Method for Diffusing Carrier Noise under Zero‐Speed Condition using a Zero‐Sequence Voltage

In this paper, a technique is proposed to reduce the carrier noise of pulse width modulation (PWM) inverters for a permanent magnet motor drive. The carrier noise is generated by the motor and the reactor driven by the inverter and affected by the switching frequency. When a motor rotates and drives a machine, the carrier noise is hidden by the machine noise. However, when the motor speed is approximately zero, the carrier noise becomes dominant and raucous. The typical method to reduce the noise employs a switching frequency higher than the audible frequency of human hearing. However, the increase in switching frequency results in the inverter suffering a higher switching loss and lower efficiency. In particular, when the permanent magnet motor operates at approximately zero‐speed and full‐load, for example, in the hill‐start conditions of electric vehicles and the start and stop conditions of elevators, the current flows in specific power devices and the switching loss further increases. The proposed technique uses a zero‐sequence voltage, which is generated randomly with the M‐sequence signal, and diffuses the frequency components of the ripple contained in the current. The technique is able to reduce the noise without increasing the switching frequency of the inverter when the motor speed is almost zero. Simulation and experimental results show that the proposed technique can diffuse the carrier noise and the cycle of the M‐sequence signal changes the diffusion effect of the carrier noise.     

一种新型无刷直流电机谐振极软开关逆变器

永磁无刷直流电机具有高功率密度、高转矩/电流比和控制简单等优势,得到了广泛应用。然而,无刷直流电机通常采用硬开关逆变器驱动,硬开关逆变器的系统效率较低,散热器的体积和重量较大,限制了大功率无刷直流电机驱动系统功率密度和性能的进一步提升。针对硬开关逆变器问题,提出了一种无刷直流电机专用的谐振极软开关电压源逆变器。通过在传统硬开关逆变器的三相输出端添加辅助谐振网络,实现了逆变桥主开关器件的零电压(ZVS)开关动作,辅助双向开关在零电流开关(ZCS)条件开通和关断。针对新型软开关逆变器,提出了一种新的脉宽调制(PWM)控制策略——TPWM TON,逆变桥上下侧开关器件轮流进行PWM调制,保持了直流母线中点电位的平衡,且使主开关和辅助开关的开关频率降到PWM调制频率的一半。对提出的软开关逆变器进行了实验研究,实验结果验证了电路结构、理论分析和控制策略的正确性与可行性。     

Newly proposed hybrid resonant commutation bridge‐leg link snubber‐assisted three‐phase ZVZCS‐PWM soft‐switching inverter

This paper presents the newly proposed hybrid resonant commutation bridge‐leg link (HRCB) snubber circuit which can achieve zero voltage and zero current soft‐switching commutation for single‐phase and three‐phase voltage source‐type inverter, along with its unique features and operation principle. The circuit parameter design approach for the HRCB snubber circuit and the determination estimating scheme of the gate pulse timing processing which is more suitable and acceptable for single‐phase and space voltage vector modulated three‐phase voltage source inverter using the HRCB snubber circuit are described in this paper. In particular, the three‐phase voltage source soft‐switching inverter associated with the proposed HRCB circuits are evaluated and discussed from simulation and experimental viewpoints. The practical effectiveness of the HRCB snubber‐assisted three‐phase voltage source soft‐switching inverter using IGBT power modules which is based on the instantaneous space voltage vector modulation is clarified on the output voltage waveform, actual efficiency of electromagnetic noise in comparison with three‐phase voltage source‐type conventional hard‐switching inverter. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 75–84, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20111     

一种基于开关次数最小的含零电压矢量永磁同步电机直接转矩控制开关表

介绍了永磁同步电机(PMSM)直接转矩控制(DTC)理论,研究了零电压矢量的作用。基于开关次数最小提出了选择零电压矢量的策略,给出了一种新型含零电压矢量开关表。仿真结果表明使用新型开关表PMSM DTC系统能正常驱动。与传统开关表相比,使用新型开关表DTC系统开关次数降低了近56%,进而降低了开关损耗。     

双级矩阵变换器驱动异步电机直接转矩控制

在深入分析双级矩阵变换器整流级调制算法和逆变级直接转矩控制策略的基础上,提出了采用双级矩阵变换器驱动异步电机直接转矩控制的策略。换流方式采用零电流换流的思想,即整流级换流前后,在逆变级插入零开关状态,可以保证整流级的零电流换流。此控制策略结合了双级矩阵变换器和直接转矩控制的优点,功率因数可调且具有良好的动静态性能。仿真结果验证了该控制策略的可行性和有效性,表明该策略具有与直流调速系统相媲美的调速性能。     

新型软开关三相并网逆变器

提出了一种新型软开关三相逆变器,可以只采用一个辅助开关实现所有开关的零电压开通(ZVS),并抑制二极管反向恢复。逆变器的主开关和辅助开关具有相同且固定的开关频率,主开关和辅助开关电压应力均等于直流母线电压。分析了软开关三相桥式并网逆变器的软开关过程,研制了20 kW试验样机并完成了试验验证。     

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     

基于模糊控制的永磁同步电机直接转矩控制

设计了基于模糊控制的永磁同步电机(PMSM)直接转矩控制(DTC)系统,采用模糊控制器取代了传统DTC系统中的磁链和转矩滞环比较器及开关表。仿真结果表明:模糊控制PMSM DTC系统运行良好,可实现四象限运行,与传统开关表相比,可有效减小转矩脉动和平均开关频率。研究了转矩误差论域和零电压矢量对模糊控制性能的影响,并基于转矩角对电压矢量作用的影响规律,提出了考虑转矩角的PMSM模糊直接转矩控制。仿真结果表明:在转矩角较大时,考虑转矩角的PMSM模糊DTC系统可有效减小转矩和磁链脉动,改善控制性能。     

Analysis and implementation of a high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter

A high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter with ripple‐free input current is presented. In the presented converter, the ripple‐free boost cell provides ripple‐free input current and zero‐voltage switching of power switches. The resonant flyback cell provides zero‐voltage switching of power switches and zero‐current switching of the output diode. Also, it has a simple output stage. The proposed converter achieves high efficiency because of the reduction of the switching losses of the power switches and the output diode. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed and its experimental results are presented for validation. Copyright © 2011 John Wiley & Sons, Ltd.     

Novel current‐source multilevel inverter driven by single gate drive power supply

This paper proposes a novel current‐source multilevel inverter, which is based on a current‐source half‐bridge topology. Multilevel inverters are effective for reducing harmonic distortion in the output voltage and the output current. However, the multilevel inverters require many gate drive power supplies to drive switching devices. The gate drive circuits using a bootstrap circuit and a pulse transformer can reduce the number of the gate drive power supplies, but the pulse width of the output PWM waveform is limited. Furthermore, high‐speed power switching devices are indispensable to create a high‐frequency power converter, but various problems, such as high‐frequency noise, arise due to the high dv/dt rate, especially in high‐side switching devices. The proposed current‐source multilevel inverter is composed of a common emitter topology for all switching devices. Therefore, it is possible to operate it with a single power supply for the gate drive circuit, which allows stabilizing the potential level of all the drive circuits. In this paper, the effectiveness of the proposed circuit is verified through experimental results. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(2): 88–95, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20475     

Influence of Inverter Output Filter on Maximum Torque and Speed of PMSM Drives

This paper deals with the maximum torque and speed of permanent-magnet synchronous motor (PMSM) drives when the inverter output voltage is filtered by an LC filter with a cutoff frequency well below the switching frequency. According to steady-state analysis, the filter affects the performance of the motor drive, especially at high speeds. The stator current is not equal to the inverter current, and due to the inverter current and inverter voltage limits, the torque-maximizing stator current locus differs from that of a drive without the filter. A field-weakening method is proposed for PMSM drives with an inverter output filter. The method is implemented and tested in a 2.2-kW PMSM drive. The experimental results agree well with the analysis, and validate the high-speed performance of the proposed field-weakening method.      

基于自适应FIR算法的交流伺服系统前馈控制

永磁同步电机(PMSM)交流伺服控制系统中由于电子器件的开关引起相电流非正弦变化,经坐标变换得到的交直轴电流含有谐波成分,引起电流环振荡及电磁转矩脉动。在分析相电流与交直轴电流高次谐波关系,以及交直轴电流高次谐波对电磁转矩影响的基础上,提出了一种基于自适应FIR滤波器的交流伺服系统前馈控制策略,并在该方法的基础上提出了变步长因子算法,根据误差值改变步长因子,在提高滤波器收敛速度的同时减小超调。该算法与传统的一阶低通滤波器相比,相位不滞后,灵敏度更高,且系统稳定。改进后的控制策略有效地降低交直轴电流谐波,抑制电流环振荡及电磁转矩脉动,提高PMSM交流伺服控制系统稳定性及动态响应。通过仿真与试验证明了该方法的可行性。     

新型无刷直流电动机专用谐振极逆变器研究

无刷直流电动机通常采用硬开关逆变器驱动.硬开关逆变器的系统效率较低,散热器的体积和重量较大,限制了无刷直流电动机驱动系统功率密度和性能的进一步提升.针对硬开关逆变器问题,提出了一种无刷直流电动机驱动系统专用的谐振极软开关电压源逆变器.通过在传统硬开关逆变器三个输出端和直流母线之间添加辅助谐振单元,实现了逆变桥主开关器件的PWM软开关动作.谐振控制开关零电流开关条件开通,零电压开关条件关断.对提出的新型谐振极逆变器进行了数学分析和仿真研究;仿真结果验证了电路结构和理论分析的正确性与可行性.     

基于双级矩阵变换器的直接转矩控制系统

研究了基于双级矩阵变换器的异步电机直接转矩控制策略。传统的直接转矩控制(Direct Torque Control,简称DTC)算法直接施加在双级矩阵变换器的逆变级,而在整流级使用空间矢量调制的方法。在此设计了一种特殊的换流策略,即在整流级换流前后,在逆变级插入零开关状态,保证了整流级的零电流换流特性。该方法结合了DTC和双级矩阵变换器的优点。设计并实现了实验样机系统,实验结果验证了该控制策略的可行性和有效性。     

Feasible enhancement of a three‐phase soft‐switching inverter with an auxiliary resonant DC link snubber

The purpose of this paper is to improve power conversion efficiency of a three‐phase voltage source type soft‐switching inverter with a single auxiliary resonant DC link (ARDCL) snubber. First, the operating principle of an ARDCL snubber discussed here is described. Second, this paper proposes an effective pulse pattern generation method of the zero voltage space vector of the three‐phase soft‐switching inverter using IGBTs or power modules that can reduce power losses in the ARDCL snubber treated here. In particular, a zero voltage holding interval in the DC rail busline of this three‐phase soft‐switching inverter is to be regulated according to the generation method of the zero voltage space vector. Third, the maximum modulation depth M_max under the condition of correction of the instantaneous voltage space vector can be improved by using a new zero voltage space vector generation method. Finally, the feasible experimental results of this inverter are obtained confirming the operating characteristics such as power conversion actual efficiency, as well as conventional efficiency THD and RMS value of the balanced three‐phase output voltage for an experimentally built three‐phase voltage source type soft‐switching pulse modulated inverter using the latest IGBT modules and evaluated from the standpoint of practical applications in industry UPS and new energy systems. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 89–99, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10234     

一种高效率软开关三相并网逆变器

提出一种只采用一个辅助开关,即能实现所有开关的零电压开通,并能抑制二极管反向恢复的高效率软开关三相并网逆变器.逆变器可以采用空间矢量调制(SVM)策略,主开关和辅助开关具有相同且固定的开关频率.分析了软开关三相并网逆变器的开关过程,给出了谐振参数设计步骤.研制了20 kW实验样机并完成了实验验证,实验结果表明,并网逆变...     

一种新型有源箝位软开关三相并网逆变器

提出了一种新型软开关三相并网逆变器,通过在逆变器直流侧增加1个由辅助开关、谐振电感和箝位电容组成的谐振支路,可以实现逆变器主开关和辅助开关的零电压开通,同时开关反并联二极管反向恢复电流得到抑制。逆变器主开关和辅助开关具有相同且固定的开关频率,主开关和辅助开关电压应力均等于逆变器直流母线电压。对逆变器的调制策略、软开关谐振过程进行了研究,分析了逆变器谐振参数的设计方法,设计了20 kW实验样机并完成了实验验证。     

Characteristics of PM synchronous motor drives with a trapezoidal EMF

A permanent magnet synchronous motor (PMSM) with nonsinusoidal electromotive force (EMF) generates torque ripple even if the sinusoidal PWM inverter drives the PMSM. A new modified trapezoidal modulating signal for PWM inverter suitable for PMSM drive with nonsinusoidal EMF is proposed in this paper. A new modulating signal for the PMSM drive is determined by the condition of reducing torque ripple of the motor with various trapezoidal EMF. When the PWM inverter using modified trapezoidal modulating signal drives the PMSM having a nonsinusoidal EMF, the torque ripple of the motor can be reduced, the DC link voltage utilization is improved, and reduction of switching loss can be obtained. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 62–71, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20441     

用于无刷直流电机驱动的谐振极软开关逆变器

用硬开关逆变器来驱动无刷直流电机会产生逆变器的开关损耗大和运行效率低的问题。为降低开关损耗,提出一种用于无刷直流电机驱动的新型谐振极软开关逆变器的拓扑结构,通过在传统硬开关逆变器的三相输出端添加辅助谐振电路,利用辅助电路中的高频变压器的等效电感与主开关并联的缓冲电容之间的谐振,实现逆变器主开关器件的零电压开关和辅助开关器件的零电流开关。依据不同工作模式下的等效电路图,分析了电路的换流过程和设计规则,并建立起了辅助谐振电路损耗的数学模型,讨论了谐振参数对辅助电路损耗的影响。制作了1台实验样机,实验结果表明逆变器的主开关和辅助开关都实现了软开关。该谐振极软开关逆变器能有效改善效率,降低开关损耗。     

High‐efficiency,low‐torque ripple control of a permanent magnet synchronous motor based on current tracking vector of electromotive force

Since ordinary magnetic field poles of a PM (permanent magnet) motor generate higher harmonic flux, sinusoidal current will cause torque ripple. This is usually removed by short pitch winding, skew slot method, and so on. These methods have a drawback in terms of lower efficiency. Recently, new current control methods have been proposed to realize zero‐torque ripple and high‐efficiency drive at the same time. However, because the optimized reference current waveform obtained by these methods includes zero phase component, normal three‐phase full bridge inverter and d–q coordinate control method cannot be used. This paper proposes a new current control method that can achieve zero‐torque ripple and maximum efficiency by using a normal three‐phase inverter. The three‐phase optimum current can be derived by satisfying the following conditions: (1) the direction of the current resultant vector always agrees with that of the electromotive force resultant vector, and (2) the scalar product of the two vectors is held constant. By means of modifying the coordinate transformation angle, this method can also make it possible to compensate torque pulsation error with maximum efficiency using general d–q coordinate control method. The proposed method has been verified by experiments. © 2001 Scripta Technica, Electr Eng Jpn, 136(1): 57–64, 2001