Analysis of variable active-passive reactance

The characteristics of variable active-passive reactance (VAPAR) are analyzed. VAPAR, which consists of an inverter and passive elements, behaves like a two-port variable reactance element, and it works as a passive reactive component, including in the transient state. The disadvantage of VAPAR is in the requirement of DC voltage source. If a DC voltage source is replaced with a capacitor, a VAPAR can be considered as a complete two-port element. However, the DC voltage of the capacitor fluctuates in response to the stored energy in VAPAR. This situation causes changes in the inverter operation, such as switching frequency, harmonics and so on. The authors clarify the relationship between the stored energy and inverter operation, and present a method of capacitor selection.<>