Product  introduction     

　With the wide application of power electronic technology, now all kinds of load is mostly nonlinear loads, such as the extensive use of various rectifier equipment, frequency converter, electric arc furnace, etc. in chemical industry, metallurgy, steel, coal mines and traffic department, as well as lighting appliances, entertainment facilities, UPS, computer, elevators, air conditioning, photocopiers, etc., which will generate a large number of harmonic current and inject into the power grid, making the grid voltage distortion, also this "harmonic pollution" will bring more and more influence and harm on the grid and the user. The nonlinear load increases much faster than the speed of the power grid construction. Power quality problems gradually transit from a pure reactive problem to the mixed problem of harmonics and reactive. The traditional capacitance compensation device and the filtering device are no longer suitable for the change of load nature. And they even become the object of harmonic impact and a weak link of the system for their poor governance effect.      

Sifang Sanyi G series active power filter is developed for the industrial application of the reactive power compensation and power filter. Based on the research and development strength of North China Electric Power University, G series active power filter has been widely used in communications, energy, manufacturing, tobacco and other industries, and has received good evaluation by customers in recent years.

Working  principle       

　Active Power Filter (APF, the Active Power Filter) connected to the power grid in parallel way, through the real-time detection of load harmonics and reactive component, using PWM transformation technology, inject current that is equal and opposite to harmonic and reactive component into the power distribution system to realize the function of harmonic suppression and dynamic reactive compensation.      

　Active filter is a harmonic current source, and its access won't impact on the system impedance, even when the power supply or utilization system structure and impedance changes, it won’t have the risk of resonance and won’t affect compensation performance; at the same time there will be no problem of overload. When the system harmonic current increases over the compensation ability of the device, filter can still play the largest role in compensation;

Technical features      

1、Filter 2nd ~25th harmonics, and filter more than 8 kinds of harmonics at the same time.

2、Response time<300μs，complete response time<10ms

3、 Filter property is not affected by the system impedance to eliminate the risk of resonance with system impedance.  

4、 The system has rapid and complete fault self-check function.

5、Set harmonic number and harmonic filtering target as required.

6、Built-in reactive compensation function, which can be selected.

Application fields     

　　G series active power filter can be widely used in power distribution network group of industrial, commercial, office. For example: electrolytic plating, power system, petrochemical enterprise, high-rise buildings, airports, ports, medical and other industries.

Apply to industrial load of three-phase three-wire system products. (3Ltype)

Intermediate frequency furnace, electric arc furnace

 Automobile manufacturing

 Rail transit

 Chemical & pharmaceutical

Technical highlight      

1.Advanced control strategy       

　G series active filter adopts closed loop control strategy, combining the original self-adaptive current control algorithm. As a result of the switch frequency controlled by the average current is constant, the system overcome the weakness of the traditional hysteresis control that the wide range of output spectrum, filtering difficult, high frequency harmonic brought by the changes of the switch frequency will interfere power grid, thereby the APF has achieved excellent filtering performance. When APF is full load , the THDI of system source side < 3%, 2/3 load THDI < 3%, while half load THDI < 4%

2.Adopt unique LCL filter topology structure       

（1）Due to the good filter performance of the LCL topology, when APF compensates, the high harmonics generated by the IGBT high frequency switch will not be injected into power grid, and the compensation effect is better.

（2）Applied to any site grid system impedance and the resonance will not occur to ensure the safety of the device.

3.Single FPGA control system for centralized control      

　　The system adopts Spartan3adsp FPGA of Xilinx Company for centralized control. The clock frequency of FPGA can reach to 200 MHZ with 84 internal hardware DSP units, which run in parallel, so the arithmetic speed is higher than that of single DSP control mode. With small communication latency and the fast response, it is easy to use more advanced control algorithm, thus the G series APF can achieve more excellent filtering compensation effect.

4.The unique structure of the parallel operation     

　　G series APF can adopt the structure of 10 devices in parallel and use only one FPGA centralized control, overcome the communication delays of multiple controllers and the shortcomings of possible disturbance, enhance the compensation performance of APF, improve the reliability of the system.

5.Key components are imported with original packaging       

(1) IGBT module: original import IGBT module

(2) The DC bus capacitor: film capacitor

Specifications and models      

Naming rules of the specifications

            

Specification of GAPF series products as follows：

3L low voltage APF

400V：

GAPF-50/0.4-F-1-001

GAPF-100/0.4-F-1-001

GAPF-150/0.4-F-1-001

GAPF-200/0.4-F-1-001

GAPF-300/0.4-F-1-001

600V：

GAPF-300/0.6-F-1-001

GAPF-300/0.6-S-2-001

GAPF-600/0.6-F-1-001

GAPF-600/0.6-S-2-001

Ps: According to the customer needs, we can produce other currents level of active power filter products

Performance parameter

Effect test

First channel CRT1 is system side current

Second channel LA1 is APF current

Third channel LA2 is load side current

Specification and dimension

 Application field

Send 50-600A compensation current, suitable for non-linear load with different capacity of 380V, 600V voltage grade power distribution network. For example, in the industry like building, oil drilling, medical treatment, communication, factory, etc. contains multiple types of non-linear load, like UPS, frequency converter, battery charger, office facilities, elevator, air-conditioner, etc.

Model selection

suitable for three phase three wire system

Determine compensating current through test data. Or calculate compensating current through power distribution system detailed information(transformer, load condition)

three phase three wire system should collocate 2 CT(used for A, C three phase)

Compensating plan

 Plan summary

According to different distribution of non-linear load of power distribution system and governance effect needed to achieve by the customer, the applications of G series APF are mainly centralized compensation, partial compensation and on-site compensation.

Centralized compensation

Centralized compensation applies to power distribution system with many load types. Non-linear load is large and decentralized, in addition, single unit  non-linear load harmonic content is small, so G series APF can be installed in power grid low voltage inlet terminal to make comprehensive treatment for harmonics in power distribution system.

 Partial compensation

Partial compensation applies to the power distribution system of which non-linear load concentrated in a few branches. Install G series APF at summary point of these branches to ensure that the harmonic current does not flow into the grid and contaminate other loads.  

Local compensation

Local compensation applies to the power distribution system with large single unit harmonic content and decentralized distribution. Install G series APF at load input side to reach ideal treatment effect.