The Charging Strategy Selection for Variable-Frequency Electric Drive with Supercapacitors

A description of variable frequency electric drive with an energy storage device based on supercapacitor connected to the DC link of PWM inverter through a bidirectional DC/DC converter is given. The energy storage device has a single-loop control system of external current for a bidirectional DC/DC converter. The structure of the current controller and the function of the elements are illustrated. The simulation results, for various options for the initial charge of the DC link capacitor and a supercapacitor in energy storage device at various voltage levels, are given. The research aim is to identify the transient features in energy storage device and electric drive. The results can be useful in the control systems development for energy storage devices to improve the energy efficiency of variable frequency drives.