The of SNG5100 series high-voltage variable frequency speed regulating device is composed as follows:
6-10KV power is input to the phase-shifting isolation transformer through the high-voltage bypass cabinet, and the output supplies power for multiple IGBT power units of each phase through second windings that are multiply isolated of phase-shifting rectifier transformers. After multiple power units of each phase are cascaded, star connection is applied for unit output terminals, and high voltage is produced and output to high-voltage electric motors. This regulati ng device is a high-high voltage source high-pressure inverter with leading multiple level isolation technologies, and outputs pure sine waves with series overlaid multiple IGBT power units, thus guaranteeing high input power, low input current harmonics, and low input dv/dt. All these factors make the device a typical perfect harmony inverter. The master control unit of the system the core technologies of advanced transmission control technology, dedicated integrated double digital signal processor (DSP), and programmable logic controller (PLC). The unit is featured by very large scale integration (VLSI), accurate collected data, and high computing speed, and has perfect monitoring and protection functions. All control units communicate with the master control unit with optical fibers, which guarantees reliability control.

Each phrase of SNG5100 series 6KV high-voltage variable frequency speed regulation system is featured by cascading of 6 IGBT power units. Eighteen power units provide 36-impulse commutation tha t efficiently elimin ates 35 harmonics. Rated phase voltage of each unit is about 590 V, and each phrase has one IGBT power unit featured by automatic redundant standby replacement for each system, and rapid balance of output power of other power units.Each phrase of SNG5100 series 10KV high-voltage variable frequency speed regulation system is featured by cascading of 8 IGBT power units. Eighteen power units provide 48-impulse commutation that efficiently eliminates 47 harmonics. Rated phase voltage of each unit is about 750 V, and each phrase has one IGBT power unit featured by automatic redundant standby replacement for each system, and rapid balance of output power of other power units.For example, for 10KV regulation system, each power unit can accept all mot or currents, but only provides 1/8 phase voltage and 1/24 output power, as shown in Figure 2.