Three‐phase quasi‐Z source inverters with regulated multiple AC outputs for microgrid applications and three‐phase residential load

Abstract

In this study, two 3-φ quasi-Z source inverters (qZSIs) with multiple ac outputs are proposed. The proposed topologies are developed from qZSI to obtain parallel mode and series mode 3-φ multi-output inverters. In parallel mode, the topology yields n-number of parallel ac outputs with different voltages and currents for different load conditions. For series mode, topology yields n-number of series ac outputs with same voltages and same load currents. Unlike voltage source derived multi-output inverters, the proposed inverters have all inherent properties of qZSI, like shoot-through protection and both buckboost operations. For generating switching signals in these inverters, sinusoidal pulse width modulation with constant frequency shoot-through scheme is used. The proposed topologies fulfil more than one load demand at a time without any extra adaptor or regulator. The proposed inverters can be used for simultaneous multiple dc/ac power conversion for three-phase microgrid applications and three-phase residential loads. In this work, the proposed topologies with closed-loop control have been implemented for two inverter units, which is capable of supplying two ac outputs simultaneously. The mathematical modelling of the proposed topologies is carried out for performance analysis. The experimental results of 240 W lab prototypes have been presented to validate the proposed three-phase multi-output qZSIs.

A quantitative harmonics analysis approach for sinusoidal pulse‐width‐modulation based Z‐source inverters

“…Among the five types of control methods of a single-phase Z-source inverter, that is, one-cycle PWM control, modified reference PWM, hysteresis current control, non-linear sinusoidal PWM and low-frequency harmonics elimination PWM, shoot-through by overlapping of active states would lead to minimum switching loss and higher efficiency [9,26]. The effects of ST states on voltage waveforms V AO , V BO and V Z are illustrated in Figure 2.…”

“…A circulating current model was built [21] to analyse the influence of dead time with different PWM schemes for three-phase inverters. Moreover, a series of harmonics compensation or suppression control approaches for conventional inverters [22][23][24][25][26][27] were proposed for the motor drive or microgrid applications. Though the proposed quantitative analysis of ST states and output harmonics is inspired by the above literature for conventional PWM inverters, the intrinsic differences between traditional inverters and Z-source inverters have made the analysis complicated and challenging.…”

Review of impedance source power converter for electrical applications

“…The mathematical modelling of the proposed topologies is carried out for performance analysis. The experimental results of 240 W lab prototypes have been presented to validate the proposed three-phase multi-output qZSIs [75].…”

A Quasi-Z-Source Four-Switch Three-Phase Inverter With Null Vector Capability

“…The main feature of the ZSIs is their impedance networks with shoot-through capability that is used to buck or boost the voltage. During the shoot-through state, the upper and lower switches of the ZSIs are simultaneously turned on, while this state is not allowed in the traditional voltagesource inverters (VSI) [15], [16]. However, the conventional ZSI with X-shaped impedance source, proposed by Peng [17], has some drawbacks such as: inrush current during the start-up and also high voltages and currents stresses on the components [18]- [23].…”