Chengji Intelligent Electrical Power Filter

Basic Introduction of CJAPF Low Voltage Active Power Filter

Active power filter (APF) is a power electronic device based on IGBT power converter used for dynamic filtering of harmonics and dynamic compensation of reactive power. APF real-time detects various harmonics and reactive power in the power grid, and dynamically tracks and compensates for them, thus being able to compensate for harmonics and reactive power that vary in amplitude and frequency. APF overcomes the shortcomings of traditional passive filters, such as poor filtering effect, easy resonance, and only able to compensate for fixed subharmonics. It can effectively filter and compensate for various fast transient impact loads.

The CJAPF series active filters adopt a closed-loop control method, combined with a unique adaptive control algorithm, which enables APF to achieve good filtering performance under both full load and light load conditions; The CJAPF series active filters adopt the current average control method combined with the LCL topology structure, overcoming the traditional hysteresis current control that injects harmonics generated by IGBT high-frequency switches into the power grid due to changes in switching frequency.

　　Characteristics and Applications of CJAPF Power Filter

　　Application Fields and Characteristics of CJAPF/3L

CJAPF/3L active power filter suitable for industrial large capacity loads

For industrial high-capacity nonlinear loads such as rectifiers, frequency converters, large UPS, intermediate frequency furnaces, electric arc furnaces, welding machines, etc., Shanghai Chengji Electric has launchedCJAPF/3L series active power filters.

The CJAPF/3L series active power filter has excellent filtering ability, which can simultaneously filter out 2-50 harmonics. The filtering ability can reach over 97%, and the complete compensation time for step changing harmonics is less than 10ms.

The CJAPF/3L series active power filters can operate in parallel with multiple units, making them fully suitable for various situations in the industrial field. They are an excellent solution for harmonic control of large capacity nonlinear loads in industrial applications.

　　Application Fields and Characteristics of CJAPF/4L

CJAPF/4L active power filter suitable for nominal use

Fluorescent lamps, computers UPS、 Elevators, variable frequency air conditioners, and other devices not only seriously pollute the power grid, but also generate third harmonics that superimpose on the neutral line, causing it to heat up and posing a serious threat to the safety of the power distribution system. In response to commercial hybrid loads, Shanghai Chengji Electric has launchedCJAPF/4L series active power filters.

CJAPF/4L can completely eliminate the neutral line current caused by the third harmonic, and can eliminate all or selected harmonics within the range of 2-50. It has communication function and can be easily connected to the user's existing communication system.

The CJAPF/4L active power filter can operate in parallel with multiple units, making it fully suitable for various situations in the civil field. It is an essential electrical equipment in commercial building distribution systems and other civil fields.

·Elevator and lifting system · Rubber industry · Sewage treatment system · Automotive industry

·Paper industry, cement industry, computer, welding machine system

·Petrochemical industry · Variable frequency drive equipment · Tunnel ventilation · Intelligent buildings

·UPS, tobacco industry, wind power plants, shipbuilding industry, etc

·Mines, hotels, hospitals, and rail transit

　　Working principle of APF electrical power filter

After the input switch is closed, CJAPF charges the DC capacitor through a current limiting resistor. When the DC bus voltage reaches the rated value, the charging contactor closes and the device starts working.

DC capacitors are energy storage components and output compensation current to the grid through IGBT inverters and interface reactors; The DC capacitor simultaneously provides working power to the signal board, control board, and driver board through the power board.

CJAPF measures load current or grid current through external CT and sends it to the signal board for processing. The control board completes the calculation of load harmonic current and closed-loop control of harmonic current compensation, and generates PWM drive signals to the drive board. The drive board drives the IGBT of the inverter to output the required compensation current to the grid, completing the function of harmonic filtering.