The high-voltage frequency conversion speed regulation system adopts the direct "high-high" conversion form, which is a multi-level topology structure of units in series. The main structure is composed of multiple groups of power modules in series and parallel. The transformer realizes direct 3kV, 6kV or 10kV high-voltage output; it has little harmonic pollution to the power grid, and the harmonic distortion of the input current is less than 4%, which directly meets the harmonic suppression standard of IEEE519-1992, and the input power factor is high. Harmonic filter and power factor compensation device; the output waveform quality is good, there is no additional heating of the motor caused by harmonics, torque ripple, noise, output dv/dt, common mode voltage and other problems, no need to add an output filter. Use a normal asynchronous motor.

     The so-called multiplexing technology is that each phase is composed of several low-voltage PWM power units in series, each power unit is powered by a multi-winding isolation transformer, controlled by a high-speed microprocessor and driven by optical fiber isolation. The multiplexing technology fundamentally solves the harmonic problem generated by the general 6-pulse and 12-pulse frequency converters. Each group consists of 8 power units with a rated voltage of 433V in series, so the phase voltage is 433V×8=3464V, and the corresponding line voltage is 6000V. Each power unit is powered by 24 secondary windings of the input isolation transformer, and the 24 secondary windings are divided into 8 groups, and there is a 7.5° phase difference between each group. The required phase difference angle can be achieved by different connection groups of the transformers. The high-voltage inverter composed of this multiplexing technology, also known as the unit series multi-level PWM voltage inverter, adopts the power unit series connection instead of the traditional device series connection to realize the high voltage output, so there is no device voltage equalization. problem.

     In metallurgical production, process parameters such as temperature, pressure and flow rate need to be adjusted according to different process requirements and operating conditions. In this way, no matter the size of the production demand, the fan and the water pump must run at full speed, and the change of the operating conditions causes the energy to be consumed by the throttling loss of the damper and baffle. In the production process, not only the control accuracy is limited, but also a lot of energy waste and equipment loss. As a result, the production cost is increased, the service life of the equipment is shortened, and the maintenance and repair costs of the equipment remain high.

     The energy-saving high-voltage inverter has been widely applied in the fields of dust removal fan, gas compressor, water supply and drainage of Maanshan Iron & Steel Co., Ltd., the energy saving effect is obvious, the electricity saving rate of the project is kept above 20%, and the investment recovery period is 2 to 3 years. , and achieved considerable economic benefits.

     Through the tracking and analysis of the actual performance of high-voltage frequency conversion energy-saving application, the high-voltage frequency conversion device operates stably and has a large space for energy saving; at the same time, the application of high-voltage frequency conversion device, while achieving higher energy-saving benefits, reduces the equipment caused by the direct start of fans and water pumps. Impact, reduce the amount of equipment maintenance, with high promotion and application value.