【作者】 金舜；

【导师】 钟彦儒；

【作者基本信息】 西安理工大学 ， 电力电子与电力传动， 2007， 博士

【摘要】 本文在对二极管箝位三电平SVPWM算法充分论证的基础上，提出一种无电流传感器的中点电位控制和窄脉冲消除方法，并同时进行了死区的补偿。仿真和实验结果表明，该方法实现简单，输出波形谐波含量小，中点电位得到很好的控制，同时解决了窄脉冲问题。由于同时进行了死区补偿，使逆变器在低频输出时波形明显改善。在用TMS320LF2407A DSP为平台的二极管箝位三电平实验样机上取得了良好的效果。 抽象出开环无载波PWM过调制策略的设计指导思想，并以此为指导提出了4种新的过调制策略。其中SMN1方法极简单，并能够精确地控制输出电压的基波大小。将双模式极限轨迹的过调制方法推广到单模式(SMLT)，获得了在全部非线性区参考电压矢量的以调制度为变量的一种统一解析式，利用该解析式能够由调制度直接计算出使得输出基波准确跟踪给定所需的参考电压矢量，无论对于实践还是理论研究都是有重大的意义。对文献中已有的5种和本文新提出的4种共9种开环无载波PWM过调制策略进行了统一的分析和比较。将这9种过调制方法推广应用于二极管箝位三电平SVPWM，并在二极管箝位三电平平台上通过了全部方法的实验验证。 提出利用PWMVECTOR矩阵进行与PWM波形谐波有关的精确数值计算。对PWM波形的评价指标体系进行了系统的研究。指出WTHD指标的物理含义实际上直接反映谐波电流的总畸变率。推广了加权THD的概念，提出了反映电机谐波损耗的新指标LWTHD，并提出了WTHD指标集的概念。最后提出了反映谐波转矩的新指标TTHD。 利用谐波解析表达式和数值计算对HDDF的合理性与普遍性进行了阐释，找到了WTHD与HDDF的解析关系。指出当开关频率足够高时，PWM波形的频谱满足“迁移”和“聚散”特性，就可以使用HDDF从谐波电流的角度对PWM方法做出评价和比较。 用本文开发的谐波数值计算方法计算了本文的三电平SVPWM方法所产生的PWM波形的除了TTHD以外的所有指标，并与两种典型的两电平PWM波形进行了指标比较。 利用HDDF指标对本文的三电平SVPWM方法和两种典型两电平PWM方法进行了定量的比较和分析，最后给出了不同方法在相同条件下的开关频率对应关系。更多还原

【Abstract】 On the basis of sufficient argumentation of the three-level SVPWM algorithm, a neutral-point potential balancing with narrow-pulse elimination algorithm without current sensor is proposed, and dead time is compensated at the same time. The result of simulation and test verified that this algorithm is simple to be carried out, harmonics in output waveform are small, neutral-point potential can be controlled fairly well, and narrow pulse problem is solved as well. Furthermore, output torque is strengthened in low frequency for the successful dead-time compensation. All of these were achieved on a diode-clamped three-level model inverter developed with TMS320LF2407A DSP.The directed ideal for designation of feed-forward carrier-less PWM over-modulation is abstracted. On the basis of this ideal, 4 new over-modulation schemes were developed. Among of them, SMN1 is the simplest one and characteristic of accurate control of fundamental component of output. Over-modulation based on two mode limit trajectory method is extended to single mode. And by doing this, a uniform expression for calculation of reference vector, which can produce an output with the desired fundamental component, is obtained in the whole nonlinear region. This is valuable for both practice and theory. 9 over-modulation schemes, 4 of which are developed by this paper, were analyzed and compared uniformly. All of these 9 schemes were extended to diode-clamped three-level inverter, and experiment was carried out on it.Methods for accurate calculation of various index associated with harmonic characteristic of PWM waveform is developed with PWMVECTOR matrix. Indexes for evaluation of PWM waveform are studied systematically. A fact that the physical meaning of WTHD is just current THD is point out. By extending the ideal of WTHD, new harmonic-loss reflecting index LWTHD is brought forward. In addition, a new harmonic-torque reflecting index TTHD is brought forward too.The reasonable and universality of HDDF are explained with the aid of analytical expression and numerical calculation of harmonic of PWM waveform, and the relationship between HDDF and WTHD is find. It is clarified that PWM method can be evaluated and compared with regard to harmonic current if only the frequency spectrum satisfy the "shift" and "disperse" phenomenon.All of indexes mentioned in this paper except TTHD are calculated for the developed three-level SVPWM, and the result is compared with that of two popular two-level PWM methods.The three-level SVPWM method is compared with two popular two-level PWM methods with the aid of HDDF, and the relationships of switching frequency of them under same condition are calculated.更多还原