1. Voltage balancing control of diode-clamped multilevel converters with passive front-ends
- Author
-
Busquets-Monge, Sergio, Alepuz, Salvador, Bordonau, Josep, and Peracaula, Juan
- Subjects
Electric current converters -- Design and construction ,Capacitors -- Design and construction ,Voltage -- Control ,Pulse-duration modulation -- Methods ,Clamping circuits -- Design and construction ,Electric current converter ,Business ,Electronics ,Electronics and electrical industries - Abstract
In the previous literature, it has been reported that it is not possible to guarantee the balance of the dc-link capacitor voltages of multilevel three-phase diode-clamped dc-ac converters with passive front-ends for high modulation indices, especially for more than three levels. This paper proposes a novel closed-loop control approach capable of guaranteeing such balance for all operating conditions of the converters without the need for additional hardware. Three different phase duty-ratio perturbation schemes are proposed. They are compared through simulation for the case of a four-level three-phase diode-clamped dc-ac converter operated with a virtual-vector-based modulation. The most simple and effective perturbation scheme, only requiring the sensing of all dc-link capacitor voltages, is tested experimentally in the same four-level converter. The results demonstrate the feasibility of guaranteeing the dc-link capacitor voltage balance for all converter operating conditions. Index Terms--Capacitor voltage balance, diode-clamped, multilevel, pulsewidth modulation (PWM), virtual vector.
- Published
- 2008