High efficiency flexible converter

A method of conditioning AC input power received from an input with one or more of a rectifier including one or more rectification switches, an inverter having one or more main branch switches and one or more freewheeling switches, and an auxiliary branch having one or more auxiliary switches, to provide AC output power to an output having an output inductor, the method comprising:

• receiving input voltage information indicative of a voltage level of the AC input power;
• receiving output voltage information indicative of a voltage level of the AC output power;
• selecting, based on a determination that the input voltage information and the output voltage information satisfy a first condition at a first time, a buck mode of operation;
• selecting, based on a determination that the input voltage information and the output voltage information satisfy a second condition at a second time, a freewheel mode of operation, wherein satisfying the second condition includes determining that the voltage level of the AC input power is less than the voltage level of the AC output power;
• operating the one or more main branch switches to generate the AC output power and provide the AC output power to the output responsive to the second condition being satisfied;
• and
• operating the one or more auxiliary switches to freewheel during flyback of the output inductor responsive to the second condition being satisfied.

An Uninterruptible Power Supply (UPS) system, the system comprising:

• an input configured to receive AC input power;
• an output configured to provide AC output power to at least one load;
• a rectifier coupled to the input, the rectifier having one or more rectification switches;
• an inverter coupled to the rectifier at a first connection and coupled to the output at a second connection, the inverter having one or more main branch switches and one or more freewheeling switches;
• an auxiliary branch coupled to the input at a first connection and coupled to the output at a second connection, the auxiliary branch having one or more auxiliary switches;
• and
• a controller coupled to the rectifier, the inverter, and the auxiliary branch, and configured to:
• receive input voltage information indicative of a voltage level of the AC input power;
• receive output voltage information indicative of a voltage level of the AC output power;
• select, based on the input voltage information and the output voltage information satisfying a first condition, a buck mode of operation;
• select, based on the input voltage information and the output voltage information satisfying a second condition, a freewheel mode of operation;
• select a stop mode of operation responsive to determining that a polarity of the voltage level of the AC input power is opposite a polarity of the voltage level of the AC output power;
• and
• communicate one or more control signals to at least one of the rectifier, the inverter, and the auxiliary branch based on the selected mode of operation.