Effects of different chopping modes on the thrust ripple of electromagnetic launchers

Brushless DC linear motors have considerable advantages of simpler structure, higher efficiency, higher thrust density and so on. They are well suited for many domains such as electromagnetic launch and launch-assist, and their winding currents usually are square-wave. Firstly, this paper analyzes the effects of commutation, bus voltage and motor parameters on the thrust ripple of electromagnetic launchers without chopping control by using analytic methods, and related experimental research has been carried out after a small scale laboratory model being made. Then types and features of chopping modes are briefly introduced and the effects of different chopping modes on the thrust ripple of electromagnetic launchers are analyzed by using analytic methods. Lastly a small scale laboratory model is made according to the motor parameters adopted from the analytical mathematical model and related experimental researches have been carried out. Satisfactory results are reached and agree with the theoretical analysis.