Main features of active filter

(1) The working principle of active power filter

Active power filter is mainly composed of load current separation, command current regulation, output current control, drive circuit and main circuit. It uses a current-type converter and connects the reactor to the system. By adjusting the instantaneous amplitude and phase of the AC-side inverter output voltage, or directly controlling the AC-side output current, the device emits or absorbs broadband reactive power. The active power filter device based on power electronics is connected in parallel in the power grid, which is equivalent to a controllable reactive and harmonic current source. Its reactive and harmonic current can quickly follow the change of load reactive current, automatically compensate the reactive and harmonic power required by the power grid system, and can realize the full range of compensation from inductive reactive to capacitive reactive power, and at the same time adjust the power grid voltage dynamically and stably.

(2) the working principle of active power filter

The active power filter adopts modular plug-in design, which integrates the functions of three-phase imbalance control, harmonic resistance and reactive power compensation, which is convenient for operation and maintenance personnel to install and disassemble, and also facilitates the expansion of compensation capacity for future changes in electricity load.

The main features of the active filter device are as follows:

1) The compensation method is flexible: it can not only make up harmonics, but also make up reactive power. It can make full compensation for 2-51 harmonics or specify specific harmonics to compensate, and at the same time can control the three-phase imbalance problem;

2) Linear compensation, full response time ≤ 5ms;

3) It has a humanized human-computer interaction interface, through which the real-time power quality information of the system and the body can be seen, the operation is simple, and it can be controlled by remote or local control;

4) DSP high-speed detection and operation of digital control system and imported IGBT, high power density, high reliability;

5) monitoring and display with remote communication interface, real-time monitoring through the PC;

6) Standard modular design, shorten the delivery cycle, while improving the reliability and maintainability of use.

Active power filter can be installed by wall hanging and whole cabinet, and can realize centralized and local management. The product shown in Figure 2 brings convenience to installation, maintenance and future upgrade, and improves the overall installation efficiency.