APF Module Active power filter(APF)
Active power filter(APF)is a new generation of power quality control equipment,APF is mainly used for harmonic control. Our company wholeheartedly solves the power quality problem for the user, the active power filter has the unprecedented comprehens
Active power filter(APF)is a new generation of power quality control equipment,APF is mainly used for harmonic control.
Our company wholeheartedly solves the power quality problem for the user, the active power filter has the unprecedented comprehensive power quality management ability, the apf can simultaneously filter the harmonics within 2-50 times, the filter ability may be as high as 97%, The harmonic compensation time of step change is less than that of 10ms.apf, and the efficiency of the whole machine is more than 97.5. it is suitable for all kinds of situations in industry and civil field, and is the best solution for nonlinear load harmonic treatment and reactive power compensation.
By setting the parameters, the device can simultaneously filter harmonics, dynamically compensate reactive power, compensate three-phase imbalance, compensate voltage drop and so on.。
◆Harmonic filtering principle
Apf collects the current signal in real time through external current transformer, separates the harmonic part through the internal detection circuit, and generates the compensation current opposite to the harmonic magnitude in the system by igbt power converter.The function of filtering harmonics isrealized.
The APF output compensation current varies dynamically according to the harmonic volume of the system, so there is no problem of overcompensation. In addition, there is a overload protection function inside the APF. When the system's harmonic volume is larger than the filter capacity, the device can automatically limit the outputof the rated capacity at 100%, and itwill not overload.
APF nternal control principle
in order to prevent the power grid from striking the DC bus capacitor at a moment when the switch is switched on, the capacitor of the DC bus is first charged by the soft resistance, which lasts for several decades. When the bus voltage udc reaches a predetermined value, the main contactor is closed. DC capacitor is used as energy storage device, which provides energy through igbt inverter and internal reactor to output compensation current. APF collects current signal from outside ct in real time to signal conditioning circuit, and then sends it to controller The controller separates the fundamental wave components, extracts all harmonic current, reactive current, three-phase unbalanced current, and compares the current components to be compensated by apf to get the difference. As a real-time compensation signal output to the drive circuit, the trigger igbt converter injects the compensation current into the power network, realizes the closed-loop control and completes the compensation function.
APF Dynamic and steady-state characteristics
Apf is particularly noteworthy for its superior dynamic and steady-state characteristics. The following diagram shows the dynamic characteristics of apf when the load changes and the steady-state characteristics at full load.
APF product features
1. Modular design, any module failure will not affect the normal operation of other modules, greatly improve the reliability of the whole machine equipment;
2. Modular design, any module failure will not affect the normal operation of other modules, greatly improve the reliability of the whole machine equipment;
3. Filtering, compensating reactive power, compensating three-phase imbalance can be singled out or multi-selected, and can set the priority of function;
4. Using sliding window iterative dft detection algorithm, the calculation speed is high, the instantaneous response time is less than 0.1 Ms, and the compensation full response time is less than 10 Ms.
5. Sampling can be made on the load side or on the grid side at the site ct connection position.
6. It can be connected in parallel with any LC passive equipment in the field withoutresonance.
7. a reliable limit flow control link is adopted. When the compensation current in the system is larger than the capacity of the active filter, the device can automatically limit the current to 100% capacity, maintain normal work, and do not appear to be overloaded and burned.
8. The main circuit adopts the three-level structure of the three-bridge arm. The output waveform is of high quality and the switching loss is low.
using high clarity 7 Inch Touch screen, the operation is convenient, the screen real-time display system and device run parameters, with fault alarm and recollection function, using FPGA as control chip and DSP chip to do algorithm processing, parallel operation, the operation rate is far higher than the single DSP control mode, the communication delay is small, the response speed is faster, and FPGA after the sintering program It is equivalent to hardware circuit, strong anti-interference ability, no failure of program running.
9. For users save space 600 mm wide cabinet with the maximum power of 450 a / 300 kvart 800mm wide cabinet can reach 900a / 600kvara, reaching the first in the industry;
10. The input end of the active filter