A charging system using a line voltage for charging an energy storage system, ESS using a polyphase motor drive circuit communicated to a polyphase motor, the polyphase motor drive circuit including a plurality M of driver stages, one driver stage for each phase of the polyphase motor with each driver stage coupled across the energy storage system, the system comprising: a converter, coupled to the energy storage system and to the plurality of driver stages, having a first mode and a second mode, the first mode characterized in said converter converting the line voltage to a first charging voltage, the conversion using a first set of N number of the plurality of driver stages, when in said first mode, with N less than M, wherein said first charging voltage is communicated to the energy storage system and wherein said first charging voltage is greater than the line voltage, and the second mode characterized in said converter converting the line voltage to a second charging voltage, the conversion using a second set of P number of the plurality of driver stages, when in said second mode, with P greater than N, wherein said second charging voltage is communicated to the energy storage system and wherein said second charging voltage is less than the line voltage; a mode control, responsive to a voltage comparison between the line voltage and an ESS voltage of the energy storage system, for changing said converter from said boost mode to said boost-buck mode when the line voltage has a first predetermined relationship to said ESS voltage and for changing said converter from said second mode to said first mode when said ESS voltage exceeds the line voltage by at least a specific margin; and a controller, coupled to said converter and to said mode control, for operating said converter and said mode control to charge the energy storage system in said first mode and in said second mode. a converter, coupled to the energy storage system and to the plurality of driver stages, having a first mode and a second mode, the first mode characterized in said converter converting the line voltage to a first charging voltage, the conversion using a first set of N number of the plurality of driver stages, when in said first mode, with N less than M, wherein said first charging voltage is communicated to the energy storage system and wherein said first charging voltage is greater than the line voltage, and the second mode characterized in said converter converting the line voltage to a second charging voltage, the conversion using a second set of P number of the plurality of driver stages, when in said second mode, with P greater than N, wherein said second charging voltage is communicated to the energy storage system and wherein said second charging voltage is less than the line voltage; a mode control, responsive to a voltage comparison between the line voltage and an ESS voltage of the energy storage system, for changing said converter from said boost mode to said boost-buck mode when the line voltage has a first predetermined relationship to said ESS voltage and for changing said converter from said second mode to said first mode when said ESS voltage exceeds the line voltage by at least a specific margin; and a controller, coupled to said converter and to said mode control, for operating said converter and said mode control to charge the energy storage system in said first mode and in said second mode.