Open Loop Variable Frequency Medium High Voltage AC Drives 3 Phase

ZF-BP Series V/F Control High Voltage Variable Frequency Drive

V/F control high-voltage inverter is a high-voltage power conversion equipment based on voltage frequency ratio (V/f) control technology, designed specifically for high-voltage motors. By adjusting the proportional relationship between output voltage and frequency, it achieves stable control of motor speed and torque. The V/F control high-voltage frequency converter takes constant voltage frequency ratio as the core, and achieves motor speed regulation through open-loop control. It has the advantages of low cost, strong stability, and wide speed regulation range, and is widely used in constant torque load scenarios such as fans and pumps

Working Principle

• Constant voltage frequency ratio control: The core of V/f control is to maintain a constant ratio of voltage to frequency (V/f=constant), thereby ensuring a constant magnetic flux in the motor.
• Magnetic flux stability: During the speed regulation process, the output voltage and frequency are adjusted to ensure that the magnetic flux of the motor remains constant at different speeds, avoiding weak or magnetic saturation phenomena.
• Open loop control: No speed feedback required, direct control of motor operation through preset V/f curve

Characteristic

• Simple structure: The control circuit design is concise and cost-effective.
  Wide speed regulation range: suitable for speed regulation requirements from 0 to rated speed, but torque performance decreases at low speeds.
• Low speed torque compensation: By increasing the low-frequency voltage to compensate for the stator resistance drop, the low-speed starting performance is improved.
• High cost-effectiveness: No need for high-precision sensors and complex algorithms, suitable for cost sensitive applications.
• Applicable load types: mainly used for square torque loads such as fans and pumps, as well as situations where the load torque changes little with speed.

Application

• Fan and water pump: flow and pressure regulation are achieved through V/f control to meet the needs of constant pressure water supply, ventilation systems, etc.
• Conveying equipment: such as belt conveyors, elevators, etc., which require smooth speed regulation and do not require high dynamic performance requirements.
• Energy saving renovation: In old high-voltage motor systems, energy saving and consumption reduction are achieved through V/f control of frequency converters.
• Industrial general equipment: suitable for machinery with low requirements for speed regulation accuracy and small load torque fluctuations.