A chiller system is provided with a compressor, a condenser, and an evaporator connected in a closed refrigerant loop. A motor is connected to the compressor to power the compressor. A variable speed drive is connected to the motor. The variable speed drive is arranged to receive an input AC power at a fixed input AC voltage and a fixed input frequency and provide an output power at a variable voltage and variable frequency to the motor. The variable voltage has a maximum voltage greater in magnitude than the fixed input AC voltage and the variable frequency has a maximum frequency greater than the fixed input frequency. The variable speed drive includes a converter connected to an AC power source providing the input AC voltage, the converter is arranged to convert the input AC voltage to a DC voltage. A DC link is connected to the converter. The DC link is arranged to filter and store the DC voltage from the converter. An inverter is connected to the DC link. A controller is arranged to reference a first operating map associated with the compressor, a second operating map associated with the motor, and a third operating map associated with the variable speed drive. The controller further is arranged to analyze the first operating map second operating map and third operating map concurrently to select an operating point for the chiller system.