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The comparison between static frequency converter and frequency inverter

2026-01-31

Design purpose ‌	To provide a high-quality, pure and reliable AC test power supply for precision electronic devices.	Designed specifically for controlling AC motor speed for energy savings and process control.
output waveform ‌	Output pure sine waves with low waveform distortion (<2%).	Output PWM-modulated waves with high-order harmonics that may interfere with sensitive equipment.
application ‌	Electronic and electrical product research and development testing, export product certification, laboratory precision measurement, vessel load etc.	Energy-saving control of fans and pumps, speed regulation of conveyor belts on production lines, industrial automation, etc.
control accuracy ‌	Voltage stability ±0.5%, frequency stability ±0.1%, fast response speed.	Voltage control accuracy ±5%, frequency control accuracy ±0.5%, with emphasis on torque and speed regulation performance.
protection features ‌	Overvoltage, overcurrent, overload and short circuit protection (automatic recovery).	Overcurrent, overvoltage, overload protection, with emphasis on motor protection.
Load adaptability ‌	It can drive various types of loads to ensure test accuracy and repeatability.	For three-phase asynchronous motors only, other loads may not work or damage the equipment.
Reliability	The overall design of the power supply, with years of technological accumulation, ensures stable and reliable operation of the power supply	The production of frequency inverter assembled through a variable frequency drive is relatively simple. Since its main component, the variable frequency drive, is purchased, it is difficult to ensure that the parameters of the variable frequency drive match those of other components.
For the safety of the equipment	Constant frequency during startup. A variable frequency power supply can provide a pure, reliable, low harmonic distortion, highly stable sinusoidal power output of voltage and frequency, very close to an ideal AC power supply.	The inverter is designed specifically for the variable frequency start-up of motors, where voltage and frequency rise simultaneously during start-up. The power supply modified with it may have an impact on electrical equipment, especially transformers, controlled rectifiers, communication equipment, etc
Three-phase imbalance	The inverter section operates in a star configuration, with each phase capable of carrying loads independently, accommodating three-phase completely unbalanced loads. The unbalance can be up to 3%.	The inverter uses Δ inversion, and although the output is transformed into Y-type output through a transformer, it has poor adaptability to three-phase unbalanced loads, which may increase the reverse torque in the motor, raise the motor temperature, reduce efficiency, increase energy consumption, cause vibration, and result in output loss