High Voltage Variable Frequency Drive (VFD)

High Voltage Variable Frequency Drive (VFD)

The high voltage variable frequency speed regulation device produced by our company adopts advanced power unit series stacked wave technology, vector control technology, and optimized PWM control algorithm. It converts the 50Hz grid voltage into a sine voltage and sine current output of 0-50Hz (60Hz) variable frequency transformer, adjusts the motor speed, and meets the urgent needs of users for speed regulation, energy saving, and production process improvement of equipment such as fans and pumps.

1、 Basic principles

By adopting advanced power unit series stacked wave technology, vector control technology, and optimized PWM control algorithm, the 50Hz grid voltage is converted into sine voltage and sine current output of 0-50Hz (60Hz) variable frequency transformer, and the motor speed is adjusted to meet the urgent needs of users for speed regulation, energy saving, and production process improvement of equipment such as fans and pumps.

2、 Performance characteristics

1. High efficiency, high power factor, and no harmonic pollution: The high-voltage variable frequency speed regulation system adopts a high high scheme of power units, using a multi winding high-voltage phase-shifting transformer. The current flowing through the secondary winding forms a sinusoidal current waveform when stacked on the primary side of the transformer. The power factor is higher than 0.95, and the overall efficiency is higher than 98%. Adopting multi-level technology to reduce harmonic amplitude through superposition, the pure and harmonic free input does not cause any interference to the power grid, and the output harmonic distortion is less than 2%, meeting and exceeding the requirements of the IEE519 international standard for power quality public grids.
2. Advanced fault unit bypass operation technology: In order to improve the reliability of the system, a certain output voltage margin is considered in the entire variable frequency speed regulation system, and bypass circuits are added to each power unit. When a power unit fails, it can automatically monitor the fault and activate the bypass circuit, so that the unit is no longer in operation. Then, the line voltage automatic balancing technology is used to adjust the angle between the phase and the phase, ensuring the maximum line voltage balanced output under the premise of maximum and unequal phase voltage output.
3. Reliable oscillation suppression technology: Local instability may occur when the motor is lightly or unloaded, and the current amplitude fluctuates greatly. The oscillation of the current may cause the system to trigger protection due to overcurrent or overvoltage. Adopting superior current oscillation suppression algorithms can effectively suppress current oscillations and ensure stable and reliable operation of the system.
4. Flying car starting function: Flying car starting, also known as speed tracking starting, is mainly used in the process of starting and switching from power frequency to frequency conversion when the fan rotates in the positive direction due to external force. By using the high-speed starting function, the frequency converter detects the actual speed of the rotor and outputs the same frequency as the rotor, so that there is no electrical energy feedback to the DC bus of the frequency converter, and there is no overvoltage protection, thus smoothly starting the motor.
5. Non disturbance switching of industrial frequency conversion: It can achieve non disturbance switching between frequency conversion and power frequency operation, and the switching process will not cause protection shutdown. Frequency conversion to power frequency cutting is achieved by detecting the frequency, amplitude, and phase of the power grid, adjusting the frequency, amplitude, phase, and power frequency of the output voltage of the frequency converter to be consistent. After receiving the switching command, the frequency converter and motor are disconnected, and then the motor is connected to the power grid to achieve the frequency conversion to power frequency cutting process. Frequency conversion refers to the process of disconnecting the power grid from the motor, connecting the frequency converter to the motor, and then using high-speed starting technology to drive the motor.
6. Multi machine master-slave control technology: The frequency converter has master-slave control function, and multiple frequency converters can form a master-slave control network through a data bus. Set one of them as the host and the others as the slaves. The host will collect real-time status information from each slave and send frequency and torque commands to each slave, achieving power balance and comprehensive control of each inverter. This technology is suitable for occasions such as belt conveyors and elevators that require power balance control.