外文翻译---关于交流伺服驱动器的死区效应的分析与补偿.docx

外文资料原文Analysis And Compensation Of Dead TimeEffectsFor The AC Servo DriverHaitao Qin1, Anwen Shen2, Qiao Zhang3,Wenyu Wang4Department of Control Science and Engineering, HuaZhong University of Science and Technology, ChinaAbstractA on-line dead time compensation method for the alternating current (AC) servo is proposed. By apply the Fast Fourier Transform (FFT) to the compensating voltage in one period of three phase output current, without any additional hardware, the dead time effects is eliminated by compensate the 1th, 5th, 7th harmonic components only. The results of simulations and experiments well demonstrate the effectiveness of the proposed method.Index Terms-AC-Servo, Dead-Time Compensation,Permanent magnet synchronous motor (PMSM).I. INTRODUCTIONFor the storage effect of power device, its very necessary to set a dead-time on both switches in an inverter leg to avoid the shoot-through in the dc-link. According to the Insulated Gate Bipolar Transistors (IGBT) performance, we usually set the dead time as 25us, this distorts the voltage source inverters (VSI) output voltage, resulting in phase current distortions, torque ripples and degradations of control performance. To overcome the dead-time effect, various approaches have been studied and applied. Conventionally, error voltage due to the dead-time effect can be pre-calculated and compensated by adding them to the 3-phase reference voltage according to the phase current polarity1-2. A on-line compensation method is presented in 3, compute the error voltage by compare the reference voltage with the real voltage, and then add this to next reference voltage as the new reference. In this approach, the error voltage which caused by many reasons such as dead-time, dc-link voltage drops, etc can be eliminated. However, estimation of the real voltage should use the parameter of motor which are not fixed value but varying while at working. In 4, dead-time effect is compensated by modified PWM gate signals with hardware circuits. In 6, a method which change the PWM gate signal on-line based on the polarity of phase current is presented. All the approaches mentioned above can eliminate the deadtime effect greatly and have a good performance, however, with the increase of complexity of the software and hardware, which restrict the practicability.Thus, In the paper, a method based on the 2-phase stationary frame is proposed. The proposed method produces the compensating signal by use the phase of the current only, does not need any additional hardware circuits.II. ANALYSIS OF DEAD-TIME EFFECTIts convenient to analyze the dead-time effects from one phase leg of the inverter and extend the result to other phase legs. Figure.1 shows the basic configuration of onephase leg of the inverter. Define the direction of phase current flow to load is positive.Figure.1. one phase leg of the inverterA. when phase current ia is positive:When upper switch A+ turn on, lower switch A- turn off: During the dead-time and before the A+ turn on completely, the voltage of point a is clamped to Udc/2 for the D- turned on, the phase current flows through A+until A+ turned on, thus, the error time caused by deadtime effect is Td+ton, where ton is the IGBTs turn on delay time.When upper switch A+ turn off, lower switch A- turn on: phase current flows through A+ before A+ turned off, and flows through D- when turned off. Thus, the error time caused by dead-time effect is toff, where toff is the IGBTs turn off delay time.B. when phase current ia is negtive:When upper switch(A+)-turn on, lower switch (A-) turn off: phase current flows through A- before A- turned off, and flows through D+ when turned off. Thus, the error time caused by dead-time effect is toff. When upper switch (A+) turn off, lower switch (A-) turn on: During the dead-time and before A- turn on completely, the voltage of point a is clamped to +Udc/2 for D+ turned on. Thus, the error time caused by deadtime effect is Td+ton.Figure.2(a) shows the ideal gate signal patterns, Figure.2(b) shows the practical signal patterns considering the dead-time, Figure.2(c) shows the actual output voltage considering the dead-time and switching time for ia0 and ia0和0的转换时间的实际输出电压。图2、考虑死区时间和打开/关闭的开关设备的时间的实际切换模式。（a）理想门极信号模式（b）考虑死去时间的是极信号模式 (c)考虑死去时间和转换时间的实际输出电压平均误差电压可以从图2中计算出如下（1）： （1）其中 ，。根据（1），死去时间效应最明显的影响是降低输出电压，导致相电流谐波，转矩脉动和速度波动，特别是在低转速。三、死区时间效应的补偿补偿的主要原理是产生一个同样的幅度和符号相反的电压以降低误差电压或消除死区时间的影响。从（1）中可知，依赖于死区时间、开关时间，切换时间和直流链接电压误差电压的振幅是固定的离线补偿。补偿的关键是要判断相电流的极性。在实时控制系统准确的判断相电流极性是很难的，然而，相电流零点的含糊不清会恶化补偿的效果。因此，在本文提出了一种仅在两相静止坐标系（/）中依靠电流的相数的补偿方法。误差电压取决于相电流的极性所以三相电流将有6个不同组合的误差电压矢量。 表I显示误差电压和三相电流不同极性的矢量，。 表 I 基于三相电流极性的误差电压矢量图3显示了补偿电压矢量。该补偿电压矢量间断的移动，并且它的轨迹是六边形。图3.补偿电压矢量在两相旋转坐标中的电流矢量如图4所显示。相电流矢量可由图4获得：。图4.相电流矢量 转子磁场定向控制技术在伺服控制系统中可以用来控制永磁同步电动机，实现通过控制以达到去耦合，因此，。关于误差电压矢量的电流矢量如表II所显示:表II关于误差电压矢量的电流矢量通过考虑周期性和补偿电压矢量在/坐标中的奇偶性，傅立叶变换可概括为（2）： （2）其中可以计算如（3） （3）以类似的方法，表示如（4） （4）把（3）和（4）代入（2）中，可得在坐标系中的补偿电压如下： （5）从（5）中知，并没有如3次、9次谐波那样的零相电压，高次的奇次谐波对输出电压失真只有很小的影响。因此，其足以弥补由基波，5次和7次谐波补偿所引起的死去时间的影响。包含了死区时间补偿的矢量控制的框图如图5所示。 图5. 包含死区时间补偿的磁场定向控制框图四、死区效应的仿真初步的模拟分析已经完成用以测试验证的补偿。符合图5的伺服系统的仿真模块已经建立。电机的测试参数已经在表III中列出。由于操作条件，一个参考速度为60r/min和负载转矩为2Nm实行了。该控制调制频率10 kHz的采样已经实施，而4.8us延迟时间已作为系统的死区时间考虑。表III. 测试电机的参数额定功率1.3kw额定速度2500r/min额定扭矩5Nm额定电流5A转动惯量1.94*10-3kgm2定子相电阻0.86ohm定子相电感3.03mH机械时间常数1.78ms反电动势常数39.36V/KRPM 图6显示了在使用死去时间补偿之前和之后电流和电压的仿真结果。我们可以看到由于死区效应的影响相电流产生严重的失真，这种失真在建议的计划中被显著的降低。(a)死区时间的影响（b）存在死区时间的影响图6.电压和电流的仿真结果五、实验结果建议的补偿方法是使用一个基于DSP的永磁同步电动机控制系统来实现。该处理器是定点DSP（TMS320LF2407A）有一个40MHz的时钟。该HCPL-7840隔离放大器是用来测量相电流和直流电压，测量信号转换成数字值是通过使用一个10位分辨率的模拟数字转换器（ADC）来实现的。一个有2500-pulse/rev分辨率和位置处理器增量编码器是用来获取的转子磁链的位置和测量转子的速度。该方案的速度测量是考虑编码器分辨率和系统的采样周期的2r/min。三相逆变器是通过使用智能功率模块包括六个IGBT，门驱动器和保护电路而构造成的。与有补偿方案的控制系统的表现相比较的是无补偿方案的控制系统。 图7（a）显示了没有死区时间补偿的相电流的实验结果。没有补偿方案，死区时间在相电流中引起了我们不需要的电流。然而，在提出的补偿方案中，这些失真被完全清除如图7（b）所示。 （a）无补偿（b）有补偿图7.一相电流实验结果图8描述了在60r/min的稳态速度。考虑到测量误差的为2r/min时，无死区时间补偿的速度误差是2r/min，当补偿方法被应用时此值降低至0。（a）无补偿 （b）有补偿图8.相速度的实验结果六、结 论 在没有任何外加硬件的情况下， 对三相电流的一个阶段内的补偿电压应用快速傅里叶变换（FFT），通过补偿第1，第5，第7次谐波成分排除了死区时间的影响。这种补偿方法是基于二相静止坐标系的。仿真和实验结果充分验证了补偿算法的有效性七、参考文献1 Seung-Gi Jeong, Min-Ho Park. The analysis andcompensation of dead-time effects in PWMinvertersJ.Industrial Applications, IEEE Transactions,1991, 38(2):108-114.2 Sukegawa. T, Kamiyama. K, Mizuno. K, Matsui. T,Okuyama. T, Fully digital, vector-controlled PWM VSIfed AC drives with an inverter dead-time compensation strategyJ. Industry Applications, IEEE Transactions, 1991, 27(3):552-5593 Hyun-Soo Kim, Hyung-Tae Moon, Myung-Joong Youn. On-line dead-time compensation method using disturbance observerJ. Power Electronics , IEEE Transactions, 2003, 18(6): 1336-1345.4 Y. Murai, T. Watanabe, H. Iwasaki. Waveform distortion and correction circuit for PWM inverters with swtiching lag-timeJ. Industrial Applications, IEEE Transactions, 1987, 23(5):881-886.5 Urasaki N, Senjyu T. A dead-time compensation strategy for permanent magnet synchronous motor driv suppressing current distortionC/ The 29th Annual Conference of the IEEE on Industrial Electronics Society, Virginia, USA: IEEE, 2003,2:1255-1260.6 D. Leggate, R. J. Kerkman. Pulse-Based Dead-Time Compensator for PWM Voltage InvertersJ. Industrial Applications, IEEE Transactions, 1997, 44(2):191-197.The general staff (1 employees in addition to v