Dual two level inverter carrier SVPWM with zero common mode voltage

Conventional Space Vector PWM (CSVPWM) Voltage Source Inverters (VSI) are commonly used for adjustable speed drives. However, common mode voltage produced by these drives causes problems such as electromagnetic interference. A Space Vector PWM scheme for a dual converter has been presented in the past for eliminating common mode voltage while providing more maximum output voltage than a CSVPWM regulated VSI. In this paper, a carrier based implementation of that scheme has been presented. The algorithm does not require any square root or trigonometric calculations required by the Space Vector approach, but generates the duty ratios directly from the reference output phase voltages by simple logical operations. The paper also presents a method capable of producing switching sequence similar to CSVPWM for good output voltage quality. It requires sector determination, again from logical operations, but not the exact position of the reference output voltage space vector.