| Standard low and medium power drives are based on the voltage-source converter topology. There has been less research work into dual topology drives, based on a current-fed inverter structure. Although energy storage is more efficient in capacitors than in inductors, due to some inherent advantages of current-source converter topology (such as short-circuit protection and high reliability due to use of unidirectional switches), and at the first place, the absence of DC link electrolytic capacitor; a current-source drive system made with a considerably reduced DC link inductor could be better low-cost solution with improved reliability, lifetime and transient response than conventional drive.; This research work is about new current-fed drive topology with sinusoidal input currents, which is applied to a permanent magnet synchronous machine in low-cost applications. A three-switch front end PWM buck rectifier with an appropriate control technique, a simple thyristor inverter at the output, together with small DC choke (which can be embedded into machine), offers virtually an inductorless integrated drive system solution and could challenge standard industry solutions. A laboratory prototype has been fabricated using discrete switching devices and standard analog and digital circuits. System description, analysis, design guidelines, simulated results and measured experimental results are presented. |
