Active Power Filter (APF)

APF Principle

Delta’s PQC Series APF is connected in parallel with non-linear loads, and uses one set of current transformers (CT) to detect the load current. It calculates each order harmonic current by FFT algorithms in its DSP microchips, and then generates a compensating current with the same amplitude but opposite phase angles to the detected harmonic current, which cancels out the original load harmonics.

The PQC series APF not only eliminates harmonic current from the load side, but it also mitigates harmonic voltage caused by harmonic currents. The APF system can also improve power factor (PF) and correct load imbalances in the power system.

Note: CT is a critical part of the APF system, and it can be purchased by users themselves, following Delta’s suggestions on CT specification.

PQC APF Principle

APF Structure

Delta PQC Series APF has a modular design, which adopted 3-level inverter topology with 3 pcs modular IGBT and DC capacitor components, and the Delta Active Power Filter system consists of one or several APF modules and a 7'' or 10'' HMI display.

Each APF module is an independent harmonic filtering system, and users can change the harmonic filtering system rating by adding or removing APF modules.

According to the mounting type, Delta PQC series APF can be divided into Modular APF (rack mounting) and wallmounted APF.
 

Product Introduction

Solutions
APF Module and Cabinet Solutions

According to cable terminal type, a modular APF can be divided into two types:
  • Drawer type modular APF (adding pluggable accessories on power cable terminals)
  • Mixed fixed type modular APF(Power cables are fixed from rear side, Signal cables are fixed from front side.)

HMI has two types:
  • 7’’ HMI
  • 10’’ HMI

APF modules and HMI panel can be embedded in Delta’s standard APF cabinet or a customized cabinet. There are breakers, cable terminals and Surge Protection Device (SPD) in the APF cabinet. Delta can supply IP30, IP42, IP54 or customized solutions.


APF Module and Cabinet Solutions

Wall-mounted APF Solutions

Delta’s Wall-mounted APF can be installed on a wall, which is suitable for low rating applications, and wall-mounted type HMI can be installed on the wall-mounted APF module, along with a mounting bracket to provide support and protection. Delta can supply IP30, IP42, IP54 or customized solutions.

Active Power Filte Wall-mounted Solutions
Features & Benefits
  • Multifunctional: Harmonic, reactive power and imbalance compensation
  • Harmonic Elimination Range: 2nd~50th order (Selectable)
  • High harmonic filtering rate: Up to 98%
  • Excellent reactive compensation: High speed, Precise (-0.99 ≤ PF ≤ 0.99), Step-less, Bi-directional (capacitive and inductance) compensation
  • Excellent imbalance correction: Both negative and zero sequence, mitigates neutral current
  • Wide input voltage & frequency range, adapts to tough electrical environments
  • Low thermal loss and high efficiency
  • High stability: Infinite impedance to grid, avoids harmonic resonance problems
  • Flexible application: Modular design, embedded in standard or customized cabinet
  • Easy installation and maintenance: Plug-in installation for APF module replacement and expansion
  • Wide capacity range: 30~750 A for a single cabinet, up 10 cabinets in parallel
  • Environmental adaptability: -10~55°C ambient temperature, compatible with diesel generator
  • Complete protection: Grid Over/Under voltage, APF over current, over temperature, and more. All faults are recorded in the event log, which is convenient for failure analysis
  • Waveform display function on HMI: Display waveform of input Voltage, Grid current, Load current and APF current
  • Display Harmonic current Histogram on HMI: Grid harmonic current and load harmonic current
  • CTs’ reversal auto correction can be setted on HMI, support grid side or load side current detection
Specifications

Mixed Fixed Type Products

 
  1. Rated Voltage: AC 208 V, AC 400 V, AC 690 V
  3. Electrical Specification
  4. Input Voltage Range
    AC 208 V: AC 166~250 V, AC 166~250 V
    AC 400 V: AC 308~456 V, AC 308~480 V
    AC 690 V: AC 384~880 V
  5. Electric Connection
    AC 208 V: 3P4W, 3P3W
    AC 400 V: 3P4W, 3P3W
    AC 690 V: 3P3W
  6. Rated Current per Module
    AC 208 V: 50 A, 75 A, 100 A, 150 A
    AC 400 V: 30 A, 50 A, 75 A, 100 A, 150 A
    AC 690 V: 100 A
  7. Rated Current per Cabinet
    AC 208 V: 50~750 A (Module combination)
    AC 400 V: 30~750 A (Module combination)
    AC 690 V: 100~500 A (Module combination)
  8. Rated Frequency: 50(60) Hz ± 10%
  9. Input Voltage THD Range: ≤ 15%
  10. Redundancy: Each module is an independent filtering system
  11. Harmonic Elimination Range: 2nd~50th order (Selectable)
  12. Harmonic Filtering Degree: 0~100% programmable per harmonic in Ampere value
  13. Harmonic Filtering Performance: Filter up to 98% harmonics at rated load, THDv < 3%, THDi < 5% after filtering
    (Precondition: The grid background THDv shall be less than 1% under no-load condition.)
  14. Reactive Power Compensation Capability: Both inductive and capacitive reactive power
  15. Reactive Power Compensation Performance: Cosφ ≥ 0.99 after compensation (If the APF capacity is sufficient)
  16. Imbalance Correction Capability: Mitigate negative and zero sequence
  17. Full Response Time: < 10 ms
  18. Instant Response Time: < 100 us
  19. Thermal Loss
    AC 208 V: ≤ 5% of APF rated capacity
    AC 400/690 V: ≤ 3% of APF rated capacity
  20. Output Current Limitation: Automatic (100% rated capacity)
  21. Parallel Expansion (System): Up to 10 Racks (7 modules per cabinet)
  22. MTBF: > 100,000 hours
  24. Control Technology
  25. Switching Frequency: 30 kHz
  26. Controller: DSP + FPGA
  27. CT Position: Grid side or Load side
  28. Waveform Display: Input Voltage waveform, Grid current waveform, Load current waveform and APF current waveform
  29. Harmonic Current Histogram Display: Grid harmonic current and load harmonic current
  30. Communication: Modbus RTU (RS-485), Modbus TCP/IP (Ethernet)
  32. Physical Specification
  33. IP Grade of Cabinet: IP20, IP30, IP54, IP55 or customization
  34. Cooling Method: Intelligent forced air cooling
  35. Noise Level
    AC 208 V/ AC 400 V: < 65 dB(A) @1 m (Module)
    AC 690 V: < 70 dB(A) @1 m (Module)
  36. Dust Filter: Optional
  37. Dimension: Please download the brochure and refer to APF model table
  38. Weight: Please download the brochure and refer to APF model table
  40. Environmental Requirement
  41. Ambient Temperature: -10~50°C 
  42. Relative Humidity: 0~95% (No condensation)
  43. Altitude: ≤ 1000 m (Rated capacity), 1000-3000 m (De-rating 1% per 100 m)


Rear/Front Connection Type Products

 
  1. Rated Voltage: AC 400 V, AC 690 V
  3. Electrical Specification
  4. Input Voltage Range
    AC 400 V: AC 308~456 V, AC 308~480 V
    AC 690 V: AC 384~880 V
  5. Electric Connection
    AC 400 V: 3P4W, 3P3W
    AC 690 V: 3P3W
  6. Rated Frequency: 50(60) Hz ± 10%
  7. Input Voltage THD Range: ≤ 15%
  8. Rated Current per Module
    AC 400 V: 50 A, 75 A, 100 A
    AC 690 V: 100 A
  9. Rated Current per Cabinet
    AC 400 V: 50~700 A (Module combination)
    AC 690 V: 100~500 A (Module combination)
  10. Redundancy: Each module is an independent filtering system
  11. Harmonic Elimination Range
    AC 400 V: 2nd~50th order (Selectable)
    AC 690 V: 2nd~31st order (Selectable)
  12. Harmonic Filtering Degree
    0~100% programmable per harmonic in Ampere value
  13. Harmonic Filtering Performance: Filter up to 98% harmonics at rated load, THDv < 3%, THDi < 5% after filtering
  14. Reactive Power Compensation Capability: Both inductive and capacitive reactive power
  15. Reactive Power Compensation Performance: PF ≥ 0.99 after compensation (if the APF capacity is sufficient)
  16. Imbalance Correction Capability
    AC 400 V: Mitigate negative and zero sequence
    AC 690 V: Mitigate negative sequence
  17. Full Response Time: < 20 ms
  18. Instant Response Time: < 100 us
  19. Thermal Loss: ≤ 3% of APF rated capacity (kVA)
  20. Output Current Limitation: Automatic (100% rated capacity)
  21. Parallel Expansion (System): Up to 10 Racks (7 modules per cabinet)
  22. MTBF: > 100,000 hours
  24. Control Technology
  25. Switching Frequency
    AC 400 V : 60 kHz, 30 kHz
    AC 690 V: 30 kHz
  26. Controller: DSP control
  27. Communication: Modbus RTU (RS-485), Modbus TCP/IP (Ethernet)
  29. Physical Specification
  30. IP Grade of Cabinet: IP20, IP30, IP42, IP54 or customization
  31. Cooling Method: Intelligent forced air cooling
  32. Noise Level
    AC 400 V: < 65 dB(A) @1 m (Module)
    AC 690 V: < 70 dB(A) @1 m (Module)
  33. Dust Filter: Optional
  34. Dimension: Please download the brochure and refer to APF model table
  35. Weight: Please download the brochure and refer to APF model table
  37. Environmental Requirement
  38. Ambient Temperature
    Rear connection type: -10~50°C with 100% capacity, de-rating running from 50~55°C
    Front connection type: -25~40°C with 100% capacity, de-rating running from 40~55°C
  39. Relative Humidity: 0~95% (No condensation)
  40. Altitude: ≤ 1000 m (Rated capacity), 1000-2000 m (De-rating 1% per 100 m)

  42. All specifications are subject to change without prior notice.
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