SGER: A DSP Based Active Power Filter to Cancel Harmonic Currents in Low Voltage Electric Power Distribution Systems

由于越来越多地使用非线性负载，典型的低压配电系统正日益受到过量谐波电流的污染。由此产生的电力“污染”，经常沿着配电馈线传播数英里。更多公开的问题案例是由大型单一污染源引起的，如电弧炉和兆瓦级调速驱动系统。这些情况已由电力公司逐案处理。然而，由于成千上万的小型住宅、商业和工业非线性负荷的聚集而产生的累积问题则更加难以处理。因此，有必要在最终用户设施和配电馈线上安装新的和创新的电路，以减少谐波失真。本研究提出一种基于数位讯号处理器（DSP）的有源电力滤波器，以消除低压配电系统中的谐波电流。近年来，dsp已成为实现测量和控制算法的一种有吸引力的手段，主要是因为与控制应用中使用的传统微处理器相比，它们的计算速度快，成本低。提出的研究目标是：开发一种基于DSP的单相有源电力滤波器的控制算法，以消除低压配电系统中的谐波电流。在实验室样机上对该算法进行了实验验证。验证了基于dsp的有源电力滤波器能够为配电系统中的谐波问题提供局部低成本的解决方案。鉴于与公用事业系统连接的电力电子设备的激增，各个国家和国际机构一直在考虑限制谐波电流注入以保持良好的电能质量。修订后的IEEE-519-1992标准规定了用户和公用事业公司的要求。因此，所提出的研究将为服务于公用事业公司和消费者的利益做出重大贡献。本项目提出的基于dsp的单相有源电力滤波器在隔离和中和一组单相非线性负载（如计算机和其他电子办公设备）产生的谐波方面有重要贡献，从而保护上游配电系统。这将提供一种本地化的低成本解决方案，而且重量轻，占用空间最小。与现有方法相比，采用基于DSP的控制器将显著提高系统性能。DSP的数字控制将提供快速的瞬态响应，高性能和更高的可靠性，以及计算能力和抗噪声和漂移等固有优势。此外，基于dsp的控制器可编程，可以很容易地升级或修改，以满足特定的系统要求。

ECS-9712596 Shireen Typical low voltage electric power distribution systems are increasingly being contaminated with excessive amounts of harmonic currents due to the growing use of nonlinear loads. The resulting electrical "pollution", often propagates for miles along the distribution feeders. More publicized problem cases have been caused by large single source offenders such as arc furnaces and megawatt-sized adjustable speed drive systems. These situations have been handled by electric utilities on a case by case basis. However, cumulative problems because of the aggregation of thousands of small residential, commercial and industrial nonlinear loads are much more difficult to deal with. Thus, there exists the need for new and innovative circuits that can be placed at end user facilities and on distribution feeders to reduce harmonic distortions. This research project proposes a Digital Signal Processor(DSP) based active power filter to cancel harmonic currents in low voltage electric power distribution systems. In recent years, DSPs have become an attractive means for the implementation of measurement and control algorithms, mainly because of their computing speed and low cost compared to conventional microprocessors used in control applications. The objectives of the proposed research are: To develop a DSP based control algorithm for a single phase active power filter to cancel harmonic currents in low voltage electric power distribution systems. To experimentally evaluate the algorithm on a laboratory prototype. To verify that the DSP-based active power filter is capable of providing localized low cost solution to the harmonic problem in power distribution systems. In view of the proliferation of power electronics equipment connected to the utility system, various national and international agencies have been considering limits on harmonic current injection to maintain a good power quality. The revised IEEE-519-1992 sta ndard, specifies requirements for the users as well as for the utility companies. Therefore, the proposed research will make significant contributions that serve the interests of the utility companies as well as the consumers. DSP-based single phase active power filters as proposed in this project can have significant contribution in isolating and neutralizing harmonics generated by a group of single phase nonlinear loads (such as computers and other electronic office equipment) and thereby protecting the upstream distribution system. This would provide a localized low cost solution, that will also be light in weight and occupy minimum space. The use of a DSP based controller will improve the system performance significantly compared to existing methods. Digital control by a DSP will provide fast transient response, high performance and increased reliability, in addition to the inherent advantages like computational power and immunity to noise and drift. Also, being programmable the DSP-based controller can easily be upgraded or modified to meet specific system requirements.