NC HVVF, integrating with the advanced power electronics technologies of the world, is a IGBT HVC independently developed by Nancal Energy-Saving Technology Co., Ltd.. PWM control technique is adopted to realize variable frequency control velocity of high-voltage motor. It is aimed to promote the performance of velocity variation startup of high-voltage motor, to improve control level, equipment power factor and operating efficiency of high voltage equipment, satisfy process control requirements, reduce energy consumption of the motor, as well as realize energy conservation and environmental protection. NC HVVF belongs to voltage source, high-high structural inverter. It adopts unit series and can realize voltage output of 0 ~ 6/10kV directly relying on the perfect sine wave generated based on the principle of phase shift superposition. No output voltage-boosting device is required. It can directly drive the normal motor. NC HVVF is as air-cooling model (10kV, 12500kVA). It water-cooling model (10kV, 25000kVA) has passed pattern test certification by a national authoritative organization.