Active power filter APF (Active Power Filter, called APF) is a dynamic harmonic suppression, new compensation reactive power electronic devices, it is possible to change the size and frequency of harmonics and change reactive power compensation. Only fixed is called active, as the name suggests the device power supply is needed (for harmonic compensation of the main circuit), the application can overcome the traditional LC filters harmonic suppression and reactive power compensation method disadvantages (traditional compensation), to achieve dynamic tracking compensation, and can both complement and supplement harmonic reactive; three-phase circuit instantaneous reactive power theory is the main basis for the development of the theory of APF; APF has parallel and series two, the former with more ; shunt active filter is mainly governance harmonic current series active filter control voltage problem is mainly caused by harmonics. Active Filter comparison with passive filters, the treatment effect is good mechanical and electrical engineering sales, the main can filter out many times and higher harmonics, does not cause resonance, but the price is relatively high! Low Voltage APF active power filter device works: Low active power filter APF system is a dynamic harmonic filter and dynamic reactive power compensation system of new power electronic devices. Three-phase parallel converter which consists of IGBT tubes via a series reactors in parallel in the power line, the load current collected APF control system through the current transformer, through real-time detection circuit load current harmonic component and the fundamental reactive component separated by the control system fast computing electrical engineering, using the latest technology to trigger PWM control of the IGBT. By the large-capacity three-phase IGBT tubes in parallel converter compensating current injected into the system, the compensation current and load current harmonic currents are equal in magnitude and opposite the construction of electrical and mechanical engineering, offset each other to achieve a harmonic filter function ensure that the final flow into the system current is a sine wave. In addition, if the user has filtering and reactive power compensation synchronization is complete requirements, APF only way to change the setting mechanical and electrical engineering and maintenance, we can achieve harmonic filtering and reactive power compensation to improve the power factor, improve power quality purposes . Construction of electrical and mechanical engineering | Xi Connaught Electrical and Mechanical (certified) | Mechatronics Engineering study by Connaught Electrical and Mechanical Equipment Co., Ltd., Henan. Henan Xi Connaught Electrical Equipment Co. (www.hnxinuo.com) is Zhengzhou, electronics, electrical products processing leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In practice Connaught Electrical and Mechanical leadership with the staff warmly welcome all inquiries negotiations to create learning Connaught Electrical and Mechanical better future.