Loss minimization of electric drive systems using a DC/DC converter and an optimized battery voltage in automotive applications

Voltage source inverters generally feed the traction motor from a battery in automotive applications. By implementing a DC/DC converter between battery and inverter, the DC-link voltage is adjustable. This paper discusses the benefits of the variable DC-link voltage as an additional degree of freedom for a loss minimized control of electric drives in battery supplied vehicles. Inverter systems with and without DC/DC converter are compared and operating areas of improved efficiency are identified. Energy saving potentials resulting from an optimized battery voltage are discussed for different driving cycles.