Five-Phase Inverters with Synchronized PWM

Abstract

Novel method of synchronized pulsewidth modulation (PWM) has been developed for control of a fivephase inverter. It allows synchronization of the phase-toneutral voltages in five-phase systems during the whole control range, including the zone of overmodulation. Control algorithm is based on 22 voltage vectors in the linear modulation region and on 12 space-vectors during overmodulation. Space-vector approach for determination of the pulse patterns provides minimum number of switchings and minimal switching losses in the system. Simulations give the behavior of the five-phase inverters with synchronized PWM. The spectra of the phase-toneutral voltage of five-phase power conversion systems with algorithms of synchronized PWM do not contain even harmonics and sub-harmonics during the whole control range, which is especially important for the high power/current applications.

Methods of voltage synchronization in multiphase power conversion systems

“…16 shows the basic ten large (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) and ten medium (1', 2', 3', 4', 5', 6', 7', 8', 9', 10') switching vectors for a five-phase inverter in accordance with conventional designation (in brackets) of switching state of every switch of the inverter, where "1" corresponds to the switch-on state of the corresponding switch of the upper group of switches of the phases a -e. This control scheme includes also two zero switching states (00000 and 11111), providing zero voltage at the outputs of the inverter. Although total number of available voltage space vectors in five-phase inverter is equal to 32, the using only of the mentioned above 20 vectors (ten large and ten medium active vectors) plus two zero switching sequences allows minimum number of switchings and minimal switching losses, combined with good spectrum of the phase-to-neutral voltage in the linear modulation range [14], [15]. Overmodulation control of five-phase systems can be based on the use of ten large vectors and two zero switching sequences [15].…”

“…Although total number of available voltage space vectors in five-phase inverter is equal to 32, the using only of the mentioned above 20 vectors (ten large and ten medium active vectors) plus two zero switching sequences allows minimum number of switchings and minimal switching losses, combined with good spectrum of the phase-to-neutral voltage in the linear modulation range [14], [15]. Overmodulation control of five-phase systems can be based on the use of ten large vectors and two zero switching sequences [15].…”

“…19, modulation index m=0.62 in the case of scalar control mode), and to 39 Hz (Fig. 20, m=0.78) [15]. The switching frequency is 2.3 kHz.…”

Simplifying approach for analysis of space-vector PWM for three-phase and multiphase converters

“…Although total number of available voltage space vectors in five-phase inverter is equal to 32, the using only of the mentioned above 20 vectors (ten large and ten medium active vectors) plus two zero switching sequences allows minimum number of switchings and minimal switching losses, combined with good spectrum of the phase-to-neutral voltage in the linear modulation range [16], [17]. During overmodulation control of five-phase systems is based on the using of only ten large vectors and two zero switching sequences [17].…”

“…Ones of the interesting structures of multiphase systems are five-phase power conversion systems based on five-phase inverters [15]- [17]. Basic topology of power circuit of a five-phase voltage source inverter with a star-connected load with the neutral point n is presented in Fig.…”