CN100440713C - A two-phase PWM modulation method for reducing common-mode voltage - Google Patents

A two-phase PWM modulation method for reducing common-mode voltage Download PDF

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CN100440713C
CN100440713C CNB2006101655913A CN200610165591A CN100440713C CN 100440713 C CN100440713 C CN 100440713C CN B2006101655913 A CNB2006101655913 A CN B2006101655913A CN 200610165591 A CN200610165591 A CN 200610165591A CN 100440713 C CN100440713 C CN 100440713C
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CN101005244A (en
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陆海峰
瞿文龙
樊杨
程小猛
张星
伍理勋
蒋时军
陈建明
王征宇
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ZHUZHOU INST OF POWER LOCOMOTIVE CHINA NANCHE GROUP
Tsinghua University
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Tsinghua University
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Abstract

The invention discloses PWM modulation technical area by using inverter in three-phase voltage type to control operation of three-phase AC motor. Characters are that three adjacent effective voltage vectors are used to synthesize target vector. The said 'adjacent' means that only one action of switch device is needed to switch from any one state to other state. Comparing with traditional PWM method, the invention avoids using zero vector so as to reduce common mode voltage to 1/3 voltage of general PWM method. The invention also reduces action number of times of switch device so as to solve induced issue of switching loss and heat.

Description

一种减小共模电压的两相PWM调制方法 A two-phase PWM modulation method for reducing common-mode voltage

技术领域 technical field

本发明涉及一种使用三相电压型逆变器控制三相交流电动机运行的两相调制技术。The invention relates to a two-phase modulation technology for controlling the operation of a three-phase AC motor by using a three-phase voltage type inverter.

背景技术 Background technique

脉宽调制(pulse width modulation,PWM)技术特别是空间矢量PWM(space vector pulsewidthmodulation,SVPWM)技术近年来在电力电子与电力传动中得到了广泛应用。Pulse width modulation (PWM) technology, especially space vector PWM (space vector pulse width modulation, SVPWM) technology has been widely used in power electronics and power transmission in recent years.

在三相PWM技术中,如果每个PWM周期中三相开关器件均需要动作,称之为三相调制技术,例如传统的正弦PWM技术,再如普通七段法SVPWM均属此类;如果每个PWM周期中只有两相开关器件动作,另外一相保持上桥臂(或下桥臂)导通,则称之为两相调制技术,也有文献中称之为母线箝位PWM或者不连续调制技术,普通五段法PWM则属此类。In the three-phase PWM technology, if the three-phase switching devices need to act in each PWM cycle, it is called a three-phase modulation technology, such as the traditional sinusoidal PWM technology, and the ordinary seven-segment method SVPWM belongs to this category; if every In a PWM cycle, only two-phase switching devices operate, and the other phase keeps the upper bridge arm (or lower bridge arm) conducting, which is called two-phase modulation technology, and it is also called bus clamp PWM or discontinuous modulation in literature. Technology, the common five-stage method PWM belongs to this category.

对于图1所示的三相电压型逆变器-交流电机系统,如果以0、1表示逆变器每相桥臂状态(1表示上桥臂开关器件导通,0为下桥臂开关器件导通),则逆变器的三相开关状态可用二进制数表示为000~111,共8种状态。如果将每种开关状态对应的逆变器输出电压在两维坐标系(静止αβ坐标系)中以矢量表示,则8个开关状态对应着8个基本的空间电压矢量,如图2所示,其中V0和V7重合于原点。For the three-phase voltage type inverter-AC motor system shown in Figure 1, if 0 and 1 are used to indicate the status of each phase of the inverter bridge arm (1 indicates that the switching device of the upper bridge arm is turned on, and 0 indicates that the switching device of the lower bridge arm conduction), then the three-phase switch state of the inverter can be represented by binary numbers as 000~111, a total of 8 states. If the inverter output voltage corresponding to each switch state is expressed as a vector in a two-dimensional coordinate system (stationary αβ coordinate system), then the 8 switch states correspond to 8 basic space voltage vectors, as shown in Figure 2, Where V 0 and V 7 coincide at the origin.

大多数情况下,控制器给出电压指令不能直接由单一矢量来得到。在空间矢量PWM技术中,以电压指令(也以矢量表示为Vref)两侧的两个基本电压矢量按照平均效果等效的原理来合成目标矢量Vref。以图3为例,当希望输出的参考电压矢量Vref在图示位置时,以V4和V6来合成Vref。即在一个PWM周期Tpwm内,V4和V6各作用一段时间T1、T2,使其平均效果相当于Vref作用Tpwm时间所产生的效果:In most cases, the voltage command given by the controller cannot be obtained directly from a single vector. In the space vector PWM technology, the target vector V ref is synthesized by two basic voltage vectors on both sides of the voltage command (also expressed as V ref in vector) according to the principle of equivalent average effect. Taking FIG. 3 as an example, when the desired output reference voltage vector V ref is at the position shown in the figure, V ref is synthesized with V 4 and V 6 . That is, in a PWM cycle T pwm , V 4 and V 6 act for a period of time T 1 and T 2 respectively, so that the average effect is equivalent to the effect produced by V ref acting on T pwm time:

TpwmVref=T1V4+T2V6                (1)T pwm V ref =T 1 V 4 +T 2 V 6 (1)

如果T1+T2<Tpwm,则在其余的时间内发零矢量来补齐。将上式两边同除以Tpwm,以占空比的形式表示为If T 1 +T 2 <T pwm , send zero vectors to make up for the rest of the time. Divide both sides of the above formula by T pwm , and express it in the form of duty cycle as

Vref=k1V4+k2V6+k00                (2)V ref =k 1 V 4 +k 2 V 6 +k 0 0 (2)

其中k1+k2+k0=1。这里的0表示零矢量,可以选择V0(对应000状态)或者V7(对应111状态),如传统五段法PWM;也可以在一个PWM周期内同时使用V0和V7,如传统七段法PWM。Where k 1 +k 2 +k 0 =1. Here 0 means zero vector, you can choose V 0 (corresponding to 000 state) or V 7 (corresponding to 111 state), such as traditional five-segment PWM; you can also use V 0 and V 7 in one PWM period at the same time, such as traditional seven Segment method PWM.

以五段法为例,它按照尽可能减少开关次数的原则来确定零矢量。在插入零矢量时,如果之前发的非零矢量对应的开关状态中有一个“1”,则插入000对应的零矢量V0;如之前发的非零矢量对应的开关状态中有两个“1”,则插入111对应的零矢量V7。仍以图3为例:Taking the five-segment method as an example, it determines the zero vector according to the principle of reducing the number of switches as much as possible. When inserting the zero vector, if there is a "1" in the switch state corresponding to the previously sent non-zero vector, then insert the zero vector V 0 corresponding to 000; if there are two "1" in the switch state corresponding to the previously sent non-zero vector 1", insert the zero vector V 7 corresponding to 111. Still taking Figure 3 as an example:

方式一:当使用V7时,各矢量发出的次序为Method 1: When V 7 is used, the order in which each vector is issued is

1、假设从V4出发:V4→V6→V71. Suppose starting from V 4 : V 4 →V 6 →V 7 ;

2、然后从V7出发:V7→V6→V4,又回到V42. Then start from V 7 : V 7 → V 6 → V 4 , and return to V 4 ;

3、回到1,重复该过程。3. Go back to 1 and repeat the process.

方式二:当使用V0时,各矢量发出的次序为Method 2: When V 0 is used, the order in which each vector is issued is

1、从V6出发:V6→V4→V01. Starting from V 6 : V 6 →V 4 →V 0 ;

2、然后从V0出发:V0→V4→V6,回到V62. Then start from V 0 : V 0 →V 4 →V 6 , return to V 6 ;

3、重复1、2步骤。3. Repeat steps 1 and 2.

为对称起见,传统五段法PWM技术中,这两种零矢量插入方式一般在各扇区间交替使用。For the sake of symmetry, in the traditional five-segment PWM technology, these two zero-vector insertion methods are generally used alternately between sectors.

但当采用三相电压型逆变器对电动机供电时,由于通常电机中性点悬空,故不同的PWM开关状态组合会在电机绕组中点与参考地之间产生高幅值(最大峰峰值可达直流母线电压)且高频交变的共模电压。研究表明,在各种杂散参数的作用下,该共模电压不仅会对周围环境产生电磁干扰,还是产生电机轴电压的重要根源,甚至可能击穿轴承油膜形成轴电流从而损坏电动机的轴承,缩短电动机使用寿命。However, when a three-phase voltage inverter is used to supply power to the motor, since the neutral point of the motor is usually suspended, different combinations of PWM switching states will generate high amplitudes between the midpoint of the motor winding and the reference ground (the maximum peak-to-peak value can be up to DC bus voltage) and high-frequency alternating common-mode voltage. Studies have shown that under the action of various stray parameters, the common-mode voltage will not only generate electromagnetic interference to the surrounding environment, but also an important source of motor shaft voltage, and may even break down the oil film of the bearing to form a shaft current and damage the motor bearing. Shortened motor life.

PWM调制过程中,产生高频高幅值共模电压的机理分析如下。During the PWM modulation process, the mechanism of generating high-frequency high-amplitude common-mode voltage is analyzed as follows.

参考图1,逆变器输出的共模电压ucom可表示为Referring to Figure 1, the common-mode voltage u com output by the inverter can be expressed as

uu comcom == 11 33 (( uu aa ++ uu bb ++ uu cc )) -- -- -- (( 33 ))

这里ua、ub、uc分别为三相定子绕组端点(图中a、b、c点)对地的电位。可见,共模电压的大小与逆变器开关状态有关,见表I。Here u a , u b , uc are the potentials of the three-phase stator winding terminals (points a, b, c in the figure) to ground respectively. It can be seen that the size of the common-mode voltage is related to the switching state of the inverter, see Table I.

表I逆变器开关状态与共模电压的关系Table I The relationship between inverter switch state and common mode voltage

Figure C20061016559100042
Figure C20061016559100042

其中,奇状态指有一相上桥臂导通、另外两相下桥臂导通,如100、001、010;偶状态与奇状态的情况正好相反,如110、011、101。Among them, the odd state refers to the conduction of the upper bridge arm of one phase and the conduction of the lower bridge arms of the other two phases, such as 100, 001, and 010;

由表I可知,当使用方式一时,共模电压波动范围从

Figure C20061016559100051
Figure C20061016559100052
即峰峰值为
Figure C20061016559100053
使用方式二时,共模电压波动范围为
Figure C20061016559100054
峰峰值也是但整体上,由于两种方式交替使用,其波动的峰峰值达Vdc,即与直流母线电压数值相等。如使用七段法SVPWM或者正弦PWM,由于在每个PWM周期内000和111开关状态均可出现,其共模电压在一个PWM周期内的波动峰峰值就可达到Vdc,因此情况更为严重。It can be seen from Table I that when using method 1, the common-mode voltage fluctuation range is from
Figure C20061016559100051
arrive
Figure C20061016559100052
That is, the peak-to-peak value is
Figure C20061016559100053
When using mode 2, the common mode voltage fluctuation range is
Figure C20061016559100054
Peak-to-peak is also But on the whole, since the two methods are used alternately, the peak-to-peak value of the fluctuation reaches V dc , which is equal to the value of the DC bus voltage. If the seven-segment method SVPWM or sinusoidal PWM is used, since 000 and 111 switching states can appear in each PWM cycle, the peak-to-peak fluctuation of the common-mode voltage in one PWM cycle can reach V dc , so the situation is more serious .

在PWM调制过程中,不同的开关状态交替出现,由此导致的共模电压的波动频率和PWM周期相对应,即与开关频率数量级相同。In the PWM modulation process, different switching states appear alternately, and the fluctuation frequency of the resulting common-mode voltage corresponds to the PWM cycle, that is, the order of magnitude is the same as the switching frequency.

鉴于高频(其频率和开关频率相同数量级)、大幅值的共模电压的危害,为了抑制共模电压以保护轴承、减小逆变器的负面效应,一般的做法是在系统中增加扼流装置或者滤波器,但这同时也使得成本、体积和系统复杂性大大增加。In view of the hazards of high frequency (its frequency is the same order of magnitude as the switching frequency) and large-scale common-mode voltage, in order to suppress the common-mode voltage to protect the bearing and reduce the negative effect of the inverter, the general practice is to add a choke to the system device or filter, but this also greatly increases the cost, size and system complexity.

其实,从表I中可以发现,非零状态产生的共模电压幅值仅为零状态(000、111)时的三分之一。由此可知,造成共模电压幅值过大的根本原因在于传统PWM方式中零矢量的大量使用。In fact, it can be found from Table I that the common-mode voltage amplitude generated by the non-zero state is only one-third of that of the zero state (000, 111). It can be seen that the root cause of the excessively large common-mode voltage amplitude lies in the extensive use of zero vectors in the traditional PWM method.

本发明基于如下思路:如果在PWM调制过程中尽量不使用零矢量,则其产生的共模电压就可以大大减小(减小为传统PWM技术的三分之一)。因此,本发明提出一种两相调制技术,采用三个相邻有效矢量来合成目标矢量,解决了使用零矢量导致共模电压幅值过高的问题。The present invention is based on the idea that if the zero vector is not used as much as possible in the PWM modulation process, the common-mode voltage generated by it can be greatly reduced (reduced to one-third of the traditional PWM technology). Therefore, the present invention proposes a two-phase modulation technique, which uses three adjacent effective vectors to synthesize the target vector, and solves the problem that the common-mode voltage amplitude is too high due to the use of zero vectors.

发明内容 Contents of the invention

根据上述问题,本发明的一个目的是提供一种PWM算法,使其产生尽量小的共模电压。本发明的另外一个目的是尽可能不增加或者减小开关器件动作次数,以减少由此引发的开关损耗和发热等其它问题。According to the above problems, an object of the present invention is to provide a PWM algorithm that generates a common-mode voltage as small as possible. Another object of the present invention is not to increase or reduce the number of switching device actions as much as possible, so as to reduce other problems such as switching loss and heat generated thereby.

本发明提出了一种新的PWM技术,即用三个相邻的有效矢量来合成目标电压矢量,从而避免使用零矢量,使得共模电压减小为普通PWM方法的三分之一,大大减小了共模电压。本发明的特征在于,该方法是在三相电压型逆变器-电动机系统中,在作为PWM信号发生单元的DSP中用对称的五段PWM法,以下述步骤依次实现的:The present invention proposes a new PWM technology, which uses three adjacent effective vectors to synthesize the target voltage vector, thereby avoiding the use of zero vectors and reducing the common-mode voltage to one-third of that of the common PWM method, greatly reducing the The common mode voltage is small. The present invention is characterized in that, the method is in the three-phase voltage type inverter-motor system, uses the symmetrical five-section PWM method in the DSP as PWM signal generation unit, realizes successively with following steps:

步骤一,在所述DSP中,设定当前时刻k,通过变压变频控制算法得到电压指令Vref kStep 1, in the DSP, set the current time k, and obtain the voltage command V ref k through the variable voltage variable frequency control algorithm,

步骤二,根据电压指令Vref k的相位角θ在空间的位置,确定其相邻的三个有效矢量,所述相邻是指从一个开关状态到另外一个开关状态只有一相开关动作的矢量,即:Vref k=klVl+kcVc+krVr Step 2, according to the position of the phase angle θ of the voltage command V ref k in space, determine its three adjacent effective vectors, the adjacent refers to a vector with only one phase switching action from one switching state to another switching state , that is: V ref k =k l V l +k c V c +k r V r

kl+kc+kr=1,k l +k c +k r =1,

其中,Vl、Vc、Vr是根据所述Vref k的相位角θ在空间的位置而确定的相邻的基本空间电压矢量,根据图2可以得到其对应的开关状态,表示为SI、Sc、Sr。Vr和Vc、Vc和Vl之间只有一相的开关动作,Among them, V l , V c , and V r are adjacent basic space voltage vectors determined according to the position of the phase angle θ of V ref k in space, and their corresponding switch states can be obtained according to Figure 2, denoted as S I , S c , S r . There is only one-phase switching action between V r and V c , V c and V l ,

kl、kc、kr分别是所述相邻矢量Vl、Vc、Vr的占空比,是设定值,k l , k c , k r are the duty ratios of the adjacent vectors V l , V c , V r respectively, and are set values,

步骤三,设定:PWM周期为TPWM,记:Tp=TPWM/2,DSP按下式计算Vl、Vr、Vc相应的作用时间Tl、Tr、和TcStep 3: Set: PWM period is T PWM , record: T p = T PWM /2, DSP calculates the action time T l , T r , and T c corresponding to V l , V r , V c according to the following formula:

TT ll == kk ll ** TT pp TT cc == kk cc ** TT pp TT rr == kk rr ** TT pp

Tl+Tc+Tr=TpT l +T c +T r =T p ,

步骤四,DSP按以下方式依次启动电压矢量:Step 4, the DSP starts the voltage vector sequentially in the following manner:

启动所述电压矢量Vr,发出Vr对应的逆变器开关状态Sr,保持时间为TrStart the voltage vector V r , send out the inverter switching state S r corresponding to V r , and keep it for T r ;

启动所述电压矢量Vc,发出Vc对应的逆变器开关状态Sc,保持时间为TcStart the voltage vector V c , send out the inverter switch state S c corresponding to V c , and keep it for T c ;

启动所述电压矢量Vl,发出Vl对应的逆变器开关状态SI,保持时间为2×TlStart the voltage vector V l , send out the inverter switching state S I corresponding to V l , and hold the time for 2×T l ;

再次启动所述电压矢量Vc,发出Vc对应的逆变器开关状态Sc,保持时间为TcStart the voltage vector V c again, send out the inverter switching state S c corresponding to V c , and hold the time for T c ;

再次启动所述电压矢量Vr,发出Vr对应的逆变器开关状态Sr,保持时间为TrStart the voltage vector V r again, send out the switching state S r of the inverter corresponding to V r , and hold the time for T r ;

步骤五,DSP使k→k+1,若Vref k+1=Vref k,则转步骤四;否则,转步骤二,进入下一个PWM周期。Step 5, DSP makes k→k+1, if V ref k+1 =V ref k , go to step 4; otherwise, go to step 2 to enter the next PWM cycle.

本发明具有如下特点:The present invention has following characteristics:

1.每个PWM周期内逆变器开关器件导通状态在不考虑死区的情况下含有三个相邻的开关状态组合,其中任何一种状态切换到另外一种状态只需一相开关器件动作;1. In each PWM cycle, the conduction state of the inverter switching device contains three adjacent switching state combinations without considering the dead zone, and any one state switches to another state only needs one phase switching device action;

2.每个PWM周期内始终有一相开关不动作,从而减少开关次数三分之一左右;2. In each PWM cycle, there is always a phase switch that does not act, thereby reducing the number of switches by about one-third;

3.共模抑制效果好,产生的共模电压其波动范围(峰峰值)仅为直流母线电压的三分之一;3. The common-mode suppression effect is good, and the fluctuation range (peak-to-peak value) of the common-mode voltage generated is only one-third of the DC bus voltage;

4.可以用软件实现,无需硬件成本。4. It can be realized by software without hardware cost.

附图说明 Description of drawings

图1.三相电压型逆变器-电动机系统示意图;Figure 1. Schematic diagram of a three-phase voltage inverter-motor system;

图2.基本空间电压矢量图;Figure 2. Basic space voltage vector diagram;

图3.传统矢量合成方式图;Figure 3. Traditional vector synthesis method diagram;

图4.本发明所应用的系统图;Fig. 4. the system diagram that the present invention is applied;

图5.采用三个相邻矢量合成参考电压矢量示意图;Figure 5. A schematic diagram of a reference voltage vector synthesized by three adjacent vectors;

图6.本发明的实验波形:Fig. 6. experimental waveform of the present invention:

6(a)传统七段法PWM共模电压波形,20V/格,1ms/格;6(a) Traditional seven-segment PWM common-mode voltage waveform, 20V/div, 1ms/div;

6(b)传统五段法PWM共模电压波形,20V/格,2ms/格;6(b) Traditional five-segment PWM common-mode voltage waveform, 20V/div, 2ms/div;

6(c)本发明PWM方法的共模电压波形,20V/格,2ms/格。6(c) Common-mode voltage waveform of the PWM method of the present invention, 20V/division, 2ms/division.

图7.DSP程序流程框图。Figure 7. DSP program flow diagram.

具体实施方式 Detailed ways

图4是本发明所应用的实际系统框图。一般地,该系统包括:直流电源1,提供系统运行所需能量;三相逆变器2,其输出连接到负载4(这里为电动机)上,响应PWM指令来将直流电变换成交流电来驱动电动机工作;以及控制系统,包括电压、电流等物理量的检测环节(5、7、9)和控制指令输入部分和算法部分8。控制算法利用各种输入量,通过一定控制策略,计算得到所需电压的指令信号Vref,PWM发生单元6(矩形虚线框所示)将该信号变换成PWM信号送到逆变器以驱动各开关器件的开通与关断。其中8和6可在CPU中由软件实现。本发明即在PWM发生单元中,用以提供一种新的PWM产生方式。Fig. 4 is a block diagram of an actual system to which the present invention is applied. Generally, the system includes: a DC power supply 1, which provides the energy required for system operation; a three-phase inverter 2, whose output is connected to a load 4 (here, a motor), and responds to PWM commands to convert DC power into AC power to drive the motor work; and a control system, including detection links (5, 7, 9) of physical quantities such as voltage and current, and a control instruction input part and an algorithm part 8. The control algorithm uses various input quantities and through a certain control strategy to calculate the command signal V ref of the required voltage. The PWM generating unit 6 (shown by the rectangular dotted line) converts the signal into a PWM signal and sends it to the inverter to drive each Turning on and off of switching devices. Among them, 8 and 6 can be implemented by software in the CPU. The present invention is used in the PWM generation unit to provide a new PWM generation method.

本发明提出的矢量合成方法如图5所示。当参考电压矢量Vref位于图中所示位置时,不使用零矢量,而是使用三个相邻的有效矢量V4、V6、V2来合成参考电压矢量。这里“相邻”的意义为从一个开关状态到另外一个开关状态只有一相开关动作。即The vector synthesis method proposed by the present invention is shown in FIG. 5 . When the reference voltage vector V ref is at the position shown in the figure, instead of using the zero vector, three adjacent active vectors V 4 , V 6 , V 2 are used to synthesize the reference voltage vector. The meaning of "adjacent" here is that there is only one phase switching action from one switching state to another switching state. Right now

Vref=klV2+kcV6+krV4           (4)V ref =k l V 2 +k c V 6 +k r V 4 (4)

这里here

kl+kc+kr=1                   (5)k l +k c +k r =1 (5)

从这三个有效矢量对应的开关状态010、110和100可以看出,c相开关状态始终为0,因此在整个PWM周期内,c相开关不动作,从而将开关次数减小了三分之一左右。From the switching states 010, 110, and 100 corresponding to these three effective vectors, it can be seen that the c-phase switch state is always 0, so the c-phase switch does not act during the entire PWM cycle, thereby reducing the switching times by one-third one or so.

以图5中Vref的所示位置为例,本发明的第一种可行的实施方案为(步骤1之前的数据采集、计算等通用步骤略去):Taking the shown position of V ref among Fig. 5 as an example, the first feasible implementation scheme of the present invention is (general steps such as data collection, calculation before step 1 are omitted):

1、设当前时刻为k,通过控制算法(如变压变频控制、矢量控制等,可参考陈伯时等专家的相关论著[1-3]),得到电压指令Vref k1. Set the current moment as k, and obtain the voltage command V ref k through the control algorithm (such as variable voltage variable frequency control, vector control, etc., refer to the relevant works of experts such as Chen Boshi [1-3] );

2、根据电压指令Vref k在空间的位置,确定其最接近的三个有效矢量。记Vref k的相角为θ,则有效矢量可根据θ角的范围来确定,如下表所示。(例:图5中目标向量相角在45度左右,故有效矢量为V2、V6和V4)2. According to the position of the voltage command V ref k in space, three effective vectors closest to it are determined. Record the phase angle of V ref k as θ, then the effective vector can be determined according to the range of θ angle, as shown in the table below. (Example: in Figure 5, the phase angle of the target vector is about 45 degrees, so the effective vectors are V 2 , V 6 and V 4 )

表II扇区划分与矢量选择Table II sector division and vector selection

Figure C20061016559100081
Figure C20061016559100081

3、根据式(4)和(5)计算得到各个有效矢量的占空比kl、kr、kc3. Calculate the duty cycle k l , k r , k c of each effective vector according to formulas (4) and (5);

4、记PWM周期为Tpwm,记Tp=Tpwm/2。计算4. Record the PWM period as T pwm , and record T p =T pwm /2. calculate

TT ll == kk ll ** TT pp TT cc == kk cc ** TT pp TT rr == kk rr ** TT pp -- -- -- (( 66 ))

5、出开关状态100(即A相上桥臂导通,下桥臂关断;B相下桥臂导通,上桥臂关断;C相下桥臂导通,上桥臂关断),保持时间为Tr5. Output switching state 100 (that is, the upper bridge arm of phase A is turned on and the lower bridge arm is turned off; the lower bridge arm of phase B is turned on and the upper bridge arm is turned off; the lower bridge arm of phase C is turned on and the upper bridge arm is turned off) , the holding time is T r ;

6、发出开关状态110,保持时间为Tc6. Send the switching state 110, and the holding time is T c ;

7、发出开关状态010,保持时间为2×Tl7. Send the switching state 010, and the holding time is 2×T l ;

8、发出开关状态110,保持时间为Tc8. Send the switching state 110, and the holding time is T c ;

9、发出开关状态100,保持时间为Tr9. Send the switching state 100, and the holding time is T r ;

10、步骤1方法计算新的k+1时刻的电压指令值Vref k+110. The method of step 1 calculates the voltage command value V ref k+1 at the new time k+ 1 ;

11、Vref k+1=Vref k,转步骤5;否则令 k < = k + 1 , 转步骤2。进入下一PWM周期,循环执行。11. V ref k+1 = V ref k , go to step 5; otherwise set k < = k + 1 , Go to step 2. Enter the next PWM cycle and execute cyclically.

第二种实施方案:Second implementation:

1~4步骤同第一方案;Steps 1 to 4 are the same as the first plan;

5、发出开关状态010,保持时间为Tl5. Send switch status 010, hold time T l ;

6、发出开关状态110,保持时间为Tc6. Send the switching state 110, and the holding time is T c ;

7、发出开关状态100,保持时间为2×Tr7. Send the switching state 100, and the holding time is 2×T r ;

8、发出开关状态110,保持时间为Tc8. Send the switching state 110, and the holding time is T c ;

9、发出开关状态010,保持时间为Tl9. Send the switching state 010, and the holding time is T l ;

后面步骤同第一方案。The following steps are the same as the first scheme.

第三种方案:The third option:

1~3步骤同第一方案;Steps 1 to 3 are the same as the first plan;

4、记PWM周期为Tpwm。计算4. Record the PWM period as T pwm . calculate

TT ll == kk ll ** TT pwmpwm TT cc == kk cc ** TT pwmpwm TT rr == kk rr ** TT pwmpwm -- -- -- (( 77 ))

5、发出开关状态100,保持时间为Tr5. Send the switching state 100, and the holding time is T r ;

6、发出开关状态110,保持时间为Tc6. Send the switching state 110, and the holding time is T c ;

7、发出开关状态010,保持时间为Tl7. Send the switching state 010, and the holding time is T l ;

8、按步骤1方法计算新的k+1时刻的电压指令值Vref k+18. Calculate the new voltage command value V ref k+1 at time k+1 according to step 1;

9、若Vref k+1=Vref k,转步骤5;否则令 k < = k + 1 , 转步骤2。进入下一PWM周期,循环执行。9. If V ref k+1 = V ref k , go to step 5; otherwise set k < = k + 1 , Go to step 2. Enter the next PWM cycle and execute cyclically.

第四种方案:The fourth option:

步骤1~4同第三方案;Steps 1-4 are the same as the third scheme;

5、发出开关状态010,保持时间为Tl5. Send switch status 010, hold time T l ;

6、发出开关状态110,保持时间为Tc6. Send the switching state 110, and the holding time is T c ;

7、发出开关状态100,保持时间为Tr7. Send the switching state 100, and the holding time is T r ;

此后步骤同第三方案。The steps thereafter are the same as the third scheme.

还可以以更多不同的实现方式实现本发明,而没有背离本发明的精神,即在一个PWM周期内出现的逆变器开关器件状态在不考虑死区效应的情况下有三种组合,从一种组合到另一种组合只需一相开关器件动作。所述的实施方案是说明性的而不是限制性的。因此,落入权利要求书的界限和范围或者这种界限和范围的等价之内的所有改变包含在权利要求书中。例如,可以不计算各有效矢量的占空比,而是直接计算得到或者通过调制波与载波比较的方式得到三相开关动作的时刻以获得类似的PWM波形。The present invention can also be implemented in more different ways without departing from the spirit of the present invention, that is, there are three combinations of inverter switching device states occurring within one PWM cycle without considering the dead zone effect, from one From one combination to another, only one phase switching device is required to act. The described embodiments are illustrative rather than restrictive. All changes that come within the metes and bounds of the claims, or equivalents of such metes and bounds, are therefore embraced in the claims. For example, instead of calculating the duty cycle of each effective vector, it can be directly calculated or obtained by comparing the modulation wave with the carrier to obtain the moment of the three-phase switching action to obtain a similar PWM waveform.

为验证本发明的实际效果,在一套样机系统中采用不同PWM技术做了对比实验。In order to verify the actual effect of the present invention, a comparative experiment was done using different PWM techniques in a prototype system.

实验系统如图1、4所示,其中:直流母线电压120V;逆变器负载为4kW三相异步电动机;控制算法为变压变频(VVVF)控制。The experimental system is shown in Figures 1 and 4, where: the DC bus voltage is 120V; the inverter load is a 4kW three-phase asynchronous motor; the control algorithm is VVVF control.

实验中具体实施步骤为:The specific implementation steps in the experiment are:

1.设当前时刻为k。利用VVVF控制算法,计算电压指令Vref k,这一步骤又可分以下几个小步骤:1. Let the current moment be k. Using the VVVF control algorithm to calculate the voltage command V ref k , this step can be divided into the following sub-steps:

1.1从控制给定信号中得到给定的频率指令f;1.1 Obtain the given frequency command f from the control given signal;

1.2根据VVVF原理,按下式计算电压指令Vref k的幅值1.2 According to the principle of VVVF, calculate the amplitude of the voltage command V ref k according to the following formula

Vref k=Cf                     (8)V ref k =Cf (8)

其中,C为压频比常数。Among them, C is the voltage-frequency ratio constant.

1.3计算相角增量1.3 Calculate the phase angle increment

Δθk=2π*f*Tpwm             (9)Δθ k = 2π * f * T pwm (9)

设上一时刻相角为θk-1,则当前时刻的相角θkAssuming that the phase angle at the previous moment is θ k-1 , then the phase angle θ k at the current moment is

θk=θk-1+Δθk              (10)θ k =θ k-1 +Δθ k (10)

1.4则当前时刻的电压指令Vref k的幅值为Vref,相角为θk,即1.4 Then the amplitude of the voltage command V ref k at the current moment is V ref and the phase angle is θ k , namely

VV refref kk == VV refref &angle;&angle; &theta;&theta; kk -- -- -- (( 1111 ))

2.据电压指令Vref k在空间的位置,确定其最接近的三个有效矢量。由Vref k的相角θk,可根据其范围来确定有效矢量组合,如下表所示。(例:图4中目标向量相角在45度左右,故有效矢量为V2、V6和V4)2. According to the position of the voltage command V ref k in space, determine its three closest effective vectors. From the phase angle θ k of V ref k , the effective vector combination can be determined according to its range, as shown in the table below. (Example: in Figure 4, the phase angle of the target vector is about 45 degrees, so the effective vectors are V 2 , V 6 and V 4 )

3.根据(4)和(5)计算得到各个有效矢量的占空比kl、kr、kc3. According to (4) and (5), the duty cycle k l , k r , k c of each effective vector are obtained;

4.记PWM周期为Tpwm,记Tp=Tpwm/2。计算4. Record the PWM period as T pwm , and record T p =T pwm /2. calculate

TT ll == kk ll ** TT pp TT cc == kk cc ** TT pp TT rr == kk rr ** TT pp -- -- -- (( 1212 ))

5.发出开关状态100(即A相上桥臂导通,下桥臂关断;B相下桥臂导通,上桥臂关断;C相下桥臂导通,上桥臂关断),保持时间为Tr5. Send the switch status 100 (that is, the upper bridge arm of phase A is turned on and the lower bridge arm is turned off; the lower bridge arm of phase B is turned on and the upper bridge arm is turned off; the lower bridge arm of phase C is turned on and the upper bridge arm is turned off) , the holding time is T r ;

6.发出开关状态110,保持时间为Tc6. Send the switching state 110, and the holding time is T c ;

7.发出开关状态010,保持时间为2×Tl7. Send switch state 010, hold time is 2×T l ;

8.发出开关状态110,保持时间为Tc8. Send the switching state 110, and the holding time is T c ;

9.发出开关状态100,保持时间为Tr9. Send the switching state 100, and the holding time is T r ;

10.由步骤1方法计算新的k+1时刻的电压指令值Vref k+110. Calculate the new voltage command value V ref k+1 at time k+1 by the method in step 1;

11.若Vref k+1=Vref k,转步骤5;否则令 k < = k + 1 , 转步骤2。进入下一PWM周期,循环执行。11. If V ref k+1 = V ref k , go to step 5; otherwise set k < = k + 1 , Go to step 2. Enter the next PWM cycle and execute cyclically.

采用本发明中PWM技术所得共模电压实验波形如图6(c)所示。可见,共模电压变化的波动范围在40V左右,即为直流电压的三分之一。The experimental waveform of the common-mode voltage obtained by using the PWM technique in the present invention is shown in FIG. 6(c). It can be seen that the fluctuation range of the common mode voltage is about 40V, which is one-third of the DC voltage.

为了便于对比,图6(a)给出了普通七段法空间电压矢量PWM的实验波形,图6(b)则为普通五段法空间电压矢量PWM的实验波形。从实验波形中可以看出,传统七段法共模电压峰峰值等于直流母线电压;传统五段法共模电压波动峰峰值在小区间内(一个扇区)为80V左右,但全局峰峰值仍为直流母线电压120V。For the sake of comparison, Figure 6(a) shows the experimental waveform of the common seven-segment space voltage vector PWM, and Figure 6(b) shows the experimental waveform of the common five-segment space voltage vector PWM. It can be seen from the experimental waveforms that the peak-to-peak value of the common-mode voltage of the traditional seven-segment method is equal to the DC bus voltage; the peak-to-peak value of the common-mode voltage fluctuation of the traditional five-segment method is about 80V within a small area (one sector), but the global peak-to-peak value is still The DC bus voltage is 120V.

从图6中的实验波形对比中可知,使用本发明的PWM技术,其共模电压幅值可降低为传统方法的三分之一,从而大大降低了共模电压的危害。因此,本发明相对传统PWM技术,在抑制共模电压、减小共模干扰和轴电压危害等方面,优势十分明显。From the comparison of the experimental waveforms in Fig. 6, it can be known that using the PWM technology of the present invention, the amplitude of the common-mode voltage can be reduced to one-third of that of the traditional method, thereby greatly reducing the harm of the common-mode voltage. Therefore, compared with the traditional PWM technology, the present invention has obvious advantages in suppressing common-mode voltage, reducing common-mode interference and shaft voltage hazards, and the like.

应当指出,上述的实施例亦是说明而不是限制本发明,并且本领域技术人员能够在不背离所附权利要求的范围条件下设计许多实施例。It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many embodiments without departing from the scope of the appended claims.

Claims (3)

1. two phase PWM modulation method that reduces common-mode voltage,
It is characterized in that this method is to realize with following steps in sequence with five sections symmetrical PWM methods in as the DSP of pwm signal generating unit in three-phase voltage-type inverter-electric motor system:
Step 1 in described DSP, is set current time k, obtains voltage instruction V by the variable voltage variable frequency control algolithm Ref k,
Step 2 is according to voltage instruction V Ref kPhase angle θ in the position in space, determine three effective vectors that it is adjacent, the described adjacent vector that has only a phase switch motion from an on off state to the another one on off state, that is: the V of being meant Ref k=k lV l+ k cV c+ k rV r
k l+k c+k r=1,
Wherein, V l, V r, V cBe according to described V Ref kPhase angle θ in the position in space and definite adjacent fundamental space voltage vector, V rAnd V c, V cAnd V lBetween have only the switch motion of a phase,
k l, k c, k rIt is respectively described adjacent vector V l, V c, V rDuty ratio, be set point,
Step 3, set: the PWM cycle is T PWM, note: T p=T PWM/ 2, DSP is calculated as follows V l, V r, V cCorresponding action time T l, T r, and T c:
T l = k l * T p T c = k c * T p T r = k r * T p
T l+T c+T r=T p
Step 4, DSP is starting resistor vector successively in the following manner:
Start described voltage vector V r, send V rCorresponding inverter switching states S r, the retention time is T r
Start described voltage vector V c, send V cCorresponding inverter switching states S c, the retention time is T c
Start described voltage vector V l, send V lCorresponding inverter switching states S l, the retention time is 2 * T l
Start described voltage vector V once more c, send V cCorresponding inverter switching states S c, the retention time is T c
Start described voltage vector V once more r, send V rCorresponding inverter switching states S r, the retention time is T rStep 5, DSP makes k → k+1, if V Ref K+1=V Ref k, then change step 4; Otherwise, change step 2, enter the next PWM cycle.
2. a kind of two phase PWM modulation method that reduces common-mode voltage according to claim 1 is characterized in that, in described step 4, the mode of DSP starting resistor vector is undertaken by following order successively: V l→ V c→ V r→ V c→ V l
3. a kind of two phase PWM modulation method that reduces common-mode voltage according to claim 1 and 2 is characterized in that described T p=T PWM
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Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8115430B2 (en) * 2009-05-28 2012-02-14 GM Global Technology Operations LLC Methods, systems and apparatus for controlling operation of two alternating current (AC) machines
JP5530905B2 (en) * 2010-11-19 2014-06-25 日立アプライアンス株式会社 Motor controller, air conditioner
CN102355153A (en) * 2011-09-07 2012-02-15 南昌航空大学 Three-level space vector pulse width modulation method capable of balancing midpoint potential of bus and reducing loss of inverter
EP2605399A4 (en) 2011-10-17 2014-02-26 Panasonic Corp MOTOR DRIVE SYSTEM AND METHOD OF CONTROLLING THE SAME
CN102843096B (en) * 2012-06-13 2014-12-24 上海晟矽微电子股份有限公司 Method of controlling N electrical level inverters
CN102882399B (en) * 2012-06-13 2015-08-05 上海晟矽微电子股份有限公司 For the control algolithm of variable-frequency motor at the circuit implementing method of inverter
CN103580465B (en) * 2013-11-21 2015-11-18 中国矿业大学 A Simplified Modulation Algorithm for Restraining the Common Mode Voltage of Three-phase PWM Converter
JP5900470B2 (en) * 2013-11-28 2016-04-06 株式会社安川電機 Current source power converter
CN104038094B (en) * 2014-04-01 2017-01-18 燕山大学 Control method of non-isolated three-phase photovoltaic grid-connected inverter
CN106655868A (en) * 2015-10-29 2017-05-10 中车大连电力牵引研发中心有限公司 Zero vector optimization SVPWM modulation method and device
CN106787985A (en) * 2017-01-23 2017-05-31 长安大学 A kind of switch list optimization method based on permagnetic synchronous motor Direct Torque Control
CN107070361B (en) * 2017-03-30 2019-02-12 沈阳工业大学 A SVPWM control method for reducing common mode voltage of six-phase motor
CN106992734A (en) * 2017-04-26 2017-07-28 长安大学 An optimization method for direct torque control of permanent magnet synchronous motor with variable voltage vector
CN110768553B (en) * 2019-10-28 2021-10-01 上海大郡动力控制技术有限公司 Combined zero-vector-free overmodulation method for electric vehicle inverter
CN110932589B (en) * 2019-12-18 2021-01-19 华中科技大学 A SVPWM modulation method for reducing the common-mode voltage on the AC side of the inverter
CN111600522B (en) * 2020-05-08 2021-09-28 北方工业大学 Motor model prediction current control method and device, electronic equipment and medium
CN113783501B (en) * 2020-06-09 2024-01-26 美的威灵电机技术(上海)有限公司 Motor driver, driving control method and device thereof and electronic equipment
CN113271027B (en) * 2021-07-12 2021-09-17 希望森兰科技股份有限公司 Diode-clamped high-performance synchronous overmodulation algorithm for three-level inverter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003018853A (en) * 2001-06-28 2003-01-17 Fuji Electric Co Ltd Common mode current reduction method
US20030128146A1 (en) * 2002-01-10 2003-07-10 Matsushita Electric Industrial Co., Ltd. Semiconductor device for inverter controlling
JP2004274806A (en) * 2003-03-05 2004-09-30 Nissan Motor Co Ltd Motor controller
US20060034364A1 (en) * 2004-08-13 2006-02-16 Breitzmann Robert J Carrier synchronization to reduce common mode voltage in an AC drive
CN2794029Y (en) * 2005-04-29 2006-07-05 哈尔滨理工大学 Frequency transformer of active low-throughout filter with common-mode voltage elimination

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003018853A (en) * 2001-06-28 2003-01-17 Fuji Electric Co Ltd Common mode current reduction method
US20030128146A1 (en) * 2002-01-10 2003-07-10 Matsushita Electric Industrial Co., Ltd. Semiconductor device for inverter controlling
JP2004274806A (en) * 2003-03-05 2004-09-30 Nissan Motor Co Ltd Motor controller
US20060034364A1 (en) * 2004-08-13 2006-02-16 Breitzmann Robert J Carrier synchronization to reduce common mode voltage in an AC drive
CN2794029Y (en) * 2005-04-29 2006-07-05 哈尔滨理工大学 Frequency transformer of active low-throughout filter with common-mode voltage elimination

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