Low cost high-side gate drive power supply for switched reluctance machines

The applications of switched reluctance machines in electrical vehicles, as well as in wind and hydro turbines, are gaining increasing attentions from the industries because of their low cost, low inertia and simple construction. In this paper, a low cost high-side power supply for the gate driver of switched reluctance machine is presented. With the use of a bootstrap technology, the high-side circuit acquires energy from the power supply of the low-side when the high-side switch is turned off. The acquired energy is utilized to support the high-side gate driver and current sensor when the phase winding is excited with the DC-link voltage. The circuit requires only a power diode and capacitor for each high-side power electronic switch. Comparing with traditional isolated power supply solutions, the cost and size of the proposed method are reduced. The necessary control algorithm of the gate drive to sustain the high-side voltage is also presented in this paper. Although it slightly increases the computational burden of the controller, it imposes no limit on the control of the phase winding of the machine with proper selection of the bootstrap capacitor. The guideline on the selection of the power electronic components is derived based on the parameters of the switched reluctance machine. Experimental results prove that the proposed scheme is practically feasible, for normal operations of SRM.