Benefits of Energy Saving VSD Screw Compressor with Permanent Magnet Motor

Principle of Vector Control VSD Technology
The integrated flux vector control of the inverter system makes it possible to achieve high torques, even at low motor speeds. The sensor-less vector control system of the INV series enables fast, high-precision speed and torque regulation. Fast response/high accuracy speed control (zero speed control, servo lock), torque control and position control can be performed. Vector control frequency inverter offers excellent control characteristics when compared to traditional V/F control and other control techniques, achieving the control characteristics equal to those of DC machines. 
How does it actually be energy-saving?
First Saving: Air delivered according to system demands; on/off control losses are eliminated. VSD compressor precisely follows the varying air demand by adjusting motor rotation speed, this prevents unnecessary full load high current operation and energy consumed during unload operation (approx.45% of full load amount). 
Second Saving: Precise pressure control, avoiding wastage due to start/stop pressure band. VSD compressor delivers air at stable net pressure (e.g. 6bar.g), this not only maintains accurate target working pressure but also avoids losses due to high current operation within cut-in/cut-out pressure band. 
Standard compressor starts up under high current, it operates at full load condition until cut-out pressure (e.g. 8 bar.g) is reached, and starts up again when pressure drops to cut-in pressure (e.g. 6 bar.g). This start/stop control creates two wastages: (i) losses incurred during unload operation; (ii) losses due to 8-6=2 bar.g cut-in/cut-out differential pressure. 
Standard compressor operates between the range of 6 and 8 bar.g, it means 6 bar.g delivered pressure can meet with production requirement, the additional 2 bar.g pressure is an inherent wastage of standard compressor. 

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