A variable voltage converter for an electric drive system has upper and lower switching devices in series between positive and negative buses. An inductance couples a junction between the switching devices to a DC battery. A controller is configured to drive the switches according to PWM gate signals based on an expected boost ratio of the converter. The PWM gate signals have a nominal dead-time insertion for both the upper and lower switching devices when the expected boost ratio is greater than a predetermined boost ratio. In order to extend a range of achievable boost ratios during regeneration operation, the PWM gate signals are without dead-time insertion for the upper switching device and the lower switching device remains continuously off when the expected boost ratio is less than the predetermined boost ratio.