Space Vector Pulsewidth Amplitude Modulation for a Buck–Boost Voltage/Current Source Inverter

This paper proposes a space vector pulsewidth amplitude modulation (SVPWAM) method for a buck-boost voltage/current source inverter. For a voltage source inverter, the switching loss is reduced by 87%, compared to a conventional sinusoidal pulsewidth modulation (SPWM) method. For a current source inverter, the switching loss is reduced by 60%. In both cases, the power density is increased by a factor of 2 to 3. In addition, it is also verified that the output harmonic distortions of SVPWAM is lower than SPWM, by only using one-third switching frequency of the latter one. A 1-kW boost-converter-inverter prototype has been built and tested using this modulation method. The maximum overall system efficiency of 96.7% has been attained at full power rating. The whole system power density reaches 2.3 kW/L and 0.5 kW/lb. The numbers are remarkable at this power rating. As a result, it is feasible to use SVPWAM to make the buck-boost inverter suitable for applications that require high efficiency, high power density, high temperature, and low cost. Such applications include electric vehicle motor drive or engine starter/alternator.