ZFeng 900 Series 560Kw-T-G General Vector Variable Frequency Drive

The high-power frequency converter developed and produced by our company precisely controls the speed of three-phase AC motors by changing the frequency and voltage of the power supply. Its core lies in the three major links of rectification inverter control.

• Rectification: Convert alternating current into direct current
  Input stage: The frequency converter receives three-phase AC power (such as 380V/50Hz) and converts it into pulsating DC power through a rectifier bridge (composed of high-power diodes or thyristors).
  Filtering stage: After being filtered by capacitors, pulsating DC power becomes a stable DC bus voltage (approximately 540V, based on 380V input).
  Analogy: Comparing alternating current to "waves", rectifiers "flatten" the waves into "flat current" (direct current).
• Inverter: Convert direct current into adjustable frequency alternating current
  Core components: Using IGBT (Insulated Gate Bipolar Transistor) or SiC (Silicon Carbide) power modules, direct current is chopped into PWM (Pulse Width Modulation) signals through high-frequency switches (usually several thousand to tens of kilohertz).
  Frequency control: By adjusting the switching frequency and duty cycle of IGBT, generate AC power with variable frequency and voltage. For example:
  Frequency increase → Motor speed increases
  Voltage reduction → adapt to light load conditions
  Analogy: Inverters are like "music synthesizers" that "modulate" direct current into alternating current of different tones (frequencies) and volumes (voltages) through quick switching.
• System: Achieving high-precision speed regulation and protection
  Control algorithm: Vector Control (FOC): Decompose the motor current into torque and excitation components to achieve independent control, suitable for high dynamic performance requirements.
  Direct Torque Control (DTC): Directly controls torque and magnetic flux, with faster response speed but slightly larger torque fluctuations.
  Protection function: Built in overload, overvoltage, undervoltage, overcurrent, overheating and other protection mechanisms ensure equipment safety.
  Analogy: The control algorithm is like an "intelligent driving system", dynamically adjusting the motor output according to the load demand to ensure smooth operation.

Key technical points

• PWM modulation technology: Generate an approximate sine wave voltage through high-frequency switches to reduce harmonic interference.
• Energy feedback: During braking or deceleration, the energy feedback from the motor is fed back to the grid through an inverter to improve energy efficiency.
• Heat dissipation design: High power frequency converters need to be equipped with water cooling or forced air cooling systems to ensure stable operation of IGBT and other devices at high temperatures.

GuangDong Zhufeng Electric Co.,LTD established in 2004, is a national high-tech and energy save enterprise with approval by National Development and Reform Commission. Focusing on the development and production and sale of products of “energy saving and control speed and variable speed” , Zhufeng has been a very good supplier for energy saving and automation control solutions . With it’s own brands: “ACI”,“ZFENG”, Zhufeng has developed DLT series products including vector and universal variable frequency drive, servo system, energy saving cabinet, industrial power saver, soft starter etc. Applications including ceramic, machinery, petrochemical, metal, textile, food, papermaking, cement, water supply, plastic injection, central air-conditioning, smart building,etc.