BIDIRECTIONAL POLYPHASE MULTIMODE CONVERTER INCLUDING BOOST AND BUCK-BOOST MODES

A charging method using a multiphase 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 method including the steps of: (a) determining a charge mode responsive to a comparison of the multiphase line voltage to a voltage of the energy storage system, the determined charge mode including a boost mode when the voltage of the energy storage system has a first predetermined relationship to the multiphase line voltage and the determined charge mode including a boost-buck mode when the voltage of the energy storage system has a second predetermined relationship to the multiphase line voltage; (b) converting, when the charge mode includes the boost mode, the multiphase line voltage to a first charging voltage using a first set of N number of the plurality of driver stages, with N less than M, wherein the first charging voltage is communicated to the energy storage system, and wherein the first charging voltage is greater than the multiphase line voltage; and (c) converting, when the charge mode includes the boost-buck mode, the multiphase line voltage to a second charging voltage using a second set of P number of the plurality of driver stages when in the boost-buck mode, with P greater than N, wherein the second charging voltage is communicated to the energy storage system, and wherein the second charging voltage is less than the multiphase line voltage.