Abstract
This thesis develops a switched-reluctance motor (SRM) driven flywheel and performs its application of energy support to motor drive. After exploring the basics and key control issues of a SRM in motoring and generating modes, the power circuit and control schemes of the established SRM flywheel are designed and implemented. In flywheel charging mode, through the designed commutation, PWM current control and speed control schemes, the motor driven flywheel possesses smooth acceleration characteristics. Conversely in flywheel discharging mode, in addition to the proper commutation instant setting, the hysteresis current control with hard freewheeling is adopted to counteract the effects of positive back electromotive force (EMF). The studied SRM drive is powered from the mains via a single-phase H-bridge switch-mode rectifier (SMR) followed by an one-leg bidirectional buck/boost converter. The bidirectional power flow capability with good line drawn power quality control capability is possessed. In driving mode, the boosted and well-regulated SRM drive DC link voltage is established to enhance the motor driving performance under higher speeds. And the regenerative braking energy can be recovered back to the DC link. The DC link of SRM drive can be supported energies from a hybrid energy storage system (HESS), which consists of the developed flywheel and an energy harvesting scheme with possible DC inputs such as battery, supercapacitor (SC), fuel-cell, photovoltaic, etc. While the energy harvesting scheme utilizes the buck-boost/buck-boost bidirectional DC/DC converter as the interface, the SRM driven flywheel adopts the one-leg buck/boost bidirectional DC/DC converter. The possible operations of the established motor drive include: (i) The operation of SMR-fed SRM drive; (ii) As the grid power outage occurs, the motor drive can be supported energy from the HESS. Conversely, the storage devices in the HESS can be charged from the mains; (iii) The intermittent load energy requirement can be quickly supplied by the flywheel. Some measured results are provided to demonstrate the operating characteristics of all power stages in various conditions.