基于DSP的有源电力滤波器的研究与设计

发布时间：2018-12-26 07:03

【摘要】：在现代生活中，电力电子技术的不断发展给人们的生活带来了方便的同时，电力电子技术的应用也使得的电能质量的问题日益突出。由于电力电子设备中存在大量的非线性电感、电容等器件，在这些非线性负载使用时会产生的大量谐波及无功电压、电流。在设备并入电网后会使得电网电压、电流产生畸变以及降低电网利用率，不仅对电网的危害极大，同时也使用户的用电成本大大增加。于是电力滤波器便应运而生。起初的LC滤波器动态性能较差不能滤除变化的谐波且易与电网中某次谐波发生谐振，使得谐波放大后流入电网，从而加重了电网的畸变。相对于LC滤波器，有源电力滤波器克服了以上缺点，具有很好的动态性能，同时避免了发生谐振的可能。因此有源电力滤波器得到了越来越多的关注与研究。本文以并联电压型有源电力滤波器作为主要研究对象，对其工作原理进行了详细的论述，有源电力滤波器系统可以分为指令电流的检测和补偿电流的跟踪控制两部分。首先，对指令电流检测的方法进行了详细研究。以基于瞬时无功功率理论的指令电流检测算法作为本文检测算法，着重研究了在此算法基础上的p-q法、i_p-i_q法在各种环境下的适用性。在分析结果中可以看出i_p-i_q法不仅适用于电网电压畸变、不对称的情况，而且在三相四线制同样适用。基于瞬时无功功率的i_p-i_q法的适用性较广，故本文以此方法作为指令电流的检测方法。然后，在有源电力滤波器的补偿电流跟踪控制方面，本文采用的控制方法为基于空间矢量的无差拍控制。本文首先分析了滞环比较控制、三角波比较控制与电压空间矢量控制（SVPWM）各自的优缺点。相对于滞环比较控制、三角波比较控制，SVPWM算法开关频率固定，主电路直流侧电压利用率相比较于其他两种算法提高了1500，相当于减小了直流侧电容的体积，节约了成本，同时易于数字化实现。鉴于并联电压型有源电力滤波器自身的特点，有源电力滤波器与电网之间通过电感相连，于是在生成PWM信号的过程中会存在一个微分方程，直接此求解微分方程很难实现，对此问题本文采用了无差拍控制预测的方法，将微分方程离散化，，通过预测下一时刻的指令电流来求解此微分方程。以上述理论研究为基础，本文以基于瞬时无功功率的i_p-i_q法作为指令电流的提取方法，采用基于SVPWM的无差拍控制实现补偿电流的跟踪控制，设计了一套10KVA的有源电力滤波器（APF）系统。主要包括系统主电路设计、以DSP(TMS320F2812)作为系统控制芯片的控制电路设计及控制系统软件设计。此外利用MATLAB软件建立了系统仿真模型，仿真结果表明本设计系统谐波和无功电流补偿效果良好。
[Abstract]:In modern life, the continuous development of power electronics technology has brought convenience to people's life, at the same time, the application of power electronics technology also makes the problem of power quality more and more prominent. Because there are a lot of nonlinear inductors capacitors and other devices in power electronic equipment a large number of harmonics reactive voltage and current will be produced when these nonlinear loads are used. After the equipment is merged into the power network, the voltage and current will be distorted and the utilization ratio will be reduced, which will not only do great harm to the power network, but also increase the cost of electricity consumption. So the power filter came into being. The initial LC filter has poor dynamic performance and can not filter the varying harmonics, and it is easy to resonate with a certain harmonic in the power network, which makes the harmonic amplification flow into the power network, thus exacerbating the distortion of the power network. Compared with the LC filter, the APF overcomes the above shortcomings, has good dynamic performance and avoids the possibility of resonance. Therefore, active power filter (APF) has been paid more and more attention and research. In this paper, the shunt voltage active power filter is taken as the main research object, and its working principle is discussed in detail. The active power filter system can be divided into two parts: the detection of the instruction current and the tracking control of the compensation current. Firstly, the method of instruction current detection is studied in detail. Taking the instruction current detection algorithm based on instantaneous reactive power theory as the detection algorithm in this paper, the applicability of p-q method and i_p-i_q method in various environments are studied. It can be seen from the analysis results that the i_p-i_q method is not only suitable for the voltage distortion and asymmetry of the power system, but also applicable to the three-phase four-wire system. The i_p-i_q method based on instantaneous reactive power is widely used in this paper. Then, in the aspect of compensating current tracking control of active power filter, the control method adopted in this paper is deadbeat control based on space vector. In this paper, the advantages and disadvantages of hysteresis comparison control, triangular wave comparison control and voltage space vector control (SVPWM) are analyzed. Compared with hysteresis comparison control and triangle wave comparison control, the switching frequency of SVPWM algorithm is fixed. Compared with the other two algorithms, the DC side voltage utilization ratio of the main circuit is increased by 1500, which is equivalent to reducing the volume of the DC side capacitance and saving the cost. At the same time, it is easy to realize digitally. In view of the characteristics of shunt voltage-type active power filters, the active power filters are connected by inductors to the power network, so there will be a differential equation in the process of generating PWM signals, and it is difficult to solve the differential equations directly. In this paper, the differential equation is discretized by using the prediction method of non-beat control, and the differential equation is solved by predicting the command current at the next moment. On the basis of the above theoretical research, the i_p-i_q method based on instantaneous reactive power is used as the command current extraction method, and the compensation current tracking control is realized by using the non-beat control based on SVPWM. An active power filter (APF) system based on 10KVA is designed. It mainly includes the design of the main circuit of the system, the design of the control circuit with DSP (TMS320F2812) as the chip of the system control and the design of the software of the control system. In addition, the simulation model of the system is established by using MATLAB software. The simulation results show that the harmonic and reactive current compensation effect of the designed system is good.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM761;TN713.8

【参考文献】