General description:

The high-voltage VFD cabinet is for starting of high-voltage motor. The advanced power unit series superposition technology, vector control technology, and optimized PWM control algorithm are adopted to transform the 50Hz grid voltage into a 0~50Hz (60Hz) variable frequency and variable voltage sinusoidal voltage and sinusoidal current output, adjust the motor speed, and meet the user's urgent needs for speed regulation and energy saving of equipment such as fans and pumps and improvement of production processes.

2. Performance characteristics

◆High efficiency, high power factor, no harmonic pollution

TH-HVF series high-voltage variable frequency speed regulation system adopts the high-high solution of the power unit, and adopts a multi-winding high-voltage phase-shifting transformer. The current flowing through the secondary winding forms a sinusoidal current waveform when superimposed on the primary side of the transformer. The power factor is higher than 0.95, and the overall efficiency is higher than 98%. Multi-level technology is used to reduce the harmonic amplitude through superposition. The pure harmonic-free input does not interfere with the power grid. The output harmonic distortion is less than 2%, which meets and exceeds the provisions of the IEE519 international standard for power quality public power grid.

◆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 a bypass circuit is added to each power unit. When a power unit fails, the fault can be automatically monitored and the bypass circuit can be started, so that the unit is no longer put into operation, and then the angle between phases is adjusted through the line voltage automatic balancing technology to ensure the maximum line voltage balanced output under the premise that the phase voltage output is maximum and unequal.

◆Reliable oscillation suppression technology

When the motor is lightly loaded or unloaded, local instability will occur. At this time, the current amplitude fluctuates greatly, and the current oscillation may cause the system to trigger protection due to overcurrent or overvoltage. The superior current oscillation suppression algorithm can effectively suppress the current oscillation and ensure the stable and reliable operation of the system.

◆Flying car starting function

Flying car starting is also called speed tracking starting. It is mainly used in the process of starting and switching from industrial frequency to variable frequency when the fan rotates in the positive direction due to external force. With the flying start function, the inverter detects the actual speed of the rotor and then outputs the same frequency as the rotor, so that no electric energy will be fed back to the inverter DC bus, and there will be no overvoltage protection, so the motor can be started smoothly.

◆Disturbance-free switching between power frequency and inverter

It can realize disturbance-free switching between variable frequency and power frequency operation, and the switching process will not cause protection shutdown. The frequency conversion cuts to the power frequency by detecting the frequency, amplitude, and phase of the power frequency grid, adjusting the frequency, amplitude, and phase of the inverter output voltage to be consistent with the power frequency. After receiving the switching command, the inverter and the motor are disconnected, and then the motor is connected to the grid to realize the frequency conversion cut to power frequency process. Power frequency cuts to frequency conversion means that after the power frequency grid and the motor are disconnected, the inverter and the motor are connected, and then the inverter uses the flying start technology to drag the motor to run.

◆Multi-machine master-slave control technology

The inverter has the master-slave control function, and multiple inverters can form a master-slave control network through the data bus. One of them is set as the master and the others as slaves. The master collects the status information of each slave in real time and sends frequency and torque instructions to each slave to achieve power balance and comprehensive control of each inverter. This technology is suitable for occasions such as belt conveyors and hoists that require power balance control.