Resonance Investigation for Single-Stage Current Source Inverters in Electric Drives Applications

Single-stage Current Source Inverters (CSIs), supplied by a DC voltage source, are an alternative to Voltage Source Inverters (VSIs) for applications that operate always above a base speed due to their intrinsic boost capability that allows to achieve higher speeds with limited DC voltage. The resonance problem given by the interaction between the output capacitor Cf and the motor inductor L0 has been extensively studied for CSIs. Furthermore, it is found that the inductor Ldc on the DC side also affects the resonance. This leads to an additional LCL resonance on the output currents. This paper investigates the resonances of single-stage CSI using the average small-signal converter model. An analytical expression for the additional LCL resonance is computed and a control strategy is proposed to attenuate the peaks of the resonances. Simulations are reported to evaluate the correspondence between the average small-signal model and the full model developed in PLECS.