Patent ID: 8981705
Filing Date: 2015-03-17
Classification: H02K,H02P

Abstract:
1. A motor drive system comprising: a first capacitive element that stores energy to provide a first direct current (dc) voltage supply; a second capacitive element that stores energy to provide a second dc voltage supply; a first electrically conductive switch for electrically connecting in series with a winding of a single motor phase and the first capacitive element to form a first series circuit when the first switch conducts current; a second electrically conductive switch for electrically connecting in series with the motor phase winding and the second capacitive element to form a second series circuit when the second switch conducts current; a dc supply electrically connected in parallel with one of the first and second capacitive elements, such that substantially an entire voltage of the dc supply is applied across the one of the first and second capacitive elements; and a battery electrically connected in parallel with the one of the first and second capacitive elements that is not electrically connected in parallel with the dc supply, such that substantially an entire voltage of the battery is applied across the one of the first and second capacitive elements that is not electrically connected in parallel with the dc supply, wherein: the entire voltage of the first capacitive element is applied across the motor phase winding, less the voltage drop across the first switch and the voltage drop resulting from parasitic resistance in the first series circuit, when: (1) the second switch does not conduct current and (2) the second capacitive element is neither being charged nor discharged, and the entire voltage of the second capacitive element is applied across the motor phase winding, less the voltage drop across the second switch and the voltage drop resulting from parasitic resistance in the second series circuit, when: (1) the first switch does not conduct current and (2) the first capacitive element is neither being charged nor discharged.