ThreePhase ThreeLevel PWM Converter三相三电平PWM转换器.docx

ThreePhase ThreeLevel PWM Converter三相三电平PWM转换器Three-Phase Three-Level PWM Converte 三相三电平PWM变换器 This example shows the harmonic analysis of PWM waveforms using the Powergui/FFT tool. P. Giroux and G. Sybille (Hydro-Quebec) 这个例子显示了使用Powergui / FFT工具PWM波形的谐波分析。 P. Giroux和G. Sybille） Description The system consists of two three-phase three-level PWM voltage source converters connected in twin configuration The inverter feeds an AC load (1kW, 500 var 60Hz 208 Vrms) through a three-phase transformer. Harmonic filtering is performed by the transformer leakage inductance (8%) and load capacitance (500 var). 该系统由两个三相三电平PWM电压源转换器连接的双配置逆变器交流负载通过一个三相变换变压器。谐波滤波进行变压器漏感和负载电容。 Each of the two inverters uses the Three-Level Bridge block where the specified power electronic devices are IGBT/Diode pairs. Each arm consists of 4 IGBTs, 4 antiparallel diodes, and 2 neutral clamping diodes. 每两个逆变器采用三电平桥块指定的电力电子器件，IGBT /二极管对。每个臂由4个IGBT反并联二极管，4，和2的中性ClampiNG二极管。 The inverter is controlled in open loop. PWM Generator blocks generates sets of 12 pulses. They can operate either in synchronized or un-synchronized mode. When operating in synchronized mode, the carrier triangular signal is synchronized on a PLL reference angle connected to input 'wt'. In synchronized mode, the carrier chopping frequency is specified by the switching ratio as a multiple of the output frequency. 逆变器控制在开环。脉宽调制发生器块产生12个脉冲组。他们可以操作无论是在同步或不同步模式。当在同步模式下运行时，汽车河流三角信号同步锁相环的参考角度连接到输入“重量”。在同步模式下，载波斩波频率被指定的开关比作为一个多个O输出频率。 Three sinusoidal 0.85 pu modulating signals are used to obtain a modulation index of 0.85. The carrier signals are synchronized on the modulating signals. in thePWM Generator block, you can instead select 'Unsynchronized' and 'Internal generation of modulating signals'. In such a case the magnitude (modulation index), frequency and phase angle of the output signals are specified directly inside the PWM Generator block menu. 三正弦0.85浦调制信号被用来获得0.85的调制指数。载波信号在调制信号上是同步的。在PWM发生器模块，你可以代替硒调制信号的选择'同步'和'内在生成。在这种情况下，指定的输出信号的幅度，频率和相位角的直接内E型脉宽调制发生器块菜单。 For this example the DC bus voltage is 400V (+/- 200 V), chopping frequency is 1080 Hz (18*60 Hz), magnitude of the three modulating signals is 0.85 (corresponding to a modulation index m = 0.85) and the frequency of the three generated signals is 60 Hz. 本例中的直流母线电压为400V，斩波频率为1080 Hz，这三个调制信号的幅度是0.85和产生的三个信号的频率为60赫兹。 In order to allow further signal processing, signals displayed on the Scope block (sampled at simulation sampling rate of 3240 samples/ cycle) are stored in a variable named 'psb3phPWM3level_str' (structures with time) . 为了让进一步的信号处理，在范围块显示信号都存储在一个变量名为“psb3phpwm3level_str” Simulation Run the simulation and observe the following three waveforms on the Scope block: Phase-neutral voltage Van_inv1 generated by inverter 1 (trace 1), phase A voltage Vaa_inverter generated by the twin inverter (trace 2) and phase-phase load voltage Vab_load (trace 3). The Van_inv1 waveform cleary shows the three levels: +200 V, 0 V, and -200 V. 运行仿真并观察以下三个波形的范围块：相中性点电压由逆变器产生的van_inv1 1，相电压vaa_inverter由双的情况和相位相负载电压vab_load。的van_inv1波形Cleary表示的三个层次：+ 200 V、0 V和200 V， Once the simulation is completed, open the Powergui and select 'FFT Analysis' to display the 0 - 5000 Hz frequency spectrum of signals saved in the 'psb3phPWM3level_str' structure. The FFT will be performed on a 2-cycle window starting at t = 0.1 - 2/60 (last 2 cycles of recording). Select the input labeled 'Vaa _inverter'. Click on Display and observe the frequency spectrum of last 2 cycles. The fundamental component of Vaa_inverter and THD for the 0 - 5000 Hz frequency range are displayed above the spectrum window. Because of the forward voltage drops in the IGBTs (Vf=1 V) and diodes (Vfd=1V), the magnitude of the fundamental voltage of the inverter (335 V) is slightly lower than the theoretical value (340 V for m=0.85). As expected for a twin inverter, first harmonics occur around multiples of double of carrier frequency (n*2*1080 Hz +- k*60Hz). 一旦仿真完成后，打开Powergui选择FFT分析显示0 - 5000赫兹的频率谱中保存的psb3phpwm3level_str结构信号。FFT将每在一个窗口开始形成在t = 0.1 - 2 / 60。选择输入标记的VAA _inverter”。点击显示，观察最后2个周期的频谱。 为0 - 5000赫兹的频率范围内的vaa_inverter和THD的基波分量的频谱窗口上显示。因为在IGBT的正向压降和二极管，逆变器的基波电压的大小略低于理论值。正如预期的一个双逆变器，第一次谐波发生在M对载波频率的双ultiples。 The same circuit using two-level inverters in twin configuration is available in the psb3phPWM model. Run this model and compare the harmonic contents in the 2-level and 3-level inverter voltage for the same modulation index (m = 0.85). Harmonics occur at the same frequencies but their magnitude is approximately two times lower for a 3-level inverter. 该电路采用两电平逆变器双配置在psb3phpwm模型是可用的。运行此模型比较两级为三电平逆变器电压的谐波含量他相同的调制指数。谐波发生在相同的频率，但其规模降低约两次三电平逆变器。