂逆变器的拓扑结构演化与电机性能研究

三相开放式绕组永磁同步电动机(PMSM)可采用单电源双逆变器供电,与传统单逆变器供电的PMSM相比具有可选电压矢量多及控制方法灵活等优点,有利于改善电机驱动性能,但逆变器桥臂数量较多,硬件结构复杂。为此,针对无共模电压空间矢量脉宽调制(SVPWM)控制方法,对单电源双逆变器(即六桥臂)驱动拓扑结构进行演化,逐步减少桥臂数量,并对比分析各演化结构驱动下的电机性能。各演化结构虽然引入了额外的零序电流通路,但在无共模电压SVPWM控制下没有零序电压激励,因此并无零序电流产生,故拓扑结构的演化并不影响电机控制性能。该拓扑结构演化不仅为逆变器与电机绕组的选型设计提供参考,还揭示了无共模电压SVPWM的本质特性。     

Novel Two-Switch-Based Switched Reluctance Motor Drive for Low-Cost High-Volume Applications

This paper presents a low-cost energy-efficient variable-speed drive for high-volume applications, such as home appliances, fans, and hand tools. A new low-cost power converter is proposed, and the drive system is realized using a two-phase switched reluctance motor and the proposed converter. The motor is capable of self-starting at any rotor position and four-quadrant operation. The converter is unique in that it has two capacitors for the energization of each phase and uses the main phase winding as energy storage for the secondary capacitor C2. The converter employs a single-switch-per-phase configuration, hence requiring only two controllable switching devices in total. The converter is inherently suited for two-phase motors having asymmetric stator phases to realize self-starting and speed reversal. Simple starting and C2 voltage control schemes are presented. This paper describes the analysis, modeling, control algorithm, and design considerations for a prototype drive system. Experimental verification and correlation with simulation results are presented. The proposed drive system offers a low-cost brushless variable-speed drive that is a potential alternative for conventional brush-commutator motors in high-volume applications.     

静止无功发生器在高压电力系统中的应用

静止无功发生器是柔性交流输电系统中重要的电力电子装置 ,它集中了电力电子和微电子技术的优点 ,是高压电力系统稳定电压和提高功率因数的理想装置 ,具有良好的应用前景。介绍了静止无功发生器工作原理和控制方法 ,探讨了它在高压电力系统中应用的相关问题 ,包括消除静止无功发生器自身谐波的多重化技术及曲折变压器联接方式。模拟实验结果验证了所述控制方法的可行性     

航空用高可靠永磁容错电机及其驱动系统的研究现状与发展

随着多电飞机的飞速发展,对飞机电作动系统的要求也越来越高,除了要满足特定功能外,还必须具备高可靠性和强容错性,因此容错电机驱动系统得到了越来越多的关注。本文针对当前研究较多、关注较高、极具前景的永磁容错电机及其驱动系统,分别对现有永磁容错电机及其驱动系统的研究现状、永磁容错电机驱动系统容错控制策略的研究现状进行了详细介绍与分析,并从具有容错能力方面、所需独立电源数量方面、所需功率开关管数量方面、整体容量功率比方面以及容错控制策略方面对现有常见的各种航空用永磁容错电机驱动系统进行了综合性能的对比分析。最后对航空用高可靠永磁容错电机及其驱动系统未来的发展进行了讨论与展望     

Optimal power control strategies for neutral point clamped (NPC)inverter topology

A programmed pulsewidth modulation (PWM) technique for selectively eliminating several lower-order harmonics at the output of a neutral point clamped (NPC) inverter topology is investigated. The switching function approach is utilized to derive relevant analytical expressions for input/output variables. A thorough evaluation of the NPC inverter topology based on the switching function approach is described. Optimal power control strategies for an NPC inverter employing programmed PWM patterns are proposed. For a constant-frequency variable-voltage NPC inverter power supply, the proposed strategy is to maintain a minimum specified total harmonic distortion employing a low-output impedance filter. In the case of an NPC inverter powering an AC motor drive, the proposed strategy is to maintain a minimum specified harmonic current factor. The proposed power control strategies are achieved without substantial increase in inverter switching frequency and are therefore suitable for high-power applications employing gate-turn-off-thyristor (GTO) type devices     

Electromagnetic gate-inductor electric drives with open-loop control systems

A simplified transducer-free realization of electromagnetic gate-inductor electric drives with openloop control systems is proposed with prospective applications for the majority of rotary-, linear-, and alternatemotion-type industrial mechanisms. A functional scheme of the control system for the electric drive under consideration is given. A simplified calculation of the basic parameters of the rotary motion electric drive is presented. The advantages of reducer-free electric drive constructions are shown.     

Ultrasonic motors: Their models, drives, controls and applications

In the last decades piezoelectrically driven ultrasonic motors have become alternative actuators to the conventional electromagnetic motors especially for precise and accurate servo positioning applications. Different types of ultrasonic motors have been constructed and manufactured. Several drive systems have been designed, implemented and proposed for these motors. A variety of control techniques have been applied to them. The research given in this study covers bases of the ultrasonic motors. Theoretical background, modeling, drive systems, control techniques and applications of the ultrasonic motors have been introduced. Firstly, the general overview has been given. Then, modeling studies focused on performance estimation and analysis of ultrasonic motors have been examined. Afterwards, drive systems and control techniques of ultrasonic motors have been investigated. Furthermore, an example drive and control system has been presented. This drive system has been designed as to be controlled digitally. In addition, the important industrial and research applications of these motors have been included. The presented study has been arranged as a review of ultrasonic motors. The important points of specifications, models, drive systems and control methods of the ultrasonic motors have been emphasized.